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Objective: To examine postpartum haemorrhage (PPH) trends in Sweden using the Robson classification system. Design: Population‐based cohort study. Setting: Sweden. Population: Deliveries in 2000–2016, classified as Robson groups 1–5 (singleton pregnancies in vertex presentation, from gestational weeks 37+0; n = 1 590 178). Methods: We examined temporal trends in PPH between 2000 and 2016 overall, and within each Robson group, and performed logistic regression to examine the influence of changes in risk factors (maternal, comorbidity, obstetric practice and infant factors) over time. Main outcome measures: Postpartum haemorrhage, defined as an estimated blood loss of >1000 ml. Results: The overall PPH rate increased from 5.4 to 7.3%, corresponding to a 37% (OR 1.37, 95% CI 1.32–1.42) increase over time. Rates varied between Robson groups, ranging from 4.5% in group 3 to 14.3% in group 4b. Increasing trends in PPH were found in all Robson groups except for groups 2b and 4b (prelabour caesarean deliveries). In the unstratified analysis, adjusting for maternal, comorbidity and obstetric practice factors slightly attenuated the risk of PPH in the later period (2013–2016), compared with the reference period (2000–2004; crude OR 1.26, 95% CI 1.24–1.29, adjusted OR 1.22, 95% CI 1.20–1.25). Within individual Robson groups, changes in risk factors did not explain increasing rates of PPH. Conclusions: Postpartum haemorrhage rates varied between Robson groups. Changes in risk factors could not explain the 37% increase in PPH for women in Robson groups 1–5 in Sweden, 2000–2016. Changes in risk factors could not explain the increasing trend of PPH in Sweden, and rates of PPH varied widely between Robson groups. Changes in risk factors could not explain the increasing trend of PPH in Sweden, and rates of PPH varied widely between Robson groups. [ABSTRACT FROM AUTHOR]

Objective: Second-stage cesarean delivery (CD) is associated with subsequent preterm birth (PTB). It has been suggested that an increased risk of PTB after second-stage cesarean delivery could be linked to a higher chance of cervical injury due to the extension of the uterine incision. Previous studies have shown that reverse breech extraction is associated with lower rates of uterine incision extensions compared to the "push" method. We aimed to investigate the association between the method of fetal extraction during second-stage CD and the rate of spontaneous PTB (sPTB), as well as other maternal and neonatal outcomes during the subsequent pregnancy., Methods: This was a multicenter retrospective cohort study. The study population included women in their first subsequent singleton delivery following a second-stage CD between 2004 and 2021. The main exposure of interest was the method of fetal extraction in the index CD ("push" method vs. reverse breech extraction). The primary outcome of this study was sPTB <37 weeks in the subsequent pregnancy. Secondary outcomes were overall PTB, trial of labor, and other adverse maternal and neonatal outcomes. Univariate analysis was followed by multiple logistic regression modeling., Results: During the study period, 2969 index CD during second stage were performed, of those 583 met the inclusion criteria, of whom 234 (40.1%) had fetal extraction using the reverse breech extraction method, while 349 (59.9%) had the "push" method for extraction. In univariate analysis, women in those two groups had statistically similar rates of sPTB (3.7% vs. 3.0%; odds ratio [OR] 1.25, 95% CI: 0.49-3.19) and overall PTB (<37, <34 and <32 weeks), as well as other maternal, neonatal, and trial of labor outcomes. This was confirmed by multivariate analyses with an adjusted OR of 1.27 (95% CI: 0.43-3.71) for sPTB., Conclusion: Among women with a previous second-stage CD, no significant difference was observed in PTB rates in the subsequent pregnancies following the "push" method compared to the reverse breech extraction method., (© 2024 The Authors. International Journal of Gynecology & Obstetrics published by John Wiley & Sons Ltd on behalf of International Federation of Gynecology and Obstetrics.)

Background: Infant health among newborns with neonatal abstinence syndrome (NAS) has been understudied. We examined infant mortality and hospitalizations among infants diagnosed with NAS after birth., Methods: All live births in British Columbia (BC), Canada, for fiscal years from 2004-2005 to 2019-2020, were included ( N  = 696,900). NAS was identified based on International Classification of Diseases, version 10, Canadian modification (ICD-10-CA) codes; the outcomes included infant death and hospitalizations during the first year of life, ascertained from BC linked administrative data. Generalized estimating equation models were used to adjust for maternal factors., Results: There were 2,439 infants with NAS (3.50 per 1,000 live births). Unadjusted for other factors, infant mortality was 2.5-fold higher in infants with vs. without NAS (7.79 vs. 3.08 per 1,000 live births, respectively) due to increased post-discharge mortality NAS (5.76 vs. 1.34 per 1,000 surviving infants, respectively). These differences diminished after adjustment: adjusted odds ratio (AOR) for infant death was 0.85 [95% confidence interval (CI): 0.52-1.39]; AOR for post-discharge death was 1.75 (95% CI 1.00-3.06). Overall, 22.3% infants with NAS had at least one hospitalization after post-neonatal discharge, this proportion was 10.7% in those without NAS. During the study period, discharge to foster care declined from 49.5% to 20.3% in infants with NAS., Conclusion: Unadjusted for other factors, infants with NAS had increased post-discharge infant mortality and hospitalizations during the first year of life. This association diminished after adjustment for adverse maternal and socio-medical conditions. Infants with NAS had a disproportionately higher rate of placement in foster care after birth, although this proportion declined dramatically between 2004/2005 and 2019/2020. These results highlight the importance of implementing integrated care services to support infants born with NAS and their mothers during the first year of life and beyond, even though NAS itself is not independently associated with increased infant mortality., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2024 Lisonkova, Wen, Richter, Ting, Lyons, Mitchell-Foster, Oviedo-Joekes, Muraca, Bayrampour, Cattoni and Abrahams.)

Objectives: Rates of severe maternal morbidity have highlighted persistent and growing racial disparities in the United States (US). We aimed to contrast temporal trends in peripartum hysterectomy by race/ethnicity and quantify the contribution of changes in maternal and obstetric factors to temporal variations in hysterectomy rates., Methods: We conducted a population-based, retrospective study of 5,739,569 US residents with a previous cesarean delivery, using National Vital Statistics System's Natality Files (2011-2021). Individuals were stratified by self-identified race/ethnicity and classified into four periods based on year of delivery. Temporal changes in hysterectomy rates were estimated using odds ratios (ORs) and 95% confidence intervals (CIs). We used sequential logistic regression models to quantify the contribution of maternal and obstetric factors to temporal variations in hysterectomy rates., Results: Over the study period, the peripartum hysterectomy rate increased from 1.23 (2011-2013) to 1.44 (2019-2021) per 1,000 deliveries (OR 2019-2021 vs. 2011-2013 = 1.17, 95% CI 1.10 to 1.25). Hysterectomy rates varied by race/ethnicity with the highest rates among Native Hawaiian and Other Pacific Islander (NHOPI; 2.73 per 1,000 deliveries) and American Indian or Alaskan Native (AIAN; 2.67 per 1,000 deliveries) populations in 2019-2021. Unadjusted models showed a temporal increase in hysterectomy rates among AIAN (2011-2013 rate = 1.43 per 1,000 deliveries; OR 2019-2021 vs. 2011-2013 = 1.87, 95% CI 1.02 to 3.45) and White (2011-2013 rate = 1.13 per 1,000 deliveries; OR 2019-2021 vs. 2011-2013 = 1.21, 95% CI 1.11 to 1.33) populations. Adjustment ranged from having no effect among NHOPI individuals to explaining 14.0% of the observed 21.0% increase in hysterectomy rates among White individuals., Conclusion: Nationally, racial disparities in peripartum hysterectomy are evident. Between 2011-2021, the rate of hysterectomy increased; however, this increase was confined to AIAN and White individuals., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Rajasingham et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: To quantify temporal trends and regional variation in severe maternal morbidity (SMM) in Sweden., Design: Cohort study., Population: Live birth and stillbirth deliveries in Sweden, 1999-2019., Methods: Types and subtypes of SMM were identified, based on a standard list (modified for Swedish clinical setting after considering the frequency and validity of each indicator) using diagnoses and procedure codes, among all deliveries at ≥22 weeks of gestation (including complications within 42 days of delivery). Contrasts between regions were quantified using rate ratios (RRs) and 95% confidence intervals (95% CIs). Temporal changes in SMM types and subtypes were described., Main Outcome Measures: Types and subtypes of SMM., Results: There were 59 789 SMM cases among 2 212 576 deliveries, corresponding to 270.2 (95% CI 268.1-272.4) per 10 000 deliveries. Composite SMM rates increased from 236.6 per 10 000 deliveries in 1999 to 307.3 per 10 000 deliveries in 2006, before declining to 253.8 per 10 000 deliveries in 2019. Changes in composite SMM corresponded with temporal changes in severe haemorrhage rates, which increased from 94.9 per 10 000 deliveries in 1999 to 169.3 per 10 000 deliveries in 2006, before declining to 111.2 per 10 000 deliveries in 2019. Severe pre-eclampsia, eclampsia and HELLP (haemolysis, elevated liver enzymes and low platelet count) syndrome (103.8 per 10 000 deliveries), severe haemorrhage (133.7 per 10 000 deliveries), sepsis, embolism, disseminated intravascular coagulation, shock and severe mental health disorders were the most common SMM types. Rates of embolism, disseminated intravascular coagulation and shock, acute renal failure, cardiac complications, sepsis and assisted ventilation increased, whereas rates of surgical complications, severe uterine rupture and anaesthesia complications declined., Conclusions: The observed spatiotemporal variations in composite SMM and SMM types provide substantive insights and highlight regional priorities for improving maternal health., (© 2023 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.)

Objectives: To quantify variation in the association between episiotomy and obstetric anal sphincter injury (OASI) by maternity care provider in spontaneous and operative vaginal deliveries (SVDs and OVDs)., Methods: Population-based retrospective cohort study of vaginal, term deliveries among nullipara in Canada (2004-2015). Adjusted rate ratios (ARRs) and 95% CIs were estimated using log-binomial regression to quantify the associations between episiotomy and OASI, stratified by care provider (obstetrician [OB], family physician [FP], or registered midwife [RM]) while adjusting for potential confounders., Results: The study included 631 642 deliveries. Episiotomy use varied by provider: among SVDs, the episiotomy rate was 19.6%, 14.4%, and 8.4% in the OB, FP, and RM groups, respectively. The rate of OASI was higher among SVDs with versus without episiotomy (5.8% vs 4.6%). Conversely, OASI occurred less frequently in operative vaginal deliveries with episiotomy (15.3%) compared with those without (16.7%). In all provider groups, the ARR for OASI was increased with episiotomy in SVD and decreased with episiotomy with forceps delivery. No differences in these associations were observed by provider except among vacuum delivery (ARR with episiotomy vs. without, OB: 0.88, 95% CI 0.84-0.92; FP: 0.89, 95% CI 0.83-0.96, RM: 1.22, 95% CI 1.02-1.48)., Conclusions: In nullipara, irrespective of maternity care provider, there is a positive association between episiotomy and OASI among SVDs and an inverse association between episiotomy and deliveries with forceps. The relationship between episiotomy and OASI is modified by maternity care providers among vacuum deliveries., (Copyright © 2024 The Author. Published by Elsevier Inc. All rights reserved.)

Background: National Vital Statistics System reports show that maternal mortality rates in the United States have nearly doubled, from 17.4 in 2018 to 32.9 per 100,000 live births in 2021. However, these high and rising rates could reflect issues unrelated to obstetrical factors, such as changes in maternal medical conditions or maternal mortality surveillance (eg, due to introduction of the pregnancy checkbox)., Objective: This study aimed to assess if the high and rising rates of maternal mortality in the United States reflect changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance., Study Design: The study was based on all deaths in the United States from 1999 to 2021. Maternal deaths were identified using the following 2 approaches: (1) per National Vital Statistics System methodology, as deaths in pregnancy or in the postpartum period, including deaths identified solely because of a positive pregnancy checkbox, and (2) under an alternative formulation, as deaths in pregnancy or in the postpartum period, with at least 1 mention of pregnancy among the multiple causes of death on the death certificate. The frequencies of major cause-of-death categories among deaths of female patients aged 15 to 44 years, maternal deaths, deaths due to obstetrical causes (ie, direct obstetrical deaths), and deaths due to maternal medical conditions aggravated by pregnancy or its management (ie, indirect obstetrical deaths) were quantified., Results: Maternal deaths, per National Vital Statistics System methodology, increased by 144% (95% confidence interval, 130-159) from 9.65 in 1999-2002 (n=1550) to 23.6 per 100,000 live births in 2018-2021 (n=3489), with increases occurring among all race and ethnicity groups. Direct obstetrical deaths increased from 8.41 in 1999-2002 to 14.1 per 100,000 live births in 2018-2021, whereas indirect obstetrical deaths increased from 1.24 to 9.41 per 100,000 live births: 38% of direct obstetrical deaths and 87% of indirect obstetrical deaths in 2018-2021 were identified because of a positive pregnancy checkbox. The pregnancy checkbox was associated with increases in less specific and incidental causes of death. For example, maternal deaths with malignant neoplasms listed as a multiple cause of death increased 46-fold from 0.03 in 1999-2002 to 1.42 per 100,000 live births in 2018-2021. Under the alternative formulation, the maternal mortality rate was 10.2 in 1999-2002 and 10.4 per 100,000 live births in 2018-2021; deaths from direct obstetrical causes decreased from 7.05 to 5.82 per 100,000 live births. Deaths due to preeclampsia, eclampsia, postpartum hemorrhage, puerperal sepsis, venous complications, and embolism decreased, whereas deaths due to adherent placenta, renal and unspecified causes, cardiomyopathy, and preexisting hypertension increased. Maternal mortality increased among non-Hispanic White women and decreased among non-Hispanic Black and Hispanic women. However, rates were disproportionately higher among non-Hispanic Black women, with large disparities evident in several causes of death (eg, cardiomyopathy)., Conclusion: The high and rising rates of maternal mortality in the United States are a consequence of changes in maternal mortality surveillance, with reliance on the pregnancy checkbox leading to an increase in misclassified maternal deaths. Identifying maternal deaths by requiring mention of pregnancy among the multiple causes of death shows lower, stable maternal mortality rates and declines in maternal deaths from direct obstetrical causes., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: There is uncertainty regarding the effect of the COVID-19 pandemic on population rates of stillbirth. We quantified pandemic-associated changes in stillbirth rates in Canada and the United States., Methods: We carried out a retrospective study that included all live births and stillbirths in Canada and the United States from 2015 to 2020. The primary analysis was based on all stillbirths and live births at ≥20 weeks gestation. Stillbirth rates were analyzed by month, with March 2020 considered to be the month of pandemic onset. Interrupted time series analyses were used to determine pandemic effects., Results: The study population included 18 475 stillbirths and 2 244 240 live births in Canada and 134 883 stillbirths and 22 963 356 live births in the United States (8.2 and 5.8 stillbirths per 1000 total births, respectively). In Canada, pandemic onset was associated with an increase in stillbirths at ≥20 weeks gestation of 1.01 (95% confidence interval [CI] 0.56-1.46) per 1000 total births and an increase in stillbirths at ≥28 weeks gestation of 0.35 (95% CI 0.16-0.54) per 1000 total births. In the United States, pandemic onset was associated with an increase in stillbirths at ≥20 weeks gestation of 0.48 (95% CI 0.22-0.75) per 1000 total births and an increase in stillbirths at ≥28 weeks gestation of 0.22 (95% CI 0.12-0.32) per 1000 total births. The increase in stillbirths at pandemic onset returned to pre-pandemic levels in subsequent months., Conclusion: The COVID-19 pandemic's onset was associated with a transitory increase in stillbirth rates in Canada and the United States., (Copyright © 2023 The Author. Published by Elsevier Inc. All rights reserved.)

Background: An increased risk for preterm birth has been observed among individuals with a previous second stage cesarean delivery when compared with those with a previous vaginal delivery. One mechanism that may contribute to the increased risk for preterm birth following a second stage cesarean delivery is the increased risk for cervical injury because of extension of the uterine incision (hysterotomy) into the cervix. The contribution of hysterotomy extension to the rate of preterm birth in a subsequent pregnancy has not been investigated and may shed light on the mechanism underlying the observed relationship between the mode of delivery and subsequent preterm birth., Objective: We aimed to quantify the association between unintended hysterotomy extension and preterm birth in a subsequent delivery., Study Design: We performed a retrospective cohort study using electronic perinatal data collected from 2 university-affiliated obstetrical centers. The study included patients with a primary cesarean delivery of a term, singleton live birth and a subsequent singleton birth in the same catchment (2005-2021). The primary outcome was subsequent preterm birth <37 weeks' gestation; secondary outcomes included subsequent preterm birth at <34, <32, and <28 weeks' gestation. We assessed crude and adjusted associations between unintended hysterotomy extensions and subsequent preterm birth with log binomial regression models using rate ratios and 95% confidence intervals. Adjusted models included several characteristics of the primary cesarean delivery such as maternal age, length of active labor, indication for cesarean delivery, chorioamnionitis, and maternal comorbidity., Results: A total 4797 patients met the study inclusion criteria. The overall rate of unintended hysterotomy extension in the primary cesarean delivery was 6.0% and the total rate of preterm birth in the subsequent pregnancy was 4.8%. Patients with an unintended hysterotomy extension were more likely to have a longer duration of active labor, chorioamnionitis, failed vacuum delivery attempt, second stage cesarean delivery, and persistent occiput posterior position of the fetal head in the primary cesarean delivery and higher rates of smoking in the subsequent pregnancy. Multivariable analyses that controlled for several confounders showed that a history of hysterotomy extension was not associated with a higher risk for preterm birth <37 weeks' gestation (adjusted rate ratio, 1.55; 95% confidence interval, 0.98-2.47), but it was associated with preterm birth <34 weeks' gestation (adjusted rate ratio, 2.49; 95% confidence interval, 1.06-5.42)., Conclusion: Patients with a uterine incision extension have a 2.5 times higher rate of preterm birth <34 weeks' gestation when compared with patients who did not have this injury. This association was not observed for preterm birth <37 weeks' gestation. Future research should aim to replicate our analyses with incorporation of additional data to minimize the potential for residual confounding., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Obesity increases risk of pre-eclampsia, but the association with haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome is understudied., Objective: To examine the association between prepregnancy body mass index (BMI) and HELLP syndrome, including early-onset versus late-onset disease., Study Design: A retrospective cohort study using population-based data., Setting: British Columbia, Canada, 2008/2009-2019/2020., Population: All pregnancies resulting in live births or stillbirths at ≥20 weeks' gestation., Methods: BMI categories (kg/m 2 ) included underweight (<18.5), normal (18.5-24.9), overweight (25.0-29.9) and obese (≥30.0). Rates of early-onset and late-onset HELLP syndrome (<34 vs ≥34 weeks, respectively) were calculated per 1000 ongoing pregnancies at 20 and 34 weeks' gestation, respectively. Cox regression was used to assess the associations between risk factors (eg, BMI, maternal age and parity) and early-onset versus late-onset HELLP syndrome., Main Outcome Measures: Early-onset and late-onset HELLP syndrome., Results: The rates of HELLP syndrome per 1000 women were 2.8 overall (1116 cases among 391 941 women), and 1.9, 2.5, 3.2 and 4.0 in underweight, normal BMI, overweight and obese categories, respectively. Overall, gestational age-specific rates of HELLP syndrome increased with prepregnancy BMI. Obesity (compared with normal BMI) was more strongly associated with early-onset HELLP syndrome (adjusted HR (AHR) 2.24 (95% CI 1.65 to 3.04) than with late-onset HELLP syndrome (AHR 1.48, 95% CI 1.23 to 1.80) (p value for interaction 0.025). Chronic hypertension, multiple gestation, bleeding (<20 weeks' gestation and antepartum) also showed differing AHRs between early-onset versus late-onset HELLP syndrome., Conclusions: Prepregnancy BMI is positively associated with HELLP syndrome and the association is stronger with early-onset HELLP syndrome. Associations with early-onset and late-onset HELLP syndrome differed for some risk factors, suggesting possible differences in aetiological mechanisms., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: This study aimed to quantify the association between mode of operative delivery in the second stage of labor (cesarean delivery vs operative vaginal delivery) and spontaneous preterm birth in a subsequent pregnancy., Data Sources: MEDLINE, Embase, EmCare, CINAHL, the Cochrane Library, Web of Science: Core Collection, and Scopus were searched from database inception to April 1, 2023., Study Eligibility Criteria: All retrospective cohort studies with participants who had a second-stage cesarean delivery (defined as intrapartum cesarean delivery at full cervical dilation) or operative vaginal delivery (including forceps- and/or vacuum-assisted delivery) and that reported the rate of preterm birth (either spontaneous or not specified) in subsequent pregnancy were included., Methods: Both a descriptive analysis and a meta-analysis were performed. A meta-analysis was performed for dichotomous data using the Mantel-Haenszel random-effects model and used the odds ratio as an effect measure with 95% confidence intervals. The risk of bias was assessed using Cochrane's 2022 Risk Of Bias In Non-randomized Studies of Exposure tool., Results: After screening 2671 articles from 7 databases, a total of 18 retrospective cohort studies encompassing 605,138 patients were included. The pooled rates of spontaneous preterm birth in a subsequent pregnancy were 6.9% (12 studies) after second-stage cesarean delivery and 2.6% (8 studies) after operative vaginal delivery. A total of 7 studies encompassing 75,460 patients compared the primary outcome of spontaneous preterm birth after second-stage cesarean delivery vs operative vaginal delivery in an index pregnancy with an odds ratio of 2.01 (95% confidence interval, 1.57-2.58) in favor of operative vaginal delivery. However, most studies did not include important confounding factors, did not address exposure misclassification because of failed operative vaginal delivery, and considered operative vaginal delivery as a homogeneous category with no distinction between forceps- and vacuum-assisted deliveries., Conclusion: Although a synthesis of the existing literature suggests that the risk of spontaneous preterm birth is higher in those with a previous second-stage cesarean delivery than in those with operative vaginal delivery, the risk of bias in these studies is very high. Findings should be interpreted with caution., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Obstetrical anal sphincter injury describes a severe injury to the perineum and perianal muscles after birth. Obstetrical anal sphincter injury occurs in approximately 4.4% of vaginal births in the United States; however, racial and ethnic inequities in the incidence of obstetrical anal sphincter injury have been shown in several high-income countries. Specifically, an increased risk of obstetrical anal sphincter injury in individuals who identify as Asian vs those who identify as White has been documented among residents of the United States, Australia, Canada, Western Europe, and the Scandinavian countries. The high rates of obstetrical anal sphincter injury among the Asian diaspora in these countries are higher than obstetrical anal sphincter injury rates reported among Asian populations residing in Asia. A systematic review and meta-analysis of studies in high-income, non-Asian countries was conducted to further evaluate this relationship., Data Sources: MEDLINE, Ovid, Embase, EmCare, and the Cochrane databases were searched from inception to March 2023 for original research studies., Study Eligibility Criteria: Observational studies using keywords and controlled vocabulary terms related to race, ethnicity and obstetrical anal sphincter injury. All observational studies, including cross-sectional, case-control, and cohort were included. 2 reviewers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Meta-analysis of Observational Studies in Epidemiology recommendations., Methods: Meta-analysis was performed using RevMan (version 5.4; Cochrane Collaboration, London, United Kingdom) for dichotomous data using the random effects model and the odds ratios as effect measures with 95% confidence intervals. Subgroup analysis was performed among Asian subgroups. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tools. Meta-regression was used to determine sources of between-study heterogeneity., Results: A total of 27 studies conducted in 7 countries met the inclusion criteria encompassing 2,337,803 individuals. The pooled incidence of obstetrical anal sphincter injury was higher among Asian individuals than White individuals (pooled odds ratio, 1.64; 95% confidence interval, 1.48-1.80). Subgroup analyses showed that obstetrical anal sphincter injury rates were highest among South Asians and among population-based vs hospital-based studies. Meta-regression showed that moderate heterogeneity remained even after accounting for differences in studies by types of Asian subgroups included, study year, mode of delivery included, and study setting., Conclusion: Obstetrical anal sphincter injury is more frequent among Asian versus white birthing individuals in multiple high-income, non-Asian countries. Qualitative and quantitative research to elucidate underlying causal mechanisms responsible for this relationship are warranted., (© 2023 The Authors.)

Objective: To quantify pandemic-related changes in obstetric intervention and perinatal outcomes in the United States., Methods: We carried out a retrospective study of all live births and fetal deaths in the United States, 2015-2021, with data obtained from the natality, fetal death, and linked live birth-infant death files of the National Center for Health Statistics. Analyses were carried out among all singletons; singletons of patients with prepregnancy diabetes, prepregnancy hypertension, and hypertensive disorders of pregnancy; and twins. Outcomes of interest included preterm birth, preterm labor induction or preterm cesarean delivery, macrosomia, postterm birth, and perinatal death. Interrupted time series analyses were used to estimate changes in the prepandemic period (January 2015-February 2020), at pandemic onset (March 2020), and in the pandemic period (March 2020-December 2021)., Results: The study population included 26,604,392 live births and 155,214 stillbirths. The prepandemic period was characterized by temporal increases in preterm birth and preterm labor induction or cesarean delivery rates and temporal reductions in macrosomia, postterm birth, and perinatal mortality. Pandemic onset was associated with absolute decreases in preterm birth (decrease of 0.322/100 live births, 95% CI 0.506-0.139) and preterm labor induction or cesarean delivery (decrease of 0.190/100 live births, 95% CI 0.334-0.047) and absolute increases in macrosomia (increase of 0.046/100 live births), postterm birth (increase of 0.015/100 live births), and perinatal death (increase of 0.501/1,000 total births, 95% CI 0.220-0.783). These changes were larger in subpopulations at high risk (eg, among singletons of patients with prepregnancy diabetes). Among singletons of patients with prepregnancy diabetes, pandemic onset was associated with a decrease in preterm birth (decrease of 1.634/100 live births) and preterm labor induction or cesarean delivery (decrease of 1.521/100 live births) and increases in macrosomia (increase of 0.328/100 live births) and perinatal death (increase of 9.840/1,000 total births, 95% CI 3.933-15.75). Most changes were reversed in the months after pandemic onset., Conclusion: The onset of the coronavirus disease 2019 (COVID-19) pandemic was associated with a transient decrease in obstetric intervention (especially preterm labor induction or cesarean delivery) and a transient increase in perinatal mortality., Competing Interests: Financial Disclosure Amelie Boutin reports receiving a Junior I Research Scholar Award from a governmental agency, the Fonds de recherche du Québec-Santé. Mohamed A. Bedaiwy disclosed receiving funding from Pfizer, and his institution received funding from Ferring. He also received a grant from CIHR to study the effects of COVID on patients with recurrent pregnancy loss. The other authors did not report any potential conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Preterm birth is an important outcome or exposure in epidemiologic research. When administrative data on measured gestational age is not available, parent-reported gestational age can be obtained from questionnaires, which is subject to potential bias. To our knowledge, few studies have assessed the validity of parent-reported gestational age categories, including commonly defined categories of preterm birth., Methods: We used linked data from primarily healthy children <6 years of age in TARGet Kids! in Toronto, Canada, and ICES administrative healthcare data from April 2011 to March 2020. We assessed the criterion validity of questionnaire-based parent-reported gestational age by calculating sensitivity and specificity for term (≥37 weeks), late preterm (34-36 weeks), and moderately preterm (32-33 weeks) gestational age categories, using administrative healthcare records of gestational age as the criterion standard. We conducted subgroup analyses for various parent and socioeconomic factors that may influence recall., Results: Of the 4684 participants, 97.3% correctly classified the gestational age category according to administrative healthcare data. Parent-reported gestational age sensitivity ranged from 83.7% to 98.5% and specificity ranged from 88.3% to 99.8%, depending on category. For each subgroup characteristic, sensitivity and specificity were all ≥70%. Lower educational attainment, lower family income, father reporting, ≥1 year since birth, ≥2 children, lower parent age, and reported gestational diabetes and/or hypertension were associated with slightly lower sensitivity and/or specificity., Conclusions: In this linked cohort, parent-reported gestational age categories had high accuracy. Criterion validity varied minimally among some parent and socioeconomic factors. Our findings can inform future quantitative bias analyses., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Competing Interests: Competing interests: We have read and understood the BMJ policy on declaration of interests and have no interests to declare.

Background: Obstetric anal sphincter injury (OASI) describes severe injury to the perineum and perineum and perianal muscles following birth and occurs in 4.4% to 6.0% of vaginal births in Canada. Studies from high-income countries have identified an increased risk of OASI in individuals who identify as Asian race versus those who identify as white. This protocol outlines a systematic review and meta-analysis which aims to determine the incidence of OASI in individuals living in high-income countries who identify as Asian versus those of white race/ethnicity. We hypothesize that the pooled incidence of OASI will be higher in Asian versus white birthing individuals., Methods: We will search MEDLINE, OVID, Embase, Emcare and Cochrane databases from inception to 2022 for observational studies using keywords and controlled vocabulary terms related to race, ethnicity and OASI. Two reviewers will follow the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and Meta-analysis of Observational Studies (MOOSE) recommendations. Meta-analysis will be performed using RevMan for dichotomous data using the random effects model and the odds ratio (OR) as effect measure with a 95% confidence interval (CI). Subgroup analysis will be performed based on Asian subgroups (e.g., South Asian, Filipino, Chinese, Japanese individuals). Study quality assessment will be performed using The Joanna Briggs Institute Critical Appraisal tools., Discussion: The systematic review and meta-analysis that this protocol outlines will synthesize the extant literature to better estimate the rates of OASI in Asian and white populations in non-Asian, high-income settings and the relative risk of OASI between these two groups. This systematic summary of the evidence will inform the discrepancy in health outcomes experienced by Asian and white birthing individuals. If these findings suggest a disproportionate burden among Asians, they will be used to advocate for future studies to explore the causal mechanisms underlying this relationship, such as differential care provision, barriers to accessing care, and social and institutional racism. Ultimately, the findings of this review can be used to frame obstetric care guidelines and inform healthcare practices to ensure care that is equitable and accessible to diverse populations., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Park et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: To investigate the effect of maternal stature on adverse birth outcomes and quantify perinatal risks associated with small- and large-for-gestational age infants (SGA and LGA, respectively) born to mothers of short, average, and tall stature., Design: Retrospective cohort study., Setting: USA, 2016-2017., Population: Women with a singleton live birth (N = 7 325 741)., Methods: Using data from the National Center for Health Statistics, short and tall stature were defined as <10th and >90th centile of the maternal height distribution. Modified Poisson regression was used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (95% CIs)., Main Outcome Measures: Preterm birth (<37 weeks of gestation), neonatal intensive care unit (NICU) admission and severe neonatal morbidity/mortality (SNMM)., Results: With increased maternal height, the risk of adverse outcomes increased in SGA infants and decreased in LGA infants compared with infants appropriate-for-gestational age (AGA) (p < 0.001). Infants who were SGA born to women of tall stature had the highest risk of NICU admission (aRR 1.98, 95% CI 1.91-2.05; p < 0.001), whereas LGA infants born to women of tall stature had the lowest risk (aRR 0.85, 95% CI 0.82-0.88; p < 0.001), compared with AGA infants born to women of average stature. LGA infants born to women of short stature had an increased risk of NICU admission and SNMM, compared with AGA infants born to women of average stature (aRR 1.32, 95% CI 1.27-1.38; aRR 1.21, 95% CI 1.13-1.29, respectively)., Conclusions: Maternal height modifies the association between SGA and LGA status at birth and neonatal outcomes. This quantification of risk can assist healthcare providers in monitoring fetal growth, and optimising neonatal care and follow-up., (© 2022 John Wiley & Sons Ltd.)

Background: There are known differences in the risk of perinatal and maternal birth outcomes because of maternal factors, such as body mass index and maternal race. However, the association of maternal height with adverse birth outcomes and the potential differences in this relationship by race and ethnicity have been understudied., Objective: This study aimed to examine the association between maternal stature and adverse perinatal outcomes and the potential modification of the association by race and ethnicity., Study Design: This retrospective cohort study was conducted using data on all singleton births in the United States in 2016 and 2017 (N=7,361,713) obtained from the National Center for Health Statistics. Short and tall stature were defined as <10th and >90th percentiles of the maternal height distribution (<154.9 and >172.7 cm, respectively). Race and ethnicity categories included non-Hispanic White, non-Hispanic Black, American Indian or Alaskan Native Asian or Pacific Islander, and Hispanic. The primary outcomes were preterm birth (<37 weeks of gestation), perinatal death, and composite perinatal death or severe neonatal morbidity. Logistic regression was used to obtain adjusted odds ratios and 95% confidence intervals with adjustment for confounding by maternal age, body mass index, and other factors. Multiplicative and additive effect modifications by race and ethnicity were assessed., Results: The study population included 7,361,713 women with a singleton stillbirth or live birth. Short women had an increased risk of adverse outcomes, whereas tall women had a decreased risk relative to average-stature women. Short women had an increased risk of perinatal death and composite perinatal death or severe neonatal morbidity (adjusted odds ratios, 1.14 [95% confidence interval, 1.10-1.17] and 1.21 [95% confidence interval, 1.19-1.23], respectively). The association between short stature and perinatal death was attenuated in non-Hispanic Black women compared with non-Hispanic White women (adjusted odds ratio, 1.10 [95% confidence interval, 1.03-1.17] vs 1.26 [95% confidence interval, 1.19-1.33]). Compared with average-stature women, tall non-Hispanic White women had lower rates of preterm birth, perinatal death, and composite perinatal death or severe neonatal morbidity (adjusted odds ratios, 0.82 [95% confidence interval, 0.81-0.83], 0.95 [95% confidence interval, 0.91-1.00], and 0.90 [95% confidence interval, 0.88-0.93], respectively). The association between tall and average stature with perinatal death was reversed in Hispanic women (adjusted odds ratio, 1.27; 95% confidence interval, 1.12-1.44). Compared with average-stature women, all tall women had lower rates of preterm birth, particularly among non-Hispanic Black and Hispanic women., Conclusion: Relative to average-stature women, short women have an increased risk of adverse perinatal outcomes across all race and ethnicity groups; these associations were attenuated in Hispanic women and for some adverse outcomes in non-Hispanic Black and Asian women. Tall mothers have a lower risk of preterm birth in all racial and ethnic groups, whereas tall non-Hispanic White mothers have a lower risk of perinatal death or severe neonatal morbidity compared with average-stature women., (© 2023 The Authors.)

Background: High prepregnancy body mass index is one of the most common risk factors for adverse perinatal events., Objective: This study aimed to assess whether the association between maternal body mass index and adverse perinatal outcome is modified by other concomitant maternal risk factors., Study Design: This was a retrospective cohort study of all singleton live births and stillbirths in the United States from 2016 to 2017, using data from the National Center for Health Statistics. Logistic regression was used to estimate the adjusted odds ratios and 95% confidence intervals between prepregnancy body mass index and a composite outcome of stillbirth, neonatal death, and severe neonatal morbidity. Modification of this association by maternal age, nulliparity, chronic hypertension, and prepregnancy diabetes mellitus was assessed on both multiplicative and additive scales., Results: The study population included 7,576,417 women with singleton pregnancy; 254,225 (3.5%) were underweight, 3,220,432 (43.9%) had normal body mass index, 1,918,480 (26.1%) were overweight, and 1,062,177 (14.4%), 516,693 (7.0%), and 365,357 (5.0%) had class I, II, and III obesity, respectively. Rates of the composite outcome increased with increasing body mass index above normal values, compared with women with normal body mass index. Nulliparity (289,776; 38.6%), chronic hypertension (135,328; 1.8%), and prepregnancy diabetes mellitus (67,744; 0.89%) modified the association between body mass index and the composite perinatal outcome on both the additive and multiplicative scales. Nulliparous (vs parous) women had a higher rate of increase in adverse outcomes with increasing body mass index. For example, in nulliparous women, class III obesity was associated with 1.8-fold higher odds compared with normal body mass index (adjusted odds ratio, 1.77; 95% confidence interval, 1.73-1.83), whereas in parous women, the adjusted odds ratio was 1.35 (95% confidence interval, 1.32-1.39). Women with chronic hypertension or prepregnancy diabetes mellitus had higher outcome rates overall; however, the dose-response relationship with increasing body mass index was absent. Although the composite outcome rates increased with maternal age, the risk curves were relatively similar across obesity classes in all maternal age groups. Overall, underweight women had 7% higher odds of the composite outcome, and this increased to 21% in parous women., Conclusion: Women with elevated prepregnancy body mass index are at increased risk of adverse perinatal outcomes, and the magnitude of these risks differs by concomitant risk factors, including prepregnancy diabetes mellitus, chronic hypertension, and nulliparity. In particular, in woman with chronic hypertension or prepregnancy diabetes mellitus, there is no impact of increasing body mass index on adverse perinatal outcomes. However, overall rates remain high, and prepregnancy prevention of hypertension and diabetes mellitus should be emphasized among all women irrespective of body mass index., (© 2023 The Authors.)

Background: Recommendations for deliveries of pregnant patients with a previous cesarean delivery and the type of hospitals deemed safe for these deliveries have evolved in recent years, although no studies have examined hospital factors and associated safety. We sought to evaluate maternal and neonatal outcomes among patients with a previous cesarean delivery by hospital tier and volume., Methods: We carried out an ecological study of singleton live births delivered at term gestation to patients with a previous cesarean delivery in all Canadian hospitals (excluding Quebec), 2013-2019. We obtained data from the Discharge Abstract Database of the Canadian Institute for Health Information. The primary outcomes were severe maternal morbidity or mortality (SMMM), and serious neonatal morbidity or mortality (SNMM). We used regression modelling to examine hospital tier (tier 4 hospitals being those that provide the highest level of care) and volume; we also identified hospitals with high rates of SMMM and SNMM using within-tier comparisons and comparisons with the overall rate., Results: We included 235 442 deliveries to patients with a previous cesarean delivery; SMMM and SNMM rates were 14.6 per 1000 deliveries and 4.6 per 1000 live births, respectively. Among patients with a parity of 1, SMMM rates were lower in tier 1 hospitals (adjusted incidence rate ratio [IRR] 0.68, 95% confidence interval [CI] 0.52-0.89) and higher in tier 4 hospitals (adjusted IRR 1.41, 95% CI 1.05-1.91) than in tier 2 hospitals; SNMM rates did not differ by hospital tier. Rates of SNMM increased with increasing hospital volume (adjusted IRR 1.02, 95% CI 1.00-1.04) and increasing rates of vaginal birth after cesarean delivery (adjusted IRR 1.02, 95% CI 1.01-1.04). Most hospitals had relatively low SMMM and SNMM rates, although a few hospitals in each tier and volume category had significantly higher rates than others., Interpretation: Adverse maternal and neonatal outcomes among patients with a previous cesarean delivery showed no clear pattern of decreasing SMMM and SNMM with increasing tiers of service and hospital volume. All hospitals, irrespective of tier or size, should continually review their rates of adverse maternal and neonatal outcomes., Competing Interests: Competing interests: Carmen Young reports a role as region 1 representative with the maternal–fetal medicine specialty committee of the Royal College of Physicians and Surgeons of Canada. Douglas Wilson reports a role as president of the Society of Obstetricians and Gynaecologists of Canada., (© 2023 CMA Impact Inc. or its licensors.)

Background: The initial COVID-19 pandemic response-related effects on conceptions following the use of assisted reproductive technologies (ART), and on changes in the maternal characteristics of women who conceived during the early vs. pre-pandemic period, have been understudied., Objectives: To examine the effects of ART clinic closures in the United States (US) in March 2020 on the frequency of ART-conceived live births, multiple births and stillbirths; and to describe changes in the characteristics of women who conceived in the early pandemic period., Methods: Population-based cohort study including all births in the US from January 2015 to December 2020 (22,907,688 live births; 134,537 stillbirths). Interrupted time series (ITS) methodology was used to estimate rate ratios (RR) of expected versus observed rates in December 2020 (i.e., among births conceived mainly in March 2020). Demographic and clinical characteristics were compared between mothers who conceived in March 2020 versus March 2015-2019., Results: Overall, 1.1% of live births and 1.7% of stillbirths were conceived by ART. ART-conceived live births decreased by 57.0% in December 2020 (observed vs. expected RR 0.43, 95% confidence interval [CI] 0.40, 0.45), and these declines occurred in all subgroups of women. Multiple births also declined in December 2020. Stillbirth rates increased in December 2020 in ART-conceived births (RR 2.55, 95% CI 1.63, 3.92) but remained unchanged in the non-ART group. Maternal characteristics of women who conceived in the early pandemic versus pre-pandemic period differed and included an increased prevalence of pre-pregnancy obesity class 3 and chronic hypertension., Conclusions: The early pandemic closure of ART clinics resulted in a substantial decline in ART-conceived live births and multiple births in December 2020 and an increase in the proportion of stillbirths among ART-conceived births. Women who conceived in the early pandemic period also had an increased prevalence of obesity and chronic hypertension., (© 2022 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd.)

Background and Objectives: Although racial and ethnic disparities in adverse birth outcomes have been well documented, it is unknown whether such disparities diminish in women who use medically assisted reproduction (MAR). We examined differences in the association between maternal race and ethnicity and adverse birth outcomes among women who conceived spontaneously and those who used MAR, including assisted reproduction technology (ART), eg, in-vitro fertilization, and also non-ART MAR, eg, fertility drugs., Methods: We conducted a population-based retrospective cohort study using data on all singleton births (N = 7 545 805) in the United States from 2016 to 2017. The outcomes included neonatal and fetal death, preterm birth, and serious neonatal morbidity, among others. Modified Poisson regression was used to estimate adjusted rate ratios (aRR) and 95% confidence intervals (CI) and to assess the interactions between race and ethnicity and mode of conception., Results: Overall, 93 469 (1.3%) singletons were conceived by MAR. Neonatal mortality was twofold higher among infants of non-Hispanic Black versus non-Hispanic White women in the spontaneous-conception group (aRR = 1.9, 95% CI: 1.8-1.9), whereas in the ART-conception group, neonatal mortality was more than fourfold higher in infants of non-Hispanic Black women (aRR = 4.1, 95% CI: 2.9-5.9). Racial and ethnic disparities between Hispanic versus non-Hispanic White women were also significantly larger among women who conceived using MAR with regard to preterm birth (&lt;34 weeks) and perinatal mortality., Conclusions: Compared to women who conceived spontaneously, racial and ethnic disparities in adverse perinatal outcomes were larger in women who used MAR. More research is needed to identify preventive measures for reducing risks among vulnerable women who use medically assisted reproduction., (Copyright © 2022 by the American Academy of Pediatrics.)

Background: The Robson classification has become a global standard for comparing and monitoring cesarean delivery (CD) rates across populations and over time; however, this classification does not account for differences in important maternal, fetal, and obstetric practice factors known to impact CD rates. The objectives of our study were to identify subgroups of women contributing to differences in the CD rate in Sweden and British Columbia (BC), Canada using the Robson classification and to estimate the contribution of maternal, fetal/infant, and obstetric practice factors to differences in CD rates between countries and over time., Methods and Findings: We conducted a population-based cohort study of deliveries in Sweden (January 1, 2004 to December 31, 2016; n = 1,392,779) and BC (March 1, 2004 to April 31, 2017; n = 559,205). Deliveries were stratified into Robson categories and the CD rate, relative size of each group and its contribution to the overall CD rate were compared between the Swedish and the Canadian cohorts. Poisson and log-binomial regression were used to assess the contribution of maternal, fetal, and obstetric practice factors to spatiotemporal differences in Robson group-specific CD rates between Sweden and BC. Nulliparous women comprised 44.8% of the study population, while women of advanced maternal age (≥35 years) and women with overweight/obesity (≥25 kg/m2) constituted 23.5% and 32.4% of the study population, respectively. The CD rate in Sweden was stable at approximately 17.0% from 2004 to 2016 (p for trend = 0.10), while the CD rate increased in BC from 29.4% to 33.9% (p for trend < 0.001). Differences in CD rates between Sweden and BC varied by Robson group, for example, in Group 1 (nullipara with a term, single, cephalic fetus with spontaneous labor), the CD rate was 8.1% in Sweden and 20.4% in BC (rate ratio [RR] for BC versus Sweden = 2.52, 95% confidence interval [CI] 2.49 to 2.56, p < 0.001) and in Group 2 (nullipara, single, cephalic fetus, term gestation with induction of labor or prelabor CD), the rate of CD was 37.3% in Sweden and 45.9% in BC (RR = 1.23, 95% CI 1.22 to 1.25, p < 0.001). The effect of adjustment for maternal characteristics (e.g., age, body mass index), maternal comorbidity (e.g., preeclampsia), fetal characteristics (e.g., head position), and obstetric practice factors (e.g., epidural) ranged from no effect (e.g., among breech deliveries; Groups 6 and 7) to explaining up to 5.2% of the absolute difference in the CD rate (Group 2: adjusted CD rate in BC 40.7%, adjusted RR = 1.09, 95% CI 1.08 to 1.12, p < 0.001). Adjustment also explained a substantial fraction of the temporal change in CD rates among some Robson groups in BC. Limitations of the study include a lack of information on intrapartum details, such as labor duration as well as maternal and perinatal outcomes associated with the observed differences in CD rates., Conclusions: In this study, we found that several factors not included in the Robson classification explain a significant proportion of the spatiotemporal difference in CD rates in some Robson groups. These findings suggest that incorporating these factors into explanatory models using the Robson classification may be useful for ensuring that public health initiatives regarding CD rates are evidence informed., Competing Interests: The authors have declared that no competing interests exist.

Background: The most important knowledge gap in connection with obstetric management for time of delivery in term low-risk pregnancies relates to the absence of information on long-term neurodevelopmental outcomes., Objectives: We examined risks of stillbirth, infant mortality, cerebral palsy (CP) and epilepsy among low-risk pregnancies., Methods: In this population-based Swedish study, we identified, from 1998 to 2019, 1,773,269 singleton infants born between 37 and 42 completed weeks in women with low-risk pregnancies. Poisson log-linear regression models were used to examine the association between gestational age at delivery and stillbirth, infant mortality, CP and epilepsy. Adjusted rate ratios (RR) and 95% confidence intervals expressing the effect of birth at a particular gestational week compared with birth at a later gestational week were estimated., Results: Compared with those born at a later gestation, RRs for stillbirth and infant mortality were higher among births at 37 weeks' and 38 weeks' gestation. The RRs for infant mortality were approximately 20% and 25% lower among births at 40 or 41 weeks compared with those born at later gestation, respectively. Infants born at 37 and 38 weeks also had higher RRs for CP (vs infants born at ≥38 and ≥39 weeks, respectively), while those born at 39 gestation had similar RRs (vs infants born at ≥40 weeks); infants born at 40 and 41 weeks had lower RRs of CP (vs those born at ≥41 and 42 weeks, respectively). The RRs for epilepsy were higher in those born at 37 and 38 weeks compared with those born at later gestation., Conclusions: Among low-risk pregnancies, birth at 37 or 38 completed weeks' gestation is associated with increased risks of stillbirth, infant mortality and neurological morbidity, while birth at 39-40 completed weeks is associated with reduced risks compared with births at later gestation., (© 2022 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd.)

Background: Operative vaginal delivery (OVD) is considered safe if carried out by trained personnel. However, opportunities for training in OVD have declined and, given these shifts in practice, the safety of OVD is unknown. We estimated incidence rates of trauma following OVD in Canada, and quantified variation in trauma rates by instrument, region, level of obstetric care and institutional OVD volume., Methods: We conducted a cohort study of all singleton, term deliveries in Canada between April 2013 and March 2019, excluding Quebec. Our main outcome measures were maternal trauma (e.g., obstetric anal sphincter injury, high vaginal lacerations) and neonatal trauma (e.g., subgaleal hemorrhage, brachial plexus injury). We calculated adjusted and stabilized rates of trauma using mixed-effects logistic regression., Results: Of 1 326 191 deliveries, 38 500 (2.9%) were attempted forceps deliveries and 110 987 (8.4%) were attempted vacuum deliveries. The maternal trauma rate following forceps delivery was 25.3% (95% confidence interval [CI] 24.8%-25.7%) and the neonatal trauma rate was 9.6 (95% CI 8.6-10.6) per 1000 live births. Maternal and neonatal trauma rates following vacuum delivery were 13.2% (95% CI 13.0%-13.4%) and 9.6 (95% CI 9.0-10.2) per 1000 live births, respectively. Maternal trauma rates remained higher with forceps than with vacuum after adjustment for confounders (adjusted rate ratio 1.70, 95% CI 1.65-1.75) and varied by region, but not by level of obstetric care., Interpretation: In Canada, rates of trauma following OVD are higher than previously reported, irrespective of region, level of obstetric care and volume of OVD among hospitals. These results support a reassessment of OVD safety in Canada., Competing Interests: Competing interests: Michael Kramer reports funding from the Canadian Institutes of Health Research and the Family Rosenquist Foundation, outside the submitted work. He also reports participation on the data safety monitoring board of the MOBYDick clinical trial and on the scientific advisory board of the Family Rosenquist Foundation., (© 2022 CMA Impact Inc. or its licensors.)

Background: The majority of previous studies on severe preeclampsia, eclampsia, and hemolysis, elevated liver enzymes, and low platelet count syndrome were hospital-based or included a relatively small number of women. Large, population-based studies examining gestational age-specific incidence patterns and risk factors for these severe pregnancy complications are lacking., Objective: This study aimed to assess the gestational age-specific incidence rates and risk factors for severe preeclampsia, hemolysis, elevated liver enzymes, and low platelet count syndrome, and eclampsia., Study Design: We carried out a retrospective, population-based cohort study that included all women with a singleton hospital birth in Canada (excluding Quebec) from 2012 to 2016 (N=1,078,323). Data on the primary outcomes (ie, severe preeclampsia, hemolysis, elevated liver enzymes, and low platelet count syndrome, and eclampsia) were obtained from delivery hospitalization records abstracted by the Canadian Institute for Health Information. A Cox regression was used to assess independent risk factors (eg, maternal age and chronic comorbidity) for each primary outcome and to assess differences in the effects at preterm vs term gestation (<37 vs ≥37 weeks)., Results: The rates of severe preeclampsia (n=2533), hemolysis, elevated liver enzymes, and low platelet count syndrome (n=2663), and eclampsia (n=465) were 2.35, 2.47, and 0.43 per 1000 singleton pregnancies, respectively. The cumulative incidence of term-onset severe preeclampsia was lower than that of preterm-onset severe preeclampsia (0.87 vs 1.54 per 1000; rate ratio, 0.57; 95% confidence intervals, 0.53-0.62), the rates of hemolysis, elevated liver enzymes, and low platelet count syndrome were similar (1.32 vs 1.23 per 1000; rate ratio, 0.93; 95% confidence interval, 0.86-1.00), and the preterm-onset eclampsia rate was lower than the term-onset rate (0.12 vs 0.33 per 1000; rate ratio, 2.64; 95% confidence interval, 2.16-3.23). For each primary outcome, chronic comorbidity and congenital anomalies were stronger risk factors for preterm- vs term-onset disease. Younger mothers (aged <25 years) were at higher risk for severe preeclampsia at term and for eclampsia at all gestational ages, whereas older mothers (aged ≥35 years) had elevated risks for severe preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome. Regardless of gestational age, nulliparity was a risk factor for all outcomes, whereas socioeconomic status was inversely associated with severe preeclampsia., Conclusion: The risk for severe preeclampsia declined at term, eclampsia risk increased at term, and hemolysis, elevated liver enzymes, and low platelet count syndrome risk was similar for preterm and term gestation. Young maternal age was associated with an increased risk for eclampsia and term-onset severe preeclampsia. Prepregnancy comorbidity and fetal congenital anomalies were more strongly associated with severe preeclampsia, hemolysis, elevated liver enzymes, and low platelet count syndrome, and eclampsia at preterm gestation., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Several studies of prenatal determinants and neonatal morbidity and mortality among very preterm births have resulted in unexpected and paradoxical findings. We aimed to compare perinatal death rates among cohorts of very preterm births (24-31 weeks) with rates among all births in these groups (≥24 weeks), using births-based and fetuses-at-risk formulations., Methods: We conducted a cohort study of singleton live births and stillbirths ≥24 weeks' gestation using population-based data from the United States and Canada (2006-2015). We contrasted rates of perinatal death between women with or without hypertensive disorders, between maternal races, and between births in Canada vs the United States., Results: Births-based perinatal death rates at 24-31 weeks were lower among hypertensive than among non-hypertensive women (rate ratio [RR] 0.67, 95% CI 0.65-0.68), among Black mothers compared with White mothers (RR 0.94, 95%CI 0.92-0.95) and among births in the United States compared with Canada (RR 0.74, 95%CI 0.71-0.75). However, overall (≥24 weeks) perinatal death rates were higher among births to hypertensive vs non-hypertensive women (RR 2.14, 95%CI 2.10-2.17), Black vs White mothers (RR 1.86, 95%CI 184-1.88;) and births in the United States vs Canada (RR 1.08, 95%CI 1.05-1.10), as were perinatal death rates based on fetuses-at-risk at 24-31 weeks (RR for hypertensive disorders: 2.58, 95%CI 2.53-2.63; RR for Black vs White ethnicity: 2.29, 95%CI 2.25-2.32; RR for United States vs Canada: 1.27, 95%CI 1.22-1.30)., Conclusion: Studies of prenatal risk factors and between-centre or between-country comparisons of perinatal mortality bias causal inferences when restricted to truncated cohorts of very preterm births., Competing Interests: The authors have declared that no competing interests exist.

Rigorous studies carried out by the National Center for Health Statistics show that previously reported increases in maternal mortality rates in the United States were an artifact of changes in surveillance. The pregnancy checkbox, introduced in the revised 2003 death certificate and implemented by the states in a staggered manner, resulted in increased identification of maternal deaths and in reported maternal mortality rates. This Commentary summarizes the findings of the National Center for Health Statistics reports, describes temporal trends and the current status of maternal mortality in the United States, and discusses future concerns. Although the National Center for Health Statistics studies, based on recoding of death certificate information (after excluding information from the pregnancy checkbox), showed that crude maternal mortality rates did not change significantly between 2002 and 2018, age-adjusted analyses show a temporal reduction in the maternal mortality rate (21% decline, 95% CI 13-28). Specific causes of maternal death, which were not affected by the pregnancy checkbox, such as preeclampsia, showed substantial temporal declines. However, large racial disparities continue to exist: Non-Hispanic Black women had a 2.5-fold higher maternal mortality rate compared with non-Hispanic White women in 2018. This overview of maternal mortality underscores the need for better surveillance and more accurate identification of maternal deaths, improved clinical care, and expanded public health initiatives to address social determinants of health. Challenges with ascertaining maternal deaths notwithstanding, several causes of maternal death (unaffected by surveillance artifacts) show significant temporal declines, even though there remains substantial scope for preventing avoidable maternal death and reducing disparities., Competing Interests: Financial Disclosure The authors did not report any potential conflicts of interest., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: Postpartum hemorrhage (PPH) is recognized as a leading cause of obstetric morbidity and mortality. Population-wide studies have used International Classification of Diseases (ICD) diagnostic codes to track and report the prevalence of PPH. Although the 10th revision (ICD-10) was introduced in Sweden in 1997, the accuracy of ICD-10 codes for PPH is not known. Thus, the aim was to determine the accuracy of diagnostic coding for PPH in the Swedish Pregnancy Register., Material and Methods: We performed a retrospective cohort study of 609 807 deliveries in Sweden between 2014 and 2019. Information on ICD-10 codes for PPH and estimated blood loss were extracted from the Swedish Pregnancy Register. Using an estimated blood loss >1000 mL as the reference standard, we evaluated the diagnostic accuracy of ICD-10 codes for PPH by estimating sensitivity, specificity, positive predictive value and negative predictive value with exact binomial 95% confidence intervals (CIs). In our secondary analysis, we assessed the ICD-10 coding accuracy for severe PPH, defined as an estimated blood loss >1000 mL and transfusion of at least 1 unit of red blood cells registered in the Scandinavian Donations and Transfusion database., Results: Of the 609 807 deliveries, 43 312 (7.1%) had an ICD-10 code for PPH and 45 071 (7.4%) had an estimated blood loss >1000 mL. The ICD codes had a sensitivity of 88.5% (95% CI 88.2-88.7), specificity of 99.4% (95% CI 99.4-99.4), positive predictive value of 92.0% (95% CI 91.8-92.3) and negative predictive value of 99.1% (95% CI 99.1-99.1). In our secondary analysis, on deliveries with severe PPH, the sensitivity for an ICD code was 91.3% (95% CI 90.7-91.9), whereas specificity was 83.5% (95% CI 82.3-84.6)., Conclusions: Our findings indicate that ICD-10 codes for PPH in Sweden have moderately high sensitivity and excellent specificity. These results suggest that PPH diagnostic codes in medical records and linked pregnancy and birth registers can be used for research, quality improvement and reporting PPH prevalence in Sweden., (© 2020 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Objectives: We assessed the incidence, risk factors and adverse birth outcomes associated with elevated liver enzymes and low platelets (HELLP) syndrome., Design: A retrospective population-based cohort study., Setting: Canada (excluding Quebec), 2012/2013-2015/2016., Population: Mothers with a singleton hospital live birth or stillbirth at ≥24 weeks' gestation (n = 1 078 323)., Methods: HELLP syndrome was identified using ICD-10-CA diagnostic code from delivery hospitalisation data. We used logistic regression to identify independent risk factors for HELLP syndrome by obtaining adjusted odds ratios (AOR) and 95% confidence intervals (CI), and to assess the associations with adverse outcomes., Main Outcome Measures: Adverse maternal (e.g. eclampsia) and fetal/neonatal outcomes (e.g. intraventricular haemorrhage, perinatal death)., Results: The incidence of HELLP syndrome was 2.5 per 1000 singleton deliveries (n = 2663). Risk factors included: age ≥35 years, rural residence, nulliparity, parity ≥4, pre-pregnancy and gestational hypertension and diabetes, assisted reproduction, chronic cardiac conditions, systemic lupus erythematosus, obesity, chronic hepatic conditions, placental disorders (e.g. fetomaternal transfusion) and congenital anomalies. PROM and age <25 years were inversely associated with HELLP syndrome (P-values <0.05). Women with the syndrome had a 10-fold higher maternal mortality (95% CI 1.6-84.3) and elevated severe maternal morbidity (9.6 versus 121.7 per 1000; AOR 12.5, 95% CI 11.1-14.1); and higher perinatal mortality (4.3 versus 21.0 per 1000; AOR 4.5, 95% CI 3.5-5.9) and perinatal mortality/severe neonatal morbidity (21.2 versus 202.4 per 1000; AOR 10.7, 95% CI 9.7-11.8)., Conclusion: HELLP syndrome is associated with specific pre-pregnancy and pregnancy risk factors, higher rates of maternal death, and substantially higher severe maternal morbidity, perinatal mortality and severe neonatal morbidity., Tweetable Abstract: HELLP syndrome is associated with higher maternal death rate, and substantially higher severe maternal and neonatal morbidity, and perinatal mortality., (© 2020 Royal College of Obstetricians and Gynaecologists.)

Background: Maternal overweight and obesity might increase risks of adiposity and cardiovascular and metabolic diseases in offspring. We examined associations between maternal overweight and obesity severity and risk of cardiovascular diseases in young offspring., Methods: In this population-based cohort study, we used data from live singleton births recorded in the Swedish Medical Birth Register. We calculated maternal BMI in early pregnancy from self-reported height and weight measurements at the first prenatal visit. We used multivariable Cox proportional hazards regression to estimate adjusted hazard ratios (HRs) and 95% CIs. We calculated the proportion of the associations mediated through known consequences of obesity that also predicted cardiovascular diseases and did family case-control analyses., Findings: We identified 2 230 115 live singleton infants (without congenital malformations) in Sweden registered between Jan 1, 1992, and Dec 31, 2016. Overall, 1741 (0·08%) offspring were diagnosed with a cardiovascular disease between ages 1 and 25 years. Cardiovascular disease rates by maternal BMI categories were 0·57 per 10 000 child-years (BMI 18·5-24·9 kg/m 2 ; normal weight), 0·61 per 10 000 child-years (25·0-29·9 kg/m 2 ; overweight), 0·67 per 10 000 child-years (30·0-34·9 kg/m 2 ; obesity grade I), 1·02 per 10 000 child-years (35·0-39·9 kg/m 2 ; obesity grade II), and 1·38 per 10 000 child-years (≥40·0 kg/m 2 ; obesity grade III). Compared with offspring of mothers with normal BMI, HRs of cardiovascular diseases were 1·10 (95% CI 0·97-1·25) for overweight, 1·16 (0·95-1·43) for obesity grade I, 1·84 (1·36-2·49) for obesity grade II, and 2·51 (1·60-3·92) for obesity grade III. Risks of cerebrovascular diseases increased with maternal obesity severity and were partly mediated through asphyxia-related neonatal complications. The sibling-cohort analysis also indicated a positive trend between maternal BMI and cardiovascular disease rates., Interpretations: Our findings indicate that maternal obesity might be a risk factor for cardiovascular diseases in childhood and early adulthood. These results need to be replicated and possible underlying mechanisms identified., Funding: Swedish Research Council for Health, Working Life and Welfare., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives: We sought to examine temporal trends in pelvic organ prolapse (POP) surgery in Canada., Methods: In this observational cross-sectional study, we used diagnostic and procedure codes from all hospitalizations and outpatient clinic visits in Canada (excluding Québec) from 2004 to 2014 to identify and analyze data on POP surgery., Results: There were 204 301 POP surgery visits from 2004 to 2014, and the rate of POP surgery declined from 19.3 to 16.0 per 10 000 women during this period. The rates of "native tissue reconstructive repair" and "hysterectomy without other procedure" declined from 15.0 to 12.8 per 10 000 women and 2.6 to 1.6 per 10 000 women, respectively. The rate of obliteration increased from 0.1 to 0.3 per 10 000 women (all P values for trend <0.01). Mesh procedures increased from 1.6 per 10 000 women in 2004 to 2.4 per 10 000 women in 2007 and 2008, and then declined to 1.3 per 10 000 women in 2014. Reconstructive mesh surgery using an abdominal open approach declined, while laparoscopic procedures increased over the period examined., Conclusion: The rates of POP surgery declined in Canada between 2004 and 2014. An increase was observed in obliteration procedures and in laparoscopic vaginal suspension and fixation with mesh., (Copyright © 2020 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.)

Objective: Clinician-initiated deliveries at 34 to 36 weeks gestation have increased in Canada since 2006, but the impacts of clinician-initiated deliveries on the overall preterm birth (PTB) rate and concomitant changes in neonatal outcomes are unknown. This study examined gestational age-specific trends in spontaneous and clinician-initiated PTB and associated neonatal mortality and morbidity., Methods: This population-based study included 1 880 444 singleton live births in Canada (excluding Québec) in 2009-2016, using hospitalization data from the Canadian Institute for Health Information. The primary outcomes were neonatal mortality and a composite outcome mortality and/or severe neonatal morbidity identified by International Statistical Classification of Diseases and Related Health Problems, 10th revision, Canada codes. Outcomes were stratified by spontaneous and clinician-initiated deliveries and gestational age categories. Logistic regression yielded adjusted odds ratios (aORs) per 1-year change and 95% confidence intervals (CIs) (Canadian Task Force Classification II-2)., Results: The PTB rate remained stable (6.2%) and the proportion of clinician-initiated PTBs increased from 31.0% to 37.9% (P < 0.001). Although overall neonatal mortality remained stable (1.1%), mortality declined among infants born spontaneously at 28 to 33 weeks gestation (aOR 0.92; 95% CI 0.87-0.97). The composite mortality and/or severe morbidity declined from 12.7% to 12.2% (aOR 0.98; 95% CI 0.97-0.99). Declines were observed in the rates of sepsis (aOR 0.96; 95% CI 0.95-0.98) and respiratory distress syndrome requiring ventilation (aOR 0.97; 95% CI 0.96-0.98), whereas rates of intraventricular hemorrhage increased (aOR 1.03; 95% CI 1.01-1.05)., Conclusion: With the increase in clinician-initiated deliveries, the stable rates of PTB and neonatal mortality and the decline in composite mortality and/or severe morbidity are encouraging findings. This study adds to clinical understanding of carefully timed and medically justified early interventions., (Copyright © 2019 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.)