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IntroductionSevere maternal morbidity (SMM)—an unexpected pregnancy-associated maternal outcome resulting in severe illness, prolonged hospitalisation or long-term disability—is recognised by many, as the preferred indicator of the quality of maternity care, especially in high-income countries. Obtaining comprehensive details on events and circumstances leading to SMM, obtained through maternity units, could complement data from large epidemiological studies and enable targeted interventions to improve maternal health. The aim of this study is to assess the feasibility of gathering such data from maternity units across Canadian provinces and territories, with the goal of establishing a national obstetric survey system for SMM in Canada.Methods and analysisWe propose a sequential explanatory mixed-methods study. We will first distribute a cross-sectional survey to leads of all maternity units across Canada to gather information on (1) Whether the unit has a system for reviewing SMM and the nature and format of this system, (2) Willingness to share anonymised data on SMM by direct entry using a web-based platform and (3) Respondents’ perception on the definition and leading causes of SMM at a local level. This will be followed by semistructured interviews with respondent groups defined a priori, to identify barriers and facilitators for data sharing. We will perform an integrated analysis to determine feasibility outcomes, a narrative description of barriers and facilitators for data-sharing and resource implications for data acquisition on an annual basis, and variations in top-5 causes of SMM.Ethics and disseminationThe study has been approved by the Mount Sinai and Hamilton Integrated Research Ethics Boards. The study findings will be presented at annual scientific meetings of the Society of Obstetricians and Gynaecologists of Canada, North American Society of Obstetric Medicine, and International Network of Obstetric Survey Systems and published in an open-access peer-reviewed Obstetrics and Gynaecology or General Internal Medicine journal.

Medically-indicated deliveries are common in twin pregnancies given the increased risk of various obstetric complications in twin compared to singleton pregnancies, mainly hypertensive disorders of pregnancy and foetal growth restriction. Due to the unique characteristics of twin pregnancies, the success rates and safety of labour induction may be different than in singleton pregnancies. However, while there are abundant data regarding induction of labour in singleton pregnancies, the efficacy and safety of labour induction in twin pregnancies have been far less studied. In the current manuscript we summarize available data on various aspects of labour induction in twin pregnancies including incidence, success rate, prognostic factors, safety and methods for labour induction in twins. This information may assist healthcare providers in counselling patients with twin pregnancies when labour induction is indicated.

Objective To evaluate whether pregnancy outcomes associated with hypertensive disorders of pregnancy in twin pregnancies differ relatively from those in singleton pregnancy. Methods We conducted a retrospective, population-based cohort study of all women with a liveborn singleton or twin hospital birth in Ontario, Canada, between 2012 and 2019. Data were obtained from the Better Outcomes Registry & Network Ontario. Pregnancy outcomes were compared between women with and without hypertensive disorders of pregnancy in twin gestations, and separately in singleton gestations. Adjusted relative risks (aRRs) and 95% CIs were generated using modified Poisson regression and were compared between twins and singletons using relative risk ratios. Results Overall, 932,218 women met the study criteria, of whom 917,542 (98.4%) and 14,676 (1.6%) had singleton and twin gestations, respectively. The incidence of hypertensive disorders of pregnancy was higher in women with twin compared with singleton gestations (14.4% vs 6.4%, aRR 1.85 [1.76-1.94]). Hypertensive disorders of pregnancy were associated with certain adverse outcomes in singleton gestations only and with other adverse outcomes in both the singleton and twin gestations, but the aRR was lower in twins. For example, preterm birth before 37 weeks of gestation (singletons: 15.2% [hypertensive disorders of pregnancy] vs 5.4% [no hypertensive disorders of pregnancy], aRR 2.42; twins: 67.5% [hypertensive disorders of pregnancy] vs 50.4% [no hypertensive disorders of pregnancy], aRR 1.30) and neonatal respiratory morbidity (singletons: 16.3% [hypertensive disorders of pregnancy] vs 8.7% [no hypertensive disorders of pregnancy], aRR 1.50; twins: 39.8% [hypertensive disorders of pregnancy] vs 32.7% [no hypertensive disorders of pregnancy], aRR 1.13). These findings persisted in the subgroups of women with preeclampsia and early-onset preeclampsia. Conclusions Although the absolute risk of adverse maternal and neonatal outcomes is higher in twin compared with singleton pregnancies, the incremental risk of adverse outcomes associated with hypertensive disorders in twin pregnancies is lower than the incremental risk in singleton pregnancies. These findings may be attributed in part to the higher baseline risk of preterm birth and adverse maternal and perinatal outcomes in twin compared with singleton pregnancies.

INTRODUCTION Since 2013, various guidelines for hypertension in pregnancy have been refined, no longer requiring proteinuria as a requisite criterion for preeclampsia. We aimed to evaluate the impact of the new definition on preterm birth (PTB) and adverse pregnancy outcomes. MATERIAL AND METHODS Women delivering in Ontario between April 2012 and November 2016 were included. Delivery

To investigate the current practices of maternal-fetal medicine (MFM) specialists regarding the prevention and management of preterm birth (PTB) in twin pregnancies.This was a cross-sectional study of Canadian MFM specialists. Participants responded to an anonymous survey regarding the prevention and management of PTB in twins, including lifestyle and gestational weight gain recommendations, cervical length screening, PTB prevention, and labour and delivery practices.Of 137 MFM specialists surveyed, 95 (69%) responded. Most MFM specialists recommend against activity restriction (77.9%), avoidance of sexual activity (96.7%), routine progesterone (97.8%), routine prophylactic cerclage (98.9%), and routine administration of antenatal corticosteroids (95.6%). There were considerable inconsistencies with respect to gestational weight gain management. Despite lack of support by guidelines, most MFM specialists reported using routine cervical length screening (97.8%) and progesterone for short cervix (92.3%). Over half (52.7%) of MFM specialists recommend cervical cerclage when the cervix is15mm. In cases of PTB, most MFM specialists recommend vaginal delivery when twins are in vertex presentation (63%-75%). MFM specialists are less likely to recommend vaginal delivery when twin B is non-vertex (35%-41%).There is a considerable variation among MFM specialists regarding the prevention and management of PTB in twins, and the practice of many MFM specialists differs from that recommended by professional societies' guidelines. These findings underscore the necessity for high-quality studies and up-to-date recommendations.

OBJECTIVE We aimed to quantify the risk of future maternal type 2 diabetes mellitus (T2DM) in women with gestational diabetes mellitus (GDM) based on the type and number of abnormal 75-g oral glucose tolerance test (OGTT) values and the diagnostic criteria used for the diagnosis of GDM. RESEARCH DESIGN AND METHODS We conducted a population-based retrospective cohort study of all nulliparous women with a live singleton birth who underwent testing for GDM using a 75-g OGTT in Ontario, Canada (2007–2017). We estimated the incidence rate (per 1,000 person-years), overall risk (expressed as adjusted hazard ratio [aHR]), and risk at 5 years after the index pregnancy of future maternal T2DM. Estimates were stratified by the type and number of abnormal OGTT values, as well as by the diagnostic criteria for GDM (Diabetes Canada [DC] vs. International Association of the Diabetes and Pregnancy Study Groups [IADPSG] criteria). RESULTS A total of 55,361 women met the study criteria. The median duration of follow-up was 4.4 (interquartile range 2.8–6.3; maximum 10.3) years. Using women without GDM as reference (incidence rate 2.18 per 1,000 person-years), women with GDM were at an increased risk of future T2DM; this risk was greater when using the DC compared with the IADPSG criteria (incidence rate 18.74 [95% CI 17.58–19.90] vs. 14.07 [95% CI 13.24–14.91] per 1,000 person-years, respectively). The risk of future maternal T2DM increased with the number of abnormal OGTT values and was highest for women with three abnormal values (incidence rate 49.93 per 1,000 person-years; aHR 24.57 [95% CI 21.26–28.39]). The risk of future T2DM was also affected by the type of OGTT abnormality: women with an abnormal fasting value had the greatest risk, whereas women with an abnormal 2-h value had the lowest risk (aHR 14.09 [95% CI 12.46–15.93] vs. 9.22 [95% CI 8.19–10.37], respectively). Similar findings to those described above were observed when the risk of T2DM at a fixed time point of 5 years after the index pregnancy was considered as the outcome of interest. CONCLUSIONS In women with GDM, individualized information regarding the future risk of T2DM can be provided based on the type and number of abnormal OGTT values, as well as the diagnostic criteria used for the diagnosis of GDM.

To determine the feasibility of rescue cerclage and amnioreduction at advanced cervical dilation or gestational age.We present a retrospective case series of women who underwent rescue cerclage at either an advanced gestational age (24 + 0 to 24 + 6 weeks) or cervical dilation (≥4 cm), with a subset undergoing amnioreduction prior to cerclage placement.Nine women were included and amnioreduction was performed in 7 (78%). A bi-modal distribution of obstetric outcomes was observed, with 5 (56%) women delivering ≥34 weeks gestation, 3 (33%) of which delivered at term. Two (22%) women experienced intra-operative rupture of membranes and subsequent perinatal deaths. Two (22%) women delivered extremely premature, with one resulting in infant death.Our data show that rescue cerclage with amnioreduction may be successful at advanced gestational ages or cervical dilations, suggesting that these women should be included in prospective studies to better establish the efficacy and safety of this procedure.

Objective: The aim of the current study was to identify the optimal cutoff that should define discordance in dichorionic twin gestations through correlation with abnormal placental pathology as a specific measure of fetal growth restriction of the smaller twin. Methods: We performed a retrospective cohort study of all women with dichorionic twin pregnancies who gave birth in a single center between 2002 and 2015. We investigated the association between the level of growth discordance and maternal vascular malperfusion (MVM) pathology in the placenta of the smaller twin, with and without adjustment for whether the smaller twin is small for gestational age (SGA). Results: A total of 1,198 women with dichorionic twin gestation met the study criteria. The rate of MVM pathology in the placenta of the smaller twin increased with the level of discordance and was most obvious for discordance ≥25% (rate of MVM 12.0% compared with 2.8% in cases with discordance Conclusion: Our findings suggest that discordant growth in dichorionic twins should raise the concern of fetal growth restriction of the smaller twin, irrespective of whether the smaller twin is SGA, only when the discordance s ≥25%. The association of lower levels of discordance with abnormal placental pathology is mainly driven by the confounding effect of SGA of the smaller twin.

To evaluate the effect of the choice growth chart and threshold used to define small for gestational age (SGA) on the predictive value of SGA for placenta-related or unexplained antepartum stillbirth.A retrospective cohort study of all women with a singleton pregnancy who gave birth 24 week gestation in a single center (2000-2016). The exposure of interest was SGA, defined as birth weight 10th or 25th centile according to three fetal growth charts (Hadlock et al., Radiology 181:129-133, 1991; intergrowth-21st (IG21), WHO 2017, and a Canadian birthweight-based reference-Kramer et al., Pediatrics 108:E35, 2001). The outcome of interest was antepartum stillbirth due to placental dysfunction or unknown etiology. Cases of stillbirth attributed to other specific etiologies were excluded.A total of 49,458 women were included in the cohort. There were 103 (0.21%) cases of stillbirth due to placental dysfunction or unknown etiology. For cases in the early stillbirth cluster (≤ 30 weeks), the detection rate was high and was similar for the three ultrasound-based fetal growth charts of Hadlock, IG21, and WHO (range 83.3-87.0%). In contrast, the detection rate of SGA for cases in the late stillbirth cluster ( 30 weeks) was low, being highest for WHO and Hadlock (36.7% and 34.7%, respectively), and lowest for IG21 (18.4%). Using a threshold of the 25th centile increased the detection rate for stillbirth by approximately 15-20% compared with that achieved by the 10th centile cutoff.At 30 week gestation, the Hadlock or WHO fetal growth charts provided the best balance between detection rate and false positive rate for stillbirth.

To compare pregnancy outcomes in women with pPROM and a cervical cerclage in whom the cerclage was removed within 24 h and those in whom the cerclage was retained in situ. A two-center retrospective cohort study of women with a singleton gestation with pPROM at 48 h (87.2% vs. 65.2%, p = 0.03; aOR 3.9, 95% CI 3.1–4.9) or > 7 days (29.8% vs. 8.7%, p = 0.04; aOR 7.0, 95% CI 2.5–19.6) compared with women in whom cerclage was removed. Furthermore, chorioamnionitis rate was lower in the cerclage retention group compared to cerclage removal group (aOR 0.7, 95% CI 0.5–1.0). There were no differences between the groups in early neonatal sepsis, severe brain injury, or composite neonatal outcome. In women with pPROM and cervical cerclage, retention of cerclage may be associated with a longer latency period, and a lower chorioamnionitis rate, without an associated increase in the risk of neonatal infectious morbidity. Presentation information: The abstract of this study was presented as a poster at the 38th SMFM (Society of Maternal and Fetal Medicine) annual meeting, February 2018, Dallas, Texas, USA.

Objectives To evaluate the utility of ultrasound markers in the management of pregnancies complicated by preterm prelabor rupture of membranes (PPROM) between 23 + 0 and 33 + 6 weeks' gestation, and to assess the ability of ultrasound markers to predict adverse neonatal outcomes. Methods This was a retrospective cohort study of all patients with PPROM between 23 + 0 and 33 + 6 weeks' gestation and latency period (PPROM to delivery) > 48 h, who delivered before 34 weeks' gestation at a tertiary referral center between 2005 and 2017. All patients underwent a non-stress test daily and an ultrasound scan twice a week for assessment of amniotic fluid volume, biophysical profile (BPP) and umbilical artery (UA) pulsatility index (PI). In patients with suspected fetal growth restriction, fetal middle cerebral artery (MCA)-PI was also assessed and the cerebroplacental ratio (CPR) calculated. The last ultrasound examination performed prior to delivery was analyzed. We compared the characteristics and outcomes between women who were delivered owing to clinical suspicion of chorioamnionitis and those who were not delivered for this indication. The primary objective was to evaluate the utility of ultrasound in the management of patients with PPROM. The secondary objective was to assess the diagnostic performance of ultrasound markers (BPP score 95th percentile, MCA-PI Results A total of 504 women were included in the study, comprising 120 with suspected chorioamnionitis and 384 without. Women with suspected chorioamnionitis, compared with those without, were less likely to be nulliparous (34.2% vs 45.3%; P = 0.03) and more likely to have fever (50.8% vs 2.6%; P 95th percentile was similar between the two groups. There was a higher incidence of composite adverse neonatal outcome in the group with suspected chorioamnionitis than in the group without (78.3% vs 64.3%, respectively; P = 0.004). However, on logistic regression analysis, none of the ultrasound markers evaluated was found to be associated with chorioamnionitis or composite adverse neonatal outcome, and they all had a poor diagnostic performance for the prediction of chorioamnionitis and composite adverse neonatal outcome. Conclusions Commonly used ultrasound markers in pregnancies complicated by PPROM were similar between women delivered for suspected chorioamnionitis and those delivered for other indications, and performed poorly in predicting composite adverse neonatal outcome. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

To determine the rate of sonographic placental markers and their predictive value for preeclampsia and fetal growth restriction in women with chronic kidney disease (CKD).A retrospective cohort study of women with CKD followed at a tertiary referral center between 2016 and 2019 (n = 86). All women underwent 2nd trimester sonographic placental examinations that included assessment of placental morphology, umbilical cord, and uterine artery Doppler. Continuous placental markers were converted to multiples on medians (MoM).Predictive value of sonographic markers for preeclampsia and birthweight 10th percentile.Women in the cohort had a high rate of preeclampsia (24.4%), birthweight 10th% (26.7%), and preterm birth (30.2%). The most important markers were placental volume and uterine artery Doppler: the risk of preeclampsia was elevated in women with low placental volume (51.7% vs. 10.9%; OR = 8.79 [2.70-28.59] for preeclampsia; and 40.0% vs. 9.1%; OR = 6.67 [1.85-24.04] for preterm preeclampsia), and in women with bilateral uterine artery notching (62.5% vs. 20.8%; OR = 6.35 [1.37-29.45] for preeclampsia; and 62.5% vs. 10.4%; OR = 14.38 [1.29-71.75] for preterm preeclampsia). The combination of both markers had the strongest predictive value for preeclampsia (positive likelihood ratio = 8.25 [6.84-9.95]). Low placental volume and bilateral uterine notching were also associated with birthweight 10th percentile.A 2nd-trimester sonographic placental study can identify a subgroup of women with CKD who are at most risk of preeclampsia and fetal growth restriction. Such data may inform their subsequent perinatal care and assist care providers in the often challenging distinction between preeclampsia flare of underlying CKD.

We retrospectively included women with abnormal FTS analytes and compared outcomes between those with elevated and normal UtA-PI. Out of 582 women with abnormal FTS analytes, 65 (11.2%) had elevated UtA-PI. Neonates of women in this group had higher rates of birth weight3rd, 5th, and 10th percentile. The area under the ROC curve for predicting FGR10th percentile by UtA-PI was 0.584, for FGR5th percentile 0.593, and for FGR3rd percentile 0.720. In women with abnormal FTS, elevated UtA-PI is associated with higher rates of FGR, but its predictability is moderate-to-poor.

Background Skin-to-skin contact between mother and infant immediately after birth is recommended regardless of delivery method; however, it is less common after cesarean delivery. We aimed to describe and compare women's experiences of cesarean birth with and without skin-to-skin contact at an urban tertiary care hospital. Methods In this hermeneutic phenomenologic study, we used semistructured telephone interviews from 2015 to 2018 to interview a convenience sample of women who delivered at term by scheduled skin-to-skin cesarean birth at an urban tertiary care hospital in Toronto, Ontario. Women were invited to participate if they had had a previous planned or unplanned cesarean birth and a scheduled skin-to-skin cesarean birth between 2013 and 2017. Participants were excluded if they had antenatally diagnosed conditions, they delivered before 37 weeks, they had general anesthesia, their condition was unstable at the time of surgery, a skin-to-skin cesarean birth was not possible or they declined skin-to-skin cesarean birth. Interviews were recorded, transcribed and analyzed by means of thematic analysis. Results Ten women were interviewed 1-19 months postpartum. Four central themes emerged: support for skin-to-skin cesarean birth (women feeling supported by their families and health care providers); control (participants experiencing greater control during their skin-to-skin cesarean birth); connection with the infant, which enabled women to be active participants in their delivery, enhanced bonding and intimacy, facilitated breastfeeding and bolstered confidence during early parenthood; and logistic considerations, with participants recognizing that skin-to-skin cesarean birth required additional resources. Interpretation These findings refine what is known about skin-to-skin cesarean birth and provide a critical perspective, that of mothers. They support the transformation of traditional operating room dynamics to a more patient-centred environment.

The screening accuracy of the 50 g-glucose challenge test (50 g-GCT) for gestational diabetes (GDM) has been described in singleton pregnancies. Given the physiologic differences and greater increase in insulin resistance in twin compared with singleton pregnancies, the performance of the 50 g-GCT in twin pregnancies may differ.To perform a systematic review on the screening performance of the 50 g-GCT for gestational diabetes in twin pregnancies.Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL).We included randomized controlled trials or cohort studies that evaluated the screening accuracy of the 50 g-GCT for GDM in twin pregnancies using the two-step approach. The primary outcome was the positive predictive value of the 50 g-GCT for GDM using the 140 mg/dL (7.8 mmol/L) threshold.Methodological quality of included studies was assessed using the QUADAS-2 tool. The positive predictive value (PPV) was pooled for studies that used similar test characteristics.From 2044 citations, 7 retrospective cohort studies with a total of 55,597 participants were included (6.5% twins and 93.5% singletons). The majority of studies evaluated a 50-g GCT cutoff point of 140 mg/dL. The pooled PPV for a threshold of 140 mg/dL (7.8 mmol/L) for twins was 22.58% (95% CI: 0.1912-0.2647,The PPV of 50 g-GCT for GDM in twin pregnancies when using a threshold of 140 mg/dL (7.8 mmol/L) is approximately 23%. There is currently no data on the sensitivity and specificity of the 50 g-GCT in twins.

Background: People whose singleton pregnancy is affected by hypertensive disorders of pregnancy (HDP) are at risk of future cardiovascular disease. It is unclear, however, whether this association can be extrapolated to twin pregnancies. We aimed to compare the association between HDP and future cardiovascular disease after twin and singleton pregnancies. Methods: We conducted a population-based retrospective cohort study that included nulliparous people in Ontario, Canada, 1992–2017. We compared the future risk of cardiovascular disease among pregnant people from the following 4 groups: those who delivered a singleton without HDP (referent) and with HDP, and those who delivered twins either with or without HDP. Results: The populations of the 4 groups were as follows: 1 431 651 pregnant people in the singleton birth without HDP group; 98 631 singleton birth with HDP; 21 046 twin birth without HDP; and 4283 twin birth with HDP. The median duration of follow-up was 13 (interquartile range 7–20) years. The incidence rate of cardiovascular disease was lowest among those with a singleton or twin birth without HDP (0.72 and 0.74 per 1000 person-years, respectively). Compared with people with a singleton birth without HDP, the risk of cardiovascular disease was highest among those with a singleton birth and HDP (1.47 per 1000 person-years; adjusted hazard ratio [HR] 1.81 [95% confidence interval (CI) 1.72–1.90]), followed by people with a twin pregnancy and HDP (1.07 per 1000 person-years; adjusted HR 1.36 [95% CI 1.04–1.77]). The risk of the primary outcome after a twin pregnancy with HDP was lower than that after a singleton pregnancy with HDP (adjusted HR 0.74 [95% CI 0.57–0.97]), when compared directly. Interpretation: In a twin pregnancy, HDP are weaker risk factors for postpartum cardiovascular disease than in a singleton pregnancy.

Lateral placentation may compromise placental perfusion, and we aimed to assess whether it impacts pregnancy outcomes. This single-center retrospective study included 1203 singleton pregnancies, categorized into two groups according to placental location. Women with lateral placenta had significantly higher risk of preterm birth

A structured approach to hemorrhagic emergencies in obstetrics has gained popularity with the implementation of massive hemorrhage protocols. The trauma literature suggests that routine quality reviews should be in place to improve patient outcomes. The aim of this study was to develop quality indicators and assess compliance by the clinical team.A multidisciplinary team set the institutional quality indicators for the massive hemorrhage protocol review. A retrospective review of all obstetrical massive hemorrhage protocol activation events from September 2010 to January 2015 was performed. All protocol events occurred before the creation of the quality indicators. Data were retrieved from patient records.There were 17 (0.09%) protocol activations for 19 790 deliveries during the study period. All 17 (100%) patients received at least one unit of red blood cells. Overactivation, defined as the transfusion of2 units of red blood cells, occurred in two cases (12%). Common causes of non-compliance were: 24% (4/17) temperature monitoring, 18% (3/17) lactate measurement, 41% (7/17) arterial blood gas sampling, and 18% (3/17) hemoglobin maintenance within the target range of 55-95 g/L. Admission to intensive care and peripartum hysterectomy occurred in 12 and 5 cases (71% and 29%), respectively.Suboptimal compliance was found in multiple areas, which may be attributable to the low frequency of activation of our massive haemorrhage protocol in obstetrics. The quality targets identified in this report can act as a basis for other institutions developing quality indicators to evaluate performance.

Objective: To determine whether preterm birth in a twin pregnancy increases the risk of subsequent preterm birth (PTB) in a singleton pregnancy and to identify predictors for singleton PTB in women with previous twin PTB.Method: A retrospective cohort study of women with prior twin birth followed by a singleton birth in two tertiary referral centres between 2000 and 2016 was conducted. Rate of PTB in subsequent singleton pregnancy was compared between women who experienced previous preterm versus term twin birth. Analysis was further stratified by gestational age at twin and singleton birth, etiology for PTB and chorionicity in the twin pregnancy.Results: A total of 378 women met the inclusion criteria, of whom 252 (66.7%) experienced PTB in the index twin pregnancy. The overall rate of PTB in the subsequent singleton pregnancy was 11.6% (44/378). Women with prior twin PTB had a higher rate of PTB in the subsequent singleton pregnancy compared with women with prior term twin birth (17.5 versus 6.3%, p = .003, or 3.12, 95%-CI 1.42-6.85), mainly due to a higher rate of late singleton preterm birth (13.1 versus 4.0%, p = .005). Findings of higher odds of PTB in the subsequent singleton pregnancy was limited to women who gave birth before 340/7 weeks in the twin pregnancy and was related to the degree of prematurity (prior twin PTB at 300/7-336/7 weeks: OR 3.09, 95%-CI 1.12-8.51; prior twin PTB at

Background The primary aim of this study was to examine weight gain during pregnancy and associated adverse outcomes across different types of antenatal health care providers. Our research question examined whether type of antenatal health care provider (family physician, obstetrician, midwife, or family physician plus obstetrician) was associated with differing rates of excess or inadequate weight gain and associated adverse outcomes including being large for gestational age, being small for gestational age, cesarean delivery and preterm birth. Methods This retrospective cohort study used data from the Better Outcomes Registry & Network Information System, 2014-2016, for singleton hospital births at 20-42 weeks' gestation in Ontario. We calculated descriptive statistics to summarize patient characteristics and outcomes by antenatal health care provider. We calculated crude and adjusted relative risks with 95% confidence intervals (CIs) for the exposure (weight gain during pregnancy) relative to each secondary outcome by health care provider. We calculated population attributable fractions with 95% CIs to assess the proportion of secondary outcomes that could be prevented if inadequate or excess weight gain (according to the 2009 Institute of Medicine guidelines) were removed by health care provider. Results The final cohort consisted of 231 697 pregnancies, of which 26 043 (11.2%), 136 994 (59.1%), 32 262 (13.9%) and 36 298 (15.7%) were managed by a family physician, obstetrician, midwife, and family physician plus obstetrician, respectively. Rates of weight gain below, within or above recommended levels were 31 742 (13.7%), 71 826 (31.0%) and 128 128 (55.3%), respectively, and did not differ across health care provider groups. No difference was observed in rates of secondary outcomes according to weight gain across health care providers. Excess weight gain was associated with a significant risk of being large for gestational age and cesarean delivery, and inadequate weight gain was associated with an increased risk of being small for gestational age and preterm birth. The population attributable fractions indicated a pronounced contribution of excess weight gain to being large for gestational age across all health care provider groups. Interpretation Weight gain during pregnancy and rates of associated secondary outcomes did not differ according to antenatal health care provider. This suggests a need for further research exploring counselling techniques and strategies for all types of antenatal health care providers to use in order to promote optimal weight gain during pregnancy.

Data on the optimal gestational weight gain in twin pregnancies are limited. As a result, the Institute of Medicine currently provides only provisional recommendations on gestational weight gain in this population.This study aimed to identify the optimal range of gestational weight gain in twin pregnancies and to estimate the association between inappropriate gestational weight gain and adverse pregnancy outcomes.This was a retrospective cohort study of all women with twin pregnancies that were followed up in a single, tertiary center between 2000 and 2014. We used 2 approaches to identify the optimal range of gestational weight gain: a statistical approach (the interquartile range of gestational weight gain in low-risk pregnancies with normal outcomes) and an outcome-based approach (by identifying thresholds of gestational weight gain below or above which the rate of adverse outcomes increases). The primary outcome was preterm birth. Associations of gestational weight gain below or above the normal range with the study outcomes were estimated using logistic regression analysis and were expressed as adjusted odds ratio with 95% confidence intervals. These associations were stratified by prepregnancy body mass index group.A total of 1274 women with twin pregnancies met the study criteria: 43 were classified as underweight, 777 were normal weight, 278 were overweight, and 176 were obese. Our estimates of the optimal gestational weight gain range were similar to those recommended by the Institute of Medicine except for the obese category, in which our optimal gestational weight gain range at 37 weeks (9.3-16.3 kg) was lower than in the provisional Institute of Medicine recommendations (11.3-19.1 kg). Nearly half of our cohort experienced inappropriate gestational weight gain: 30% (n=381) gained weight below and 17% (n=216) gained weight above current Institute of Medicine recommendations. In the normal weight group, gestational weight gain below recommendations was associated with an increased risk of preterm birth and birthweight at the10th centile and with a reduction in the risk of hypertensive disorders, whereas gestational weight gain above recommendations was associated with an increased risk of hypertensive disorders and a reduction in the risk of birthweight at the10th centile. Associations were less consistent in the overweight and obese groups.These findings identify gestational weight gain as a potentially modifiable risk factor for preterm birth and other pregnancy complications in twin gestations. Further prospective studies are needed to determine whether interventions aimed at optimizing gestational weight gain can improve the outcomes of these high-risk pregnancies.

Background Estimation of fetal weight (EFW) by ultrasound is useful in clinical decision-making. Numerous formulas for EFW have been published but have not been validated in pregnancies complicated by preterm premature rupture of membranes (PPROM). The purpose of this study is to compare the accuracy of EFW formulas in patients with PPROM, and to further evaluate the performance of the most commonly used formula - Hadlock IV. Methods A retrospective cohort study of women with singleton gestations and PPROM, admitted to a single tertiary center between 2005 and 2017 from 220/7–330/7 (n = 565). All women had an EFW within 14 days of delivery by standard biometry (biparietal diameter, head circumference, abdominal circumference and femur length). The accuracy of previously published 21 estimated EFW formulas was assessed by comparing the Pearson correlation with actual birth weight, and calculating the random error, systematic error, proportion of estimates within 10% of birth weight, and Euclidean distance. Results The mean gestational was 26.8 ± 2.4 weeks at admission, and 28.2 ± 2.6 weeks at delivery. Most formulas were strongly correlated with actual birth weight (r > 0.9 for 19/21 formulas). Mean systematic error was − 4.30% and mean random error was 14.5%. The highest performing formula, by the highest proportion of estimates and lowest Euclidean distance was Ott (1986), which uses abdominal and head circumferences, and femur length. However, there were minimal difference with all of the first 10 ranking formulas. The Pearson correlation coefficient for the Hadlock IV formula was strong at r = 0.935 (p p p Conclusions In women with singleton gestation and PPROM, the Ott (1986) formula for EFW was the most accurate, yet all of the top ten ranking formulas performed quite well. The commonly used Hadlock IV performed quite similarly to Ott’s formula, and is acceptable to use in this specific setting.

Background In the Twin Birth Study, women at 320/7–386/7 weeks of gestation, in whom the first twin was in cephalic presentation, were randomized to planned vaginal delivery or cesarean section. The study found no significant differences in neonatal or maternal outcomes in the two planned mode of delivery groups. We aimed to compare neonatal and maternal outcomes of twin gestations without spontaneous onset of labor, who underwent induction of labor or pre-labor cesarean section as the intervention of induction may affect outcomes. Methods In this secondary analysis of the Twin Birth Study we compared those who had an induction of labor with those who had a pre-labor cesarean section. The primary outcome was a composite of fetal or neonatal death or serious neonatal morbidity. Secondary outcome was a composite of maternal morbidity and mortality. Trial Registration: NCT00187369. Results Of the 2804 women included in the Twin Birth Study, a total of 1347 (48%) women required a delivery before a spontaneous onset of labor occurred: 568 (42%) in the planned vaginal delivery arm and 779 (58%) in the planned cesarean arm. Induction of labor was attempted in 409 (30%), and 938 (70%) had a pre-labor cesarean section. The rate of intrapartum cesarean section in the induction of labor group was 41.3%. The rate of the primary outcome was comparable between the pre-labor cesarean section group and induction of labor group (1.65% vs. 1.97%; p = 0.61; OR 0.83; 95% CI 0.43–1.62). The maternal composite outcome was found to be lower with pre-labor cesarean section compared to induction of labor (7.25% vs. 11.25%; p = 0.01; OR 0.61; 95% CI 0.41–0.91). Conclusion In women with twin gestation between 320/7–386/7 weeks of gestation, induction of labor and pre-labor cesarean section have similar neonatal outcomes. Pre-labor cesarean section is associated with favorable maternal outcomes which differs from the overall Twin Birth Study results. These data may be used to better counsel women with twin gestation who are faced with the decision of interventional delivery.

Objective: Ultrasound determination of chorionicity is poor in early pregnancy in China. In an effort to increase the accuracy rate of prompt chorionicity determination, clinical training was provided to primary care physicians. This study assesses the effects of implementing clinical guidelines on chorionicity determination. Methods: A multi‑centered cohort study was conducted between January 2014 and June 2017 in 12 hospitals without fetal medicine centers. In 2014, the obstetricians and ultrasound physicians were trained in clinical practice and ultrasound examination relating to chorionicity determination. Linear and binary regression analyses were conducted to identify the effects of introducing the new protocols, including the diagnosis rate of chorionicty and perinatal outcomes, taking the data from 2014 as a baseline. Pregnancy outcomes were additionally adjusted for maternal age. Results: During the period of this study, 3,599 twin pregnancies from 12 centers were enrolled, and a total of 2,998 twin pregnancies were extracted. The rate of overall chorionicity determination, including antenatal and postpartum diagnosis, increased successively from 49.5% in 2014 to 93.5% in 2017 (P < 0.0001). The rate of ultrasonic chorionicity diagnosis before 14 weeks increased from 25.2% in 2014 to 65.0% in 2017 (P < 0.0001). These changes were associated with decreasing incidence of preterm birth, a lower risk of stillbirth, whether for one (P = 0.0456 in 2016) or two fetuses (P = 0.0470 in 2016; P = 0.0042 in 2017) and a decreased rate of admission to neonatal intensive care unit (43.0% in 2014, 37.4% in 2017; P = 0.0032). Conclusions: The implementation of a clinical practice guideline improved both overall and early chorionicity determinations. Regular training workshops of antenatal care are recommended to further promote capability in clinical diagnosis and treatment.

Background Iron deficiency in pregnancy is associated with inferior maternal and fetal outcomes. Postpartum depression, prematurity, intrauterine growth restriction, impaired childhood cognition and transfusion are all sequelae of maternal iron deficiency anemia. Transfusion to women of childbearing age has important consequences including increasing the risk of hemolytic disease of the fetus and newborn with future pregnancies. The relative contribution of iron deficiency to transfusion rates in the peripartum period is unknown. This study aimed to identify the prevalence of iron deficiency and anemia in pregnant women that received peripartum transfusions relative to age-matched non-transfused controls. Methods We performed a retrospective case-control study of all women that were transfused in the peripartum period from January, 2014 to July, 2018. Cases were compared to the next age matched control to deliver at our institution. The primary objective was to determine the proportion of patients with iron deficiency in pregnancy or anemia in pregnancy in cases and controls. Charts were reviewed for predisposing risk factors for iron deficiency, laboratory measures of iron deficiency and anemia, iron supplementation history and maternal and fetal outcomes. Factors associated with peripartum transfusion were analyzed using a multivariate logistic regression. Results 169 of 18, 294 (0.9%) women were transfused in the peripartum period and 64 (44%) of those transfused received 1 unit. Iron deficiency or anemia were present in 103 (71%) transfused women and 74 (51%) control women in pregnancy (OR 2.34, 95% CI: 3.7–18.0). Multivariate analysis identified social work involvement (adjusted OR 4.1, 95% CI: 1.8–10.1), intravenous iron supplementation in pregnancy (adjusted OR 3.8, 95% CI: 1.2–17.4) and delivery by unscheduled cesarean section (adjusted OR 2.8, 95% CI: 1.3–6.2) as significant predictors of peripartum transfusion. Conclusions Pregnant women being followed by a social worker, receiving intravenous iron supplementation in pregnancy or who deliver by unscheduled cesarean section are more likely to receive a red blood cell transfusion. Women with iron deficiency or anemia in pregnancy are at increased risk of peripartum blood transfusions and warrant early and rigorous iron supplementation.

Background: Preterm birth (PTB) is a major cause of infant death globally. The rising rates of pre-pregnancy diabetes mellitus (D), obesity (O) and chronic hypertension (H) will place a significant burden on maternal-fetal health but their combined influence on PTB is unknown. Methods: Population-based cohort study, Ontario, Canada, April 1, 2012 to March 31 2016. Participants were 506,483 women with a singleton livebirth or stillbirth at > 20 weeks' gestation. The exposures of interest were D, O and H, individually, and in various combinations. The primary outcome was PTB at 241/7 to 366/7 weeks. PTB was further analyzed by spontaneous or provider-initiated, early (< 34 weeks) or late (34-37 weeks), and the co-presence of preeclampsia, large for gestational age (LGA), and small for gestational age (SGA) birthweight. Multivariable Poisson regression models with robust error variance were used to generate relative risks (RR), further adjusted for maternal age and parity (aRR). Population attributable fractions were then calculated for each of the outcomes by exposure state. Findings: Relative to women without D or O or H, the aRR for PTB were (3.09, 95% CI 2.80-3.40) with D + O, 6.34 (95% CI 5.15-7.81) with D + H, 2.96 (95% CI 2.70-3.24) with O + H, and 5.55 (95% CI 4.76-6.47) with D + O + H. In women with D + H, aRR was more pronounced for provider-initiated PTB (10.99, 95% CI 8.40-14.38) than for spontaneous PTB (3.05, 95% CI 1.92-4.85). Those with D + O + H had an aRR of 9.21 (95% CI 4.97-17.04) for PTB with an SGA newborn relative to those without D or O or H. Interpretation: Combinations of D, O and H significantly magnify the risk of PTB, especially provider-initiated PTB, and PTB with altered fetal growth or preeclampsia. These data may inform health policy and clinical decision-making both at the population and patient level. Funding: CIHR. Declaration of Interest: All authors report no conflict of interest Ethical Approval: Ethics approval was obtained from the St. Michael’s Hospital Research Ethics Board (REB # 16-345).

Background The rate of cesarean delivery is continuously increasing with the leading indication being a previous cesarean delivery. For women with 1 previous cesarean delivery, it is generally agreed that the optimal timing of delivery by elective cesarean delivery is during the 39th week of gestation, whereas for women with ≥2 previous cesarean deliveries, the optimal delivery time remains debatable. Objective To assess the maternal and neonatal risks associated with elective delivery at different gestational ages ranging from 37 0/7 to 39 6/7 weeks’ gestation and to compare it with expectant management among women with at least 2 previous cesarean deliveries. Study Design This was a retrospective, population-based cohort study of all women with at least 2 previous cesarean deliveries who delivered after 36 6/7 weeks of gestation in Ontario, Canada, between April 2012 and March 2019. Women with multifetal pregnancies or major fetal anomalies were excluded. For each completed gestational week, outcomes of women who had an elective repeat cesarean delivery at that week solely because of 2 previous cesarean deliveries were compared with the outcomes of those who were managed expectantly and delivered at a later gestational age. The primary outcome was a composite of maternal outcomes including mortality and severe maternal morbidity. Secondary outcomes were adverse neonatal outcomes. Results A total of 26,522 women met the inclusion criteria. The maternal risk was similar for elective delivery at 37 0/7 to 38 6/7 weeks of gestation compared with expectant management. However, elective delivery at 39 0/7 to 39 6/7 weeks’ gestation was associated with a decreased risk for adverse outcomes when compared with expectant management (adjusted risk ratio, 0.51; 95% confidence interval, 0.29–0.91). For the neonate, elective delivery during the 37th week of gestation significantly increased the incidence of the composite adverse outcome than in an ongoing pregnancy (adjusted risk ratio, 1.68; 95% confidence interval, 1.39–2.01), but was comparable for elective delivery at 38 0/7 to 39 6/7 weeks’ gestation and expectant management. The risk for an unplanned cesarean delivery increased from 6.5% before 38 weeks’ gestation to 21.7% before 39 weeks’ gestation and to 32.6% before 40 weeks’ gestation. Conclusion For women with ≥2 cesarean deliveries, elective delivery at 38 0/7 to 38 6/7 weeks’ gestation likely represents the optimal balance between neonatal and maternal risk while decreasing the likelihood of an unplanned cesarean delivery.

In singletons, the pathogenesis of hypertensive disorders of pregnancy (HDP) is attributed to abnormal placentation, characterized by maternal vascular malperfusion (MVM) lesions. Whether MVM plays a similar role in twin pregnancies is unclear. The purpose of the study was to compared placental pathology findings between dichorionic-twin and singleton pregnancies complicated by HDP.Retrospective cohort study of women with dichorionic-twin or singleton pregnancies complicated by HDP who gave birth in a single tertiary center between 2001 and 2015. Placental abnormalities were classified into lesions associated with MVM, fetal vascular malperfusion, placental hemorrhage and chronic villitis. Placental findings and neonatal outcomes were compared between twin and singleton pregnancies.A total of 144 women with twins and 768 women with a singleton pregnancy met the inclusion criteria. Compared with HDP singletons, twins with HDP had higher mean birth weights, were less likely to be small for gestational age and be born at34 and at32 weeks. Twins had lower odds for placental weight below10th percentile (aOR 0.49, 95%CI 0.33-0.71), for MVM pathology (aOR 0.28, 95%CI 0.20-0.39) and for fetal vascular malperfusion pathology (aOR 0.65, 95%CI 0.45-0.93). These finding remained significant in the subpopulation of early onset HDP (34 weeks) and small for gestational newborn.Our findings support the hypothesis that MVM are less relevant to the pathogenesis of HDP in twin pregnancies and suggest that other placental or non-placental factors are responsible for the increased risk of HDP in twin pregnancies.

To assess whether routine induction of labor at 38 or 39 weeks in women with chronic hypertension is associated with the risk of superimposed preeclampsia or cesarean delivery.We conducted a retrospective population-based study of women with chronic hypertension who had a singleton hospital birth at 38 0/7 weeks of gestation of gestation in Ontario, Canada, between 2012 and 2016. Women who underwent induction of labor at 38 0/7 to 38 6/7 weeks of gestation for chronic hypertension (n=281) were compared with those who were managed expectantly during that week and remained undelivered at 39 0/7 weeks of gestation (n=1,606). Separately, women who underwent induction of labor at 39 0/7 to 39 6/7 weeks of gestation for chronic hypertension (n=259) were compared with women who remained undelivered at 40 0/7 weeks of gestation (n=801).Of 534,529 women gave birth during the study period, 6,054 (1.1%) had chronic hypertension and 2,420 met the inclusion criteria. Women managed expectantly at 38 or 39 weeks of gestation were at risk of new-onset superimposed preeclampsia (19.2% [308/1,606] and 19.0% [152/801], respectively) and eclampsia (0.6% [10/1,606] and 0.7% [6/801], respectively), and more than half underwent induction of labor later in gestation (56.8% and 57.8%, respectively). The risk of cesarean delivery in the induction groups was lower (38 weeks of gestation) or similar (39 weeks of gestation) to that observed in women managed expectantly at the corresponding weeks (38 weeks of gestation: 17.1% vs 24.0%, adjusted relative risk 0.74 [95% CI 0.57-0.95]; 39 weeks of gestation: 20.1% vs 26.0%, adjusted relative risk 0.90 [95% CI 0.69-1.17]).Our findings suggest that in women with isolated chronic hypertension, induction of labor at 38 or 39 weeks of gestation may prevent severe hypertensive complications without increasing the risk of cesarean delivery.

Background The Twin Birth Study, a multicenter randomized controlled trial, found no differences in neonatal outcomes in women with twins randomized to planned cesarean or vaginal delivery. Nevertheless, women who present in spontaneous labor might expect a better outcome following a trial of vaginal delivery than undergoing cesarean delivery. In this secondary analysis, we aimed to compare neonatal outcomes of women who presented in spontaneous labor in the two arms of the Twin Birth Study. Methods Women in whom the first twin was in the cephalic presentation were randomized between 32 + 0 and 38 + 6 weeks to planned vaginal delivery or cesarean. The primary outcome was a composite of fetal or neonatal death or serious neonatal morbidity. Results Of the 2804 women included in the Twin Birth Study, 823 women in the planned vaginal delivery arm and 612 in the planned cesarean arm presented in spontaneous labor. Although the odds ratio favored planned vaginal delivery, there was no statistically significant difference in the rate of primary outcome between the vaginal delivery and cesarean arms (1.8% vs 2.7%, respectively; P = 0.16; OR 1.49; 95% CI, 0.87-2.55). Similarly, the rates of the individual components of the primary outcome and of maternal adverse outcome were similar between the two arms. Conclusion In women with twins who present in spontaneous labor between 32 + 0 and 38 + 6 weeks' gestation, where the first twin is cephalic, a policy of planned vaginal delivery or cesarean is not associated with significant differences in neonatal or maternal outcomes.

To compare the incidence and risk factors for gestational diabetes mellitus (GDM) between women with twin and singleton pregnancies. Retrospective study of all women who had a twin or singleton birth in Ontario (2012–2016). Risk ratios (RR) and 95% CIs for GDM (stratified by type of treatment) were adjusted for relevant confounding variables. Multivariable Poisson regression analysis was used to identify risk factors for GDM in twin and singleton gestations. Of 270,843 women who met inclusion criteria, 266,942 (98.6%) and 3901 (1.4%) had a singleton and a twin pregnancy, respectively. Women with twins had a significantly higher risk for overall GDM (aRR = 1.13, 95% CI 1.01–1.28) and diet-treated GDM (aRR = 1.20, 95% CI 1.01–1.42) while the association with insulin-treated GDM was not significant (aRR = 1.07, 95% CI 0.89–1.28). Maternal age ≥ 35 years, non-Caucasian ethnicity and BMI > 30 kg/m2 were independent risk factors for GDM among women with twins and singletons, and the magnitude of the association of these factors with GDM was similar. Women with twins are at increased risk of GDM, mainly due to a higher rate of diet-treated GDM. Despite higher baseline risk of GDM in women with twins, the effect of known risk factors for GDM is similar to that observed in singletons.

A maternal request for an elective CS in the absence of a maternal or fetal indication may raise risk-benefit considerations and ethical concerns for a health care provider. Appropriate counselling of the patient on the risks and benefits in proceeding with a CDMR without medical indication is essential. Providers should have a clear knowledge of the risks and benefits of providing an elective CS without medical indications compared to the risks and benefits of supporting an attempt at vaginal delivery, so that the patient may reach an informed decision. The principle of patient autonomy should be respected but other ethical principles (beneficence, non-maleficence and justice) need to be taken into consideration during the counselling process. There are no studies to estimate maternal and neonatal risks in CDMR. Often studies on CS before the onset of labour are used as surrogates to determine risks and benefits. After exploring the reasons behind the patient's request, and discussing the risks and benefits, if a patient insists on her choice a physician may pursue one of the following two options: 1) Agree to perform the CS after 39+0 weeks gestation; 2) Disagree and refer the patient for a second opinion.

Administrating a single course of antenatal corticosteroids to women at risk of preterm birth between 24 and 34 weeks of gestation has been shown to decrease neonatal morbidity and mortality. There is evidence that the optimal timing for the administration of antenatal corticosteroids is within 1-7 days before birth as the effect of antenatal corticosteroids has been shown to decline 7 days after administration. Therefore, given that antenatal corticosteroids are the single most effective intervention in cases of preterm birth, efforts should be made to optimize the timing of administration of antenatal corticosteroids.To test the hypothesis that the timing of antenatal corticosteroids in women with vaginal bleeding due to placenta previa or low-lying placenta can be optimized by identifying women at low risk of imminent delivery.This was a retrospective cohort study of all women admitted to a tertiary referral center at 24-34 weeks' gestation with vaginal bleeding due to placenta previa or low-lying placenta between 2003 and 2014. Multivariable logistic regression analysis was used to identify factors that are independently associated with delivery within 14 days from admission.A total of 202 women who met the inclusion criteria were admitted with vaginal bleeding in the presence of placenta previa or low-lying placenta during the study period, of whom 31 (15.3%) and 44 (21.8%) gave birth within 7 and 14 days from admission, respectively. The following factors were independently associated with delivery within 14 days from admission: complete placenta previa (odds (OR) 3.57, 95%CI 1.57-9.03), severe bleeding at presentation (OR 17.14, 95%CI 2.92-100.70), uterine contractions at presentation (OR 6.02, 95%CI 1.91-19.00), and cervical length25 mm at presentation (OR 6.33, 95%CI 1.37-29.11). A predictive test based on the presence of ≥1 of these risk factors was associated with a sensitivity of 90.9% and a negative predictive value of 94.6% for delivery within 14 days of presentation.In women presenting with vaginal bleeding due to placenta previa or low-lying placenta, it seems possible to identify a subgroup of women in whom the likelihood of delivery within 14 days is low. This information may allow for selective (rather than routine) administration of antenatal corticosteroids in this scenario, and may thereby contribute to the optimization of the timing of administration of antenatal corticosteroids.

Gestational diabetes mellitus is associated with accelerated fetal growth in singleton pregnancies but may affect twin pregnancies differently because of the slower growth of twin fetuses during the third trimester of pregnancy and their greater predisposition to fetal growth restriction.This study aimed to evaluate the association of gestational diabetes mellitus with longitudinal fetal growth in twin pregnancies and to compare this association with that observed in singleton pregnancies.This was a retrospective cohort study of all women with a singleton or twin pregnancy who were followed up at a single tertiary referral center between January 2011 and April 2020. Data on estimated fetal weight and individual fetal biometric indices were extracted from ultrasound examinations of eligible women. Generalized linear models were used to model and compare the change in fetal weight and individual biometric indices as a function of gestational age between women with and without gestational diabetes mellitus in twin pregnancies and between women with and without gestational diabetes mellitus in singleton pregnancies. The primary outcome was estimated fetal weight as a function of gestational age. The secondary outcomes were longitudinal growth of individual fetal biometric indices and the rate of small for gestational age and large for gestational age at birth.A total of 26,651 women (94,437 ultrasound examinations) were included in the analysis: 1881 with a twin pregnancy and 24,770 with a singleton pregnancy. The rate of gestational diabetes mellitus in the twin and singleton groups was 9.6% (n=180) and 7.6% (n=1893), respectively. The estimated fetal weight in singleton pregnancies with gestational diabetes mellitus was significantly higher than that in pregnancies without gestational diabetes mellitus (P.001) starting at approximately 30 weeks of gestation. The differences remained similar after adjusting for maternal age, chronic hypertension, nulliparity, and neonatal sex (P.001). In twin pregnancies, fetal growth was similar between pregnancies with and without gestational diabetes mellitus (P=.105 and P=.483 for unadjusted and adjusted models, respectively). The findings were similar to the association of gestational diabetes mellitus with the risk of large for gestational fetuses and the growth of each biometric index. When stratified by type of gestational diabetes mellitus treatment, twin pregnancies with gestational diabetes mellitus was associated with accelerated fetal growth only in the subgroup of women with medically treated gestational diabetes mellitus (P.001), which represented 12% (n=21) of the twin pregnancy group with gestational diabetes mellitus.In contrast to singleton pregnancies, twin pregnancies with gestational diabetes mellitus is less likely to be associated with accelerated fetal growth. This finding has raised the question of whether the diagnostic criteria for gestational diabetes mellitus and the blood glucose targets in women diagnosed with gestational diabetes mellitus should be individualized for twin pregnancies.

To examine rates and determinants of mother's own milk (MOM) feeding at hospital discharge in a cohort of infants born very preterm within the Canadian Neonatal Network (CNN).This was a population-based cohort study of infants born at33 weeks of gestation and admitted to neonatal intensive care units (NICUs) participating in the CNN between January 1, 2015, and December 31, 2018. We examined the rates and determinants of MOM use at discharge home among the participating NICUs. We used multivariable logistic regression analysis to identify independent determinants of MOM feeding.Among the 6404 infants born very preterm and discharged home during the study period, 4457 (70%) received MOM or MOM supplemented with formula. Rates of MOM feeding at discharge varied from 49% to 87% across NICUs. Determinants associated with MOM feeding at discharge were gestational age 29-32 weeks compared with26 weeks (aOR 1.56, 95% CI 1.25-1.93), primipara mothers (aOR 2.12, 95% CI 1.86-2.42), maternal diabetes (aOR 0.79, 95% CI 0.66-0.93), and maternal smoking (aOR 0.27, 95% CI 0.19-0.38). Receipt of MOM by day 3 of age was the major predictor of breast milk feeding at discharge (aOR 3.61, 95% CI 3.17-4.12).Approximately two-thirds of infants born very preterm received MOM at hospital discharge, and rates varied across NICUs. Supporting mothers to provide breast milk in the first 3 days after birth may be associated with improved MOM feeding rates at discharge.

Intertwin size discordance is an independent risk factor for adverse neonatal outcomes in twin pregnancies. However, size discordance at a given point in gestation fails to take into consideration information, such as the timing of onset and the rate of progression of discordance, that may be of prognostic value.In this study, we aimed to identify distinct patterns of discordant fetal growth in twin pregnancies and to determine whether these patterns are predictive of adverse pregnancy outcomes.This was a retrospective cohort study of women with twin pregnancies in a single tertiary referral center between January 2011 and April 2020, who had at least 3 ultrasound examinations during pregnancy that included assessment of fetal biometry. Size discordance was calculated at each ultrasound examination, and pregnancies were classified into 1 of 4 predetermined patterns based on the timing of onset and the progression of discordance: pattern 1, no significant discordance group (referent); pattern 2, early (24 weeks' gestation) progressive discordance group; pattern 3, early discordance with plateau group; or pattern 4, late (≥24 weeks' gestation) discordance group. The associations of discordance pattern (using pattern 1 as referent) with preterm birth, preeclampsia, size discordance at birth, and birthweight10th percentile were expressed as adjusted relative risk with 95% confidence intervals and were compared with those observed for a single measurement of size discordance at 32 weeks' gestation.Of 2075 women with a twin gestation who were identified during the study period, 1059 met the study criteria. Of the 1059 women, 599 (57%) were classified as no significant discordance (pattern 1), 23 (2%) as early progressive discordance (pattern 2), 160 (15%) as early discordance with plateau (pattern 3), and 277 (26%) as late discordance (pattern 4). The associations of discordance pattern with preterm birth at34 weeks' gestation and preeclampsia were strongest for pattern 2 (rates of 43% [adjusted relative risk, 3.43; 95% confidence interval, 2.10-5.62] and 17% [adjusted relative risk, 5.81; 95% confidence interval, 2.31-14.60], respectively), intermediate for pattern 3 (rates of 23% [adjusted relative risk, 1.82; 95% confidence interval, 1.28-2.59] and 6% [adjusted relative risk, 2.08; 95% confidence interval, 1.01-4.43], respectively), and weakest for pattern 4 (rates of 12% [adjusted relative risk, 0.96; 95% confidence interval, 0.65-1.42] and 4% [adjusted relative risk, 1.41; 0.68-2.92], respectively). In contrast, a single measurement of size discordance at 32 weeks' gestation showed no association with preeclampsia and only a weak association with preterm birth at34 weeks' gestation.We identified 4 distinct discordance growth patterns among twins that demonstrated a dose-response relationship with adverse outcomes and seemed to be more informative than a single measurement of size discordance.

Background One of the controversies in the management of twin gestations relates to mode of delivery, especially when the second twin is in a nonvertex presentation (Vertex/nonVertex pairs) and birth is imminent at extremely low gestation. Objective We hypothesized that, for Vertex/nonVertex twins born before 28 weeks’ gestation, cesarean delivery would be associated with a lower risk of adverse neonatal outcomes than trial of vaginal delivery. Our aim was to test this hypothesis by comparing the neonatal outcomes of Vertex/nonVertex twins born before 28 weeks’ gestation by mode of delivery using a large national cohort. Study Design This work is a retrospective cohort study of all twin infants born at 240/7 to 276/7 weeks’ gestation and admitted to level III neonatal intensive care units participating in the Canadian Neonatal Network (2010–2017). Exposure is defined a trial of vaginal delivery for Vertex/nonVertex twins. Nonexposed (control) groups are defined as cases where both twins were delivered by cesarean delivery, either in vertex or nonvertex presentation (control group 1) or owing to the nonvertex presentation of the first twin (control group 2). Outcome measures are defined as a composite of neonatal death, severe neurologic injury, or birth trauma. Results A total of 1082 twin infants (541 twin pairs) met the inclusion criteria: 220 Vertex/nonVertex pairs, of which 112 had a trial of vaginal delivery (study group) and 108 had cesarean delivery for both twins (control group 1); 170 pairs with the first twin in nonvertex presentation, all of which were born by cesarean delivery (control group 2); and 151 pairs with both twins in vertex presentation (vertex or nonvertex). In the study group, the rate of urgent cesarean delivery for the second twin was 30%. The rate of the primary outcome in the study group was 42%, which was not significantly different compared with control group 1 (37%; adjusted relative risk, 0.93; 95% confidence interval, 0.71–1.22) or control group 2 (34%; adjusted relative risk, 1.20; 95% confidence interval, 0.92–1.58). The findings remained similar when outcomes were analyzed separately for the first and second twins. Conclusion For preterm Vertex/nonVertex twins born at

Our aim was to compare perinatal outcomes in twin pregnancies complicated by premature asymptomatic cervical dilatation treated with rescue cerclage and expectant management.A retrospective cohort study was conducted at a single tertiary referral center between 2003 and 2014 and included all women with twins found to have a dilated cervix with intact membranes before 25-week gestation. Pregnancy outcomes were compared between women with rescue cerclage and those managed expectantly. A total of 36 women were eligible for the study, 27 (75.0%) of whom had a rescue cerclage compared to 9 (25.0%) women managed expectantly. Student's t-test was used to compare continuous variables between the groups and the chi-square and Fisher's exact tests were used for categorical variables as appropriate. Statistical analysis was performed with the SPSS v21.0 software (IBM Corp; Armonk, NY). Differences were considered significant when the p value was less than .05.Among the 27 women with a rescue cerclage, the mean gestational age at time of cerclage insertion was 21.5 ± 2.6 weeks. The intervention and control groups were similar with respect to the degree of cervical dilatation at presentation (2.6 ± 1.3 versus 3.0 ± 1.5 cm, p = .5). Women in the cerclage group gave birth at a more advanced gestation (28.9 ± 6.1 versus 24.2 ± 2.6 weeks, respectively, p = .03) and were less likely to give birth at34 and 28 weeks (66.7 versus 100.0%, p = .046, and 59.3 versus 100.0%, p = .02, respectively). The mean latency from the placement of cerclage to delivery was 7.3 ± 5.5 weeks. Similar findings were observed when analysis was limited to women with cervical dilatation of ≤3 cm at presentation.In asymptomatic women with twin pregnancies and cervical dilatation before 25 weeks of gestation, rescue cerclage can prolong pregnancy and improve perinatal outcomes when compared to expectant management.

To assess the predictive accuracy of serial measurements of cervical length (CL) for preterm birth in asymptomatic women with triplet pregnancy.A retrospective study of women with triplets who underwent serial sonographic measurements of CL until 28-32 weeks of gestation. The predictive accuracy of CL for preterm birth was determined at 4 periods along gestation: 18-20 weeks (period 1), 21-24 weeks (period 2), 25-27 weeks (period 3) and 28-32 weeks (period 4).A total of 431 measurements of CL from were analyzed. CL decreased in a linear manner across gestation: 40.8 ± 7.1 mm, 36.5 ± 8.4 mm, 29.9 ± 11.4 mm and 25.0 ± 11.8 mm in periods 1, 2, 3 and 4, respectively. The difference in CL between women who did and did not deliver prematurely was small before 25 weeks (periods 12) but became more pronounced later in pregnancy (periods 34), mainly due to a rapid cervical shortening between periods 2 and 3 (shortening rate -29.0 ± 20.0% vs. -12.6 ± 20.5%, respectively, p = .01). The best predictors of preterm birth were either a single measurement of CL during period 3 or the degree of cervical shortening between periods 2 and 3.Care providers should be aware of the limited predictive value of cervical length before 25 + 0 weeks in triplet pregnancies.

Objectives The Twin Birth Study was a multicenter randomized trial which found that a planned cesarean section does not result in a lower risk of adverse outcomes than planned vaginal delivery in twin pregnancies. Yet, since the study's inclusion criteria was limited to birth ≥32 weeks, the optimal mode of delivery at Methods An anonymous online questionnaire was sent to MFM specialists and OBs across Canada (n=90) that focused on their practice regarding the management of twin delivery before 32 weeks with the first twin in vertex (Vx) presentation and no other contraindications for a trial of labor (TOL). Data were stratified by gestational age at birth ( Results Overall, 70 individuals (77.8%) participated in survey, of them 48 (68.5%) were MFMs. Fifty-two (74.2%) have been practicing OBs/MFMs for >10 years. In the case of twin birth Conclusions In early preterm twins, the recommendation for TOL by either MFMs or OBs appears to be influenced more by the presentation of the second twin than by gestational age at delivery. More evidence is needed to assess the safety of TOL in early preterm twins.

Objectives Early and late hypertensive disorders in pregnancy (HDP) are different entities in singleton gestations, with earlier onset associated with higher rates of placental maternal vascular malperfusion lesions (MVMs). It is still not known if this distinction apply for twin gestations as well. Methods Retrospective study of women with DCDA twin gestations and HDP (2001–2015), with a placental pathology evaluation. Placental lesions were classified according to the Amsterdam criteria. Pregnancies with early onset HDP (≤34 weeks) were compared with pregnancies with late onset HDP (>34 weeks). Results Out of 1655 twin deliveries, 161 (9.7%) were complicated by HDP: 77 (47.8%) had preeclampsia, and 84 (52.2%) had gestational hypertension. Forty patients (24.8%) had early onset HDP. Early HDP was associated with a higher rate of 1 MVMs (p=0.01), ≥2 MVMs (p=0.009) and with a lower rate of chronic villitis (p=0.02). In multivariable analysis, using late HDP as reference, early HDP was associated with a higher prevalence of ≥1 MVMs (aOR 1.9, 95% CI 1.1–3.5, p=0.03) and ≥2 MVMs (aOR 2.6, 95% CI 1.05–6.3, p=0.04). Early HDP was also less associated with chronic villitis (aOR 0.2, 95% CI 0.05–0.9), as chronic villitis is usually associated with a more advanced gestational age. Conclusions While the mechanism underlying HDP in singleton and twins’ gestations may be different, similar to singleton pregnancies, early onset (≤34 weeks gestation) of HDP in twins’ gestation is associated with a higher prevalence of MVM's, suggesting of reduced placental perfusion in early onset HDP in twins.

Objectives Numerous formulas for estimated fetal weight (EFW) calculations have been proposed over the years but have not been validated in patients with preterm premature rupture of membranes (PPROM). The study objective was to compare the accuracy of the various sonographic EFW formulas in patients with PPROM. Methods This was a retrospective cohort study of women with PPROM and singleton gestations who were admitted between 220–330 weeks to a single, university-affiliated tertiary referral centre between 2003–2017. All women had a sonogram for EFW within 14 days of delivery by standard biometry (biparietal diameter, head circumference, abdominal circumference, and femur length). We compared the accuracy of 21 previously published EFW formulas in the setting of PPROM by comparing the correlation with actual birth weight and calculating the systematic error (SE), random error (RE), proportion of estimates (POE) within 10% of birth weight and Euclidean distance. Results Overall, 565 women were included in the study. Most formulas had strong correlation with actual birth weight (19/21 formulas with r >0.9). The mean SE was -4.30% and mean RE 14.48%. The formula that performed the best, by the highest POE and lowest Euclidean distance was that of Ott (1986), utilizing abdominal and head circumferences, and femur length, yet all of the first 10 ranking formulas (including the mostly used Hadlock IV) performed quite similarly with minimal differences between them. Conclusions Most formulas accurately calculation EFW in PPROM patients, but the Ott (1986) formula ranked highest, thus it may be the preferred formula to use in this population.

Objective This study sought to test the hypothesis that among multiparous women requiring cervical ripening, mechanical ripening with a Foley catheter is more effective than prostaglandin preparations. Methods This was a retrospective analysis of multiparous women with a singleton gestation who required cervical ripening in a single tertiary center from 2014 to 2019. Women who underwent cervical ripening with a Foley catheter (Foley group) were compared with women who underwent cervical ripening using a controlled-release dinoprostone vaginal insert (PGE2-CR group) or dinoprostone vaginal gel (PGE2-gel group). The primary outcome was the ripening-to-delivery interval. Results A total of 229 women met the study criteria (Foley group: 95; PGE2-CR group: 83; PGE2-gel group: 51). Women in the Foley group had a significantly shorter ripening-to-delivery interval compared with women in the PGE2-CR group (16.2 ± 9.2 hours vs. 27.0 ± 14.8 hours; P Conclusion In multiparous women requiring cervical ripening, all methods of cervical ripening have a similar success rate. However, the use of a PGE2-CR insert is associated with a considerably longer interval to delivery compared with a Foley catheter or PGE2 gel.

OBJECTIVE To provide evidence-based guidelines for the provision of a trial of labour after Caesarean section. OUTCOMES Fetal and maternal morbidity and mortality associated with vaginal birth after Caesarean and repeat Caesarean section. EVIDENCE MEDLINE database was searched for articles published from January 1, 1995, to October 31, 2017 using the key words "vaginal birth after Caesarean (Cesarean) section." The quality of evidence is described using the Evaluation of Evidence criteria outlined in the Report of the Canadian Task Force on the Periodic Health Exam. VALIDATION These guidelines were approved by the Clinical Practice Obstetrics Committee and the Board of the Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS