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Associations between pregnancy weight gain and adverse outcomes may be spurious owing to confounding by factors not typically measured in cohort studies. We determined the extent to which the addition of detailed behavioral, psychosocial, and environmental measurements to commonly available covariates improved control of confounding.We used data from a prospective US pregnancy cohort study (2010-2013, n = 8978). We calculated two propensity scores for low and high pregnancy weight gain (vs. adequate gain) using 11 standard confounders (e.g., age and education). We examined the balance of characteristics between weight gain groups before and after propensity score matching. We used negative binomial regression to estimate the association between weight gain and small- and large-for-gestational-age birth, preterm birth, and unplanned cesarean delivery, controlling for propensity score. To this model, we then added 17 detailed behavioral, psychosocial, and environmental measurements ("fully adjusted"). We calculated the risk ratio owing to confounding as the ratio of the standard confounder-adjusted risk ratio to the fully adjusted risk ratio.There were minimal imbalances between weight gain groups in detailed measures after matching for a propensity score of standard covariates. Accordingly, the inclusion of detailed covariates had minimal impact on estimated associations between low or high pregnancy weight gain and adverse pregnancy outcomes: risk ratios owing to confounding were null for all outcomes (e.g., 1.1 [95% CI = 1.0, 1.1] for low weight gain and preterm birth).Adjustment for detailed behavioral, psychosocial, and environmental measurements had minimal impact on estimated associations between pregnancy weight gain and adverse perinatal outcomes.

Gestational diabetes mellitus (GDM) is a common pregnancy complication associated with adverse consequences for the mother and offspring in both short and long term. The aim of this study was to investigate associations between risk of GDM and gestational weight gain in early pregnancy and before diagnosis.Our population-based cohort study included 131 164 singleton pregnancies in the Stockholm-Gotland region in Sweden from 2008 through 2013. The exposures were weight gain in early pregnancy (22 weeks) and weight gain before diagnosis, standardized into gestational age-specific z scores. The outcome was GDM. We used logistic regression models with a generalized estimating equations method to estimate odds ratios with 95% confidence intervals for GDM, stratified by early-pregnancy body mass index (BMI) category.Above average weight gain before diagnosis (z score 0) was associated with increased risk of GDM among all BMI groups except for obese III. Early gestational weight gain above average was associated with increased risk for GDM in overweight women. Below average weight gain before diagnosis (z score 0) was only associated with decreased risk of GDM in obese III. Early gestational weight gain below average was associated with reduced risks of GDM in obese class I, II, and III women.The risk of GDM increased with higher weight gain before diagnosis in all BMI groups except obese class III, whereas the risk was reduced with lower weight gain before diagnosis in obese III women only. The risk of GDM increased with higher early gestational weight gain in overweight women, while the risk was reduced with lower early gestational weight gain among obese women. Obese women may benefit from lower weight gain, especially in early pregnancy.

Both inadequate and excessive maternal weight gain are correlated with preterm delivery in singleton pregnancies, yet this relationship has not been adequately studied in twins. We investigated the relationship between time-varying maternal weight gain and gestational age at delivery in twin pregnancies and compared to that in singletons delivered in the same study population. We used serial weight measurements abstracted from charts for twin and singleton pregnancies delivered from 1998-2013 in Pittsburgh, Pennsylvania. Our exposure was time-varying weight gain z-score calculated using gestational age-standardized and pre-pregnancy body mass index-stratified twin- and singleton-specific charts, and our outcome was gestational age at delivery. Our analyses used a flexible extension of the Cox proportional hazards model that allowed for non-linear and time-dependent effects. We found a U-shaped relationship between weight gain z-score and gestational age at delivery among twin pregnancies (lowest hazard of delivery observed at z-score=1.2), which we attributed to increased hazard of early preterm spontaneous delivery among pregnancies with low weight gain and increased hazard of late preterm delivery without labour among pregnancies with high weight gain. Our findings may be useful for updating provisional guidelines for maternal weight gain in twin pregnancies.

Objective To assess the presentation of risk information in American College of Obstetricians and Gynecologists (ACOG) obstetrical Practice Bulletins. Methods We reviewed B- and C-graded recommendations in Practice Bulletins published from January 2017 to March 2020. We calculated the proportion of recommendations and outcomes that were presented numerically and, of these, the proportion that were presented in accordance with best practices of risk communication – in absolute formats, or as absolute changes in risk from baseline risks. We categorized outcomes as harms or benefits to compare their risk presentation. Results In 21 obstetrical Practice Bulletins, there were 125 recommendations, with 46 (37%) describing risks numerically. Sixteen of these 46 recommendations (35%) presented an absolute change in risk from a baseline risk. For harms, 65% were presented as absolute risks and 25% as relative risks. For benefits, this was 55% and 48% respectively. Conclusion Most recommendations do not present numeric risk information. Of those that do, most do not use absolute risk measures. Practice implications Obstetrical practice guidelines should present numerical risk information wherever possible to support recommendations, increasing the use of absolute risk formats and absolute changes from baseline risks to increase risk comprehension.

Antenatal corticosteroids reduce respiratory morbidity in preterm infants, but their use during late preterm gestation (34-36 weeks) is limited because their safety for longer-term child neurodevelopment is unclear. We sought to determine if fetuses with higher probability of exposure to antenatal corticosteroids had increased rates of prescriptions for attention-deficit/hyperactivity disorder (ADHD) medication in childhood, using a quasiexperimental design that better controls for confounding than existing observational studies.We identified 16 358 children whose birthing parents were admitted for delivery between 31 + 0 (31 weeks, 0 days) and 36 + 6 weeks' gestation in 2000-2013, using a perinatal data registry from British Columbia, Canada, and linked their records with population-based child ADHD medication data (2000-2018). We used a regression discontinuity design to capitalize on the fact that pregnancies presenting for delivery immediately before and immediately after the clinical cut-off for antenatal corticosteroid administration of 34 + 0 weeks' gestation have very different levels of exposure to corticosteroids, but are otherwise similar with respect to confounders.Over a median follow-up period of 9 years, 892 (5.5%) children had 1 or more dispensations of ADHD medication. Children whose birthing parents were admitted for delivery just before the corticosteroid clinical cut-off of 34 + 0 weeks' gestation did not appear to be more likely to be prescribed ADHD medication than those admitted just after the cut-off (rate ratio 1.1, 95% confidence interval [CI] 0.8 to 1.6; 1.3 excess cases per 100 children, 95% CI -2.5 to 5.7).We found little evidence that children with higher probability of exposure to antenatal corticosteroids have higher rates of ADHD prescriptions in childhood, supporting the safety of antenatal corticosteroids for this neurodevelopmental outcome.

Objectives. To determine if the introduction of New York State’s 8-week paid family leave policy on January 1, 2018, reduced rates of hospitalizations with respiratory syncytial virus (RSV) bronchiolitis or any acute lower respiratory tract infection among young infants. Methods. We conducted an interrupted time series analysis using New York State population-based, all-payer hospital discharge records, October 2015 to December 2019. We estimated the change in monthly hospitalization rates for RSV bronchiolitis and for any acute lower respiratory tract infection among infants aged 8 weeks or younger after the introduction of paid family leave while controlling for temporal trends and RSV seasonality. We modeled RSV hospitalization rates in infants aged 1 year as a control. Results. Hospitalization rates for RSV bronchiolitis and any acute lower respiratory tract infection decreased by 30% after the introduction of paid family leave (rate ratio [RR] = 0.71; 95% confidence interval [CI] = 0.54, 0.94; and RR = 0.72; 95% CI = 0.59, 0.88, respectively). There were no such reductions in infants aged 1 year (RR = 0.98; 95% CI = 0.72, 1.33; and RR = 1.17; 95% CI = 1.03, 1.32, respectively). Conclusions. State paid family leave was associated with fewer RSV-associated hospitalizations in young infants. (Am J Public Health. 2022;112(2):316–324. https://doi.org/10.2105/AJPH.2021.306559 )

The inherent correlation between the total amount of weight gained in pregnancy and the duration of pregnancy creates major methodological challenges in the study of pregnancy weight gain. In this issue (Am J Epidemiol. 2022;191(10):1687–1699), Richards et al. examine the extent to which different measures of pregnancy weight gain (including covariate adjustment for gestational age and standardizing weight gain for gestational duration using a pregnancy weight gain chart) are able to disentangle the effects of low weight gain on perinatal health from the role of younger gestational age at delivery for 3 outcomes: small-for-gestational-age birth, cesarean delivery, and low birth weight. While methodological research to understand how to best disentangle the effects of gestational weight gain from pregnancy duration is valuable, we argue that the practical utility of this type of research would be increased by aligning the specific research questions more closely with health outcomes on which evidence is most needed—those not considered in current weight gain guidelines due to lack of high-quality evidence (such as pre-eclampsia and stillbirth). Further, evaluations of weight gain charts should separate out the potential for bias introduced by the use of a normative chart per se from the use of a chart unsuitable for the study population.

BACKGROUND: Although gestational diabetes might be more common in twin versus singleton pregnancies, reasons for this are unclear. We evaluated the extent to which the relationship is explained by higher mid-pregnancy weight gain within normal weight and overweight pre-pregnancy body mass index (BMI) strata. METHODS: We analyzed serial weights and glucose screening and diagnostic data abstracted from medical charts for twin (n=1397) and singleton (n=3117) pregnancies with normal or overweight pre-pregnancy BMI delivered from 1998–2013 at Magee Women’s Hospital in Pennsylvania. We used causal mediation analyses to estimate the total effect of twin versus singleton pregnancy on gestational diabetes, as well as those mediated (natural indirect effect) and not mediated (natural and controlled direct effects) by pathways involving mid-pregnancy weight gain. RESULTS: Odds of gestational diabetes were higher among twin pregnancies [odds ratios (ORs) for total effect=2.83 (95% CI 1.54; 5.19) for normal weight and 2.09 (95% CI 1.16; 3.75) for overweight pre- pregnancy BMI], yet there was limited evidence that this relationship was mediated by weight gain [ORs for natural indirect effect=1.21 (95% CI 0.95; 1.54) for normal weight and 1.06 (95% CI 0.92; 1.21) for overweight pre-pregnancy BMI], and more evidence of mediation via other pathways [ORs for natural direct effect=2.34 (95% CI 1.24; 4.40) for normal weight and 1.97 (95% CI 1.08; 3.60) for overweight pre-pregnancy BMI]. CONCLUSIONS: While twin pregnancies with normal weight or overweight pre-pregnancy BMI experience higher odds of gestational diabetes versus singletons, most of this effect is explained by pathways not involving mid-pregnancy weight gain.

Placental abnormalities have been described in clinical convenience samples, with predominately adverse outcomes. Few studies have described placental patterns in unselected samples.We aimed to investigate associations between co-occurring placental features and adverse pregnancy outcomes in a prospective cohort of singletons.Data were from the Safe Passage study (U.S. and South Africa, 2007-2015). Before 24 weeks' gestation, participants were randomly invited to donate placental tissue at delivery for blinded, standardised pathological examination. We used hierarchical clustering to construct statistically derived groups using 60 placental features. We estimated associations between the placental clusters and select adverse pregnancy outcomes, expressed as unadjusted and adjusted risk ratios (RRs) and robust 95% confidence intervals (CI).We selected a 7-cluster model. After collapsing 2 clusters to form the reference group, we labelled the resulting 6 analytic clusters according to the overarching category of their most predominant feature(s): severe maternal vascular malperfusion (n = 117), fetal vascular malperfusion (n = 222), other vascular malperfusion (n = 516), inflammation 1 (n = 269), inflammation 2 (n = 175), and normal (n = 706). Risks for all outcomes were elevated in the severe maternal vascular malperfusion cluster. For instance, in unadjusted analyses, this cluster had 12 times the risk of stillbirth (RR 12.07, 95% CI 4.20, 34.68) and an almost doubling in the risk of preterm delivery (RR 1.93, 95% CI 1.27, 2.93) compared with the normal cluster. Small infant size was more common among the abnormal clusters, with the highest unadjusted RRs observed in the fetal vascular malperfusion cluster (small for gestational age birth RR 2.99, 95% CI 2.24, 3.98, head circumference10th percentile RR 2.86, 95% CI 1.60, 5.12). Upon adjustment for known risk factors, most RRs attenuated but remained1.Our study adds to the growing body of epidemiologic research, finding adverse pregnancy outcomes may occur through etiologic mechanisms involving co-occurring placental abnormalities.

Weekly iron-folic acid (IFA) supplements are recommended for all menstruating women in countries where anemia prevalence is ≥20%; however, it is unknown whether the inclusion of folic acid in weekly IFA supplements reduces anemia.We examined whether the inclusion of folic acid in weekly IFA supplements conferred any benefit on hemoglobin (Hb) concentration, anemia reduction, or iron status [ferritin and soluble transferrin receptor (sTfR)], over iron alone.In this secondary analysis of a randomized controlled trial in Malaysia, n = 311 nonpregnant women (18-45 y old) received 60 mg Fe with either 0, 0.4, or 2.8 mg folic acid once-weekly for 16 wk. Fasting blood was collected at baseline and 16 wk. A generalized linear model (normal distribution with identity link) was used to assess Hb concentration at 16 wk (primary outcome).At baseline, 84% of women had low folate status (plasma folate 14 nmol/L). At 16 wk, marginal mean (95% CI) Hb was 131 (130, 133), 131 (129, 132), and 132 (130, 133) g/L; ferritin was 58.2 (53.9, 62.5), 56.5 (52.2, 60.9), and 58.0 (53.7, 62.3) μg/L; and sTfR was 5.8 (5.5, 6.1), 5.8 (5.5, 6.1), and 5.9 (5.6, 6.2) mg/L in the 0, 0.4, and 2.8 mg/wk groups, respectively, with no differences between groups (P 0.05). Baseline plasma folate concentration did not modify the effect of treatment on Hb concentration at 16 wk. Among all women, the risks of anemia [risk ratio (RR): 0.65; 95% CI: 0.45, 0.96; P = 0.03] and iron deficiency based on ferritin (RR: 0.30; 95% CI: 0.20, 0.44; P 0.001) were lower at 16 wk than at baseline.Despite the low folate status among these nonpregnant Malaysian women, the inclusion of folic acid in weekly IFA supplements did not reduce anemia or improve iron status, over iron alone. However, the benefits of folic acid for neural tube defect prevention still warrant its retention in weekly IFA supplements.This trial was registered at www.anzctr.org.au as ACTRN12619000818134.

Objectives: To estimate the association between estimated fetal weight (EFW) percentiles on the INTERGROWTH-21st and WHO fetal growth charts and kindergarten-age childhood development, and identify the charts’ percentile cut-offs that best predict kindergarten-age developmental challenges. Design: Retrospective cohort linkage study. Setting: Obstetrical ultrasound department of BC Women’s Hospital, Vancouver, Canada. Population or Sample: Non-anomalous, singleton fetuses scanned ≥ 28 weeks’ gestation, 2000-2011 (n=3418). Methods: We classified EFWs into percentiles using the INTERGROWTH-21st and WHO charts. We used generalized additive modelling to link EFW percentile with routine province-wide kindergarten readiness test results. We calculated the AUC, as well as other measures of diagnostic accuracy with 95% confidence intervals (CI) at select percentile cut-points of the charts. Main Outcome Measures: Total Early Development Instrument (EDI) score (/50). Secondary outcomes: EDI sub-domain scores for language and cognitive development, and for communication skills and general knowledge; designation of ‘developmentally vulnerable’ or ‘special needs’. Results: Fetuses with lower EFW percentiles had systematically lower EDI scores and increased risks of developmental vulnerability. However, the clinical significance of differences was modest in magnitude: e.g., total EDI score -2.8 [95% CI: -5.1, -0.5] in children with an EFW 3-9th percentile of INTERGROWTH chart (vs. reference of 31-90th). The charts’ predictive abilities for adverse child development were limited (e.g., AUC

Background Monitoring gestational weight gain (GWG) is fundamental to ensure a successful pregnancy for the mother and the offspring. There are several international GWG charts, but just a few for low- and middle-income countries. Objectives To construct GWG charts according to pre-pregnancy BMI for Brazilian women. Methods This is an individual patient data analysis using the Brazilian Maternal and Child Nutrition Consortium data, comprising 21 cohort studies. External validation was performed using “Birth in Brazil,” a nationwide study. We selected adult women with singleton pregnancies who were free of infectious and chronic diseases, gestational diabetes, and hypertensive disorders; who delivered a live birth at term; and whose children were adequate for gestational age, and with a birth weight between 2500–4000 g. Maternal self-reported pre-pregnancy weight and weight measured between 10–40 weeks of gestation were used to calculate GWG. Generalized Additive Models for Location, Scale and Shape were fitted to create GWG charts according to gestational age, stratified by pre-pregnancy BMI. Results The cohort included 7086 women with 29,323 weight gain measurements to construct the charts and 4711 women with 31,052 measurements in the external validation. The predicted medians for GWG at 40 weeks, according to pre-pregnancy BMI, were: underweight, 14.1 kg (IQR, 10.8–17.5 kg); normal weight, 13.8 kg (IQR, 10.7–17.2 kg); overweight, 12.1 kg (IQR, 8.5–15.7 kg); obesity, 8.9 kg (IQR, 4.8–13.2 kg). The 10th, 25th, 50th, 75th, and 90th percentiles were estimated. Results for internal and external validation showed that the percentages below the selected percentiles were close to those expected. Conclusions The charts proposed provide a description of GWG patterns according to gestational age and pre-pregnancy BMI among healthy Brazilian women with good neonatal outcomes. The external validation indicates that this new tool can be used to monitor GWG in the primary health-care setting and to test potential recommended values.

Objective: Preliminary findings from selected health systems revealed interruptions in reproductive health care services due to the COVID-19 pandemic. We estimated changes in postpartum contraceptive provision associated with the start of the COVID-19 pandemic in Maine. Methods: We used the Maine Health Data Organization’s All Payer Claims Database for deliveries from October 2015 through March 2021 (n = 45 916). Using an interrupted time-series analysis design, we estimated changes in provision rates of long-acting reversible contraception (LARC), permanent contraception, and moderately effective contraception within 3 and 60 days of delivery after the start of the COVID-19 pandemic. We performed 6- and 12-month analyses (April 2020–September 2020, April 2020–March 2021) as compared with the reference period (October 2015–March 2020). We used Poisson regression models to calculate level-change rate ratios (RRs) and 95% CIs. Results: The 6-month analysis found that provision of LARC (RR = 1.89; 95% CI, 1.76-2.02) and moderately effective contraception (RR = 1.51; 95% CI, 1.33-1.72) within 3 days of delivery increased at the start of the COVID-19 pandemic, while provision of LARC (RR = 0.95; 95% CI, 0.93-0.97) and moderately effective contraception (RR = 1.08; 95% CI, 1.05-1.11) within 60 days of delivery was stable. Rates of provision of permanent contraception within 3 days (RR = 0.70; 95% CI, 0.63-0.78) and 60 days (RR = 0.71; 95% CI, 0.63-0.80) decreased. RRs from the 12-month analysis were generally attenuated. Conclusion: Disruptions in postpartum provision of permanent contraception occurred at the beginning of the COVID-19 pandemic in Maine. Public health policies should include guidance for contraceptive provision during public health emergencies and consider designating permanent contraception as a nonelective procedure.

Objective: Current guidelines for maternal weight gain in twin pregnancy were established in the absence of evidence on its longer-term consequences for maternal and child health. We evaluated the association between weight gain in twin pregnancies and the risk of excess maternal postpartum weight increase, childhood obesity, and child cognitive ability. Methods: We used 5-year follow-up data from 1000 twins born to 450 mothers in the Early Childhood Longitudinal Study – Birth Cohort, a nationally representative U.S. cohort of births in 2001. Pregnancy weight gain was standardized into gestational age- and prepregnancy body mass index (BMI)-specific z-scores. Excess postpartum weight increase was defined as ≥10 kg increase from prepregnancy weight. We defined child overweight/obesity as BMI ≥ 85th percentile, and low reading and math achievement as scores one standard deviation below the mean. We used survey-weighted multivariable modified Poisson models with a log link to relate gestational weight gain z-score with each outcome. Results: Excess postpartum weight increase occurred in 40% of mothers. Approximately 28% of twins were affected by overweight/obesity, and 16% and 14% had low reading and low math scores. There was a positive linear relationship between pregnancy weight gain and both excess postpartum weight increase and childhood overweight/obesity. Compared with a gestational weight gain z-score 0 SD (equivalent to 20 kg at 37 weeks gestation), a weight gain z-score of +1 SD (27 kg) was associated with 6.3 (0.71, 12) cases of excess weight increase per 1000 women and 4.5 (0.81, 8.2) excess cases of child overweight/obesity per 100 twins. Gestational weight gain was not related to kindergarten academic readiness. Conclusions: The high prevalence of excess postpartum weight increase and childhood overweight/obesity within the recommended ranges of gestational weight gain for twin pregnancies suggests that these guidelines could be inadvertently contributing to longer-term maternal and child obesity.

North American public health guidelines recommend supplementation with an iron-containing prenatal multivitamin throughout pregnancy to meet the RDA of 27 mg of elemental iron daily. However, whether supplementation with standard prenatal multivitamins is sufficient to prevent maternal iron deficiency is unclear, as needs increase substantially with advancing gestation.This study aimed to assess iron status in early and late pregnancy among 60 pregnant women receiving 27 mg/day of elemental iron as part of a randomized trial in Vancouver, Canada.Study visits were conducted at 8-21 (baseline) and 24-38 (endline) weeks of gestation. Venous blood specimens were collected for a complete blood count and measurement of iron and inflammatory biomarkers. Supplementation with any additional iron (beyond 27 mg/day) was reported by participants (treatment with additional iron is recommended if ferritin is30 μg/L). Quantile regression was used to explore predictors of endline ferritin concentrations, including ethnicity, education, income, and baseline ferritin measurement.Overall, 60 and 54 women participated in baseline and endline visits, respectively. Rates of probable iron deficiency (ferritin 30 μg/L) at baseline and endline were 17 (28%) and 44 (81%), respectively. Less than half (n = 18; 41%) of participants with probable iron deficiency at endline reported supplementation with additional iron. Ethnicity was the only significant modifier of endline ferritin, with higher concentrations in those of South, East, and Southeast Asian ethnicity compared to those of European ethnicity (β: 10.4 μg/L; 95% CI: 0.3-20.5).Pregnant individuals may require additional supplemental iron beyond 27 mg to meet requirements in later pregnancy, given the high rates of iron deficiency observed in this clinical trial, despite consumption meeting 100% of the RDA. This trial was registered at clinicaltrials.gov as NCT04022135.

BACKGROUND: Estimation of causal effects of short interpregnancy interval on pregnancy outcomes may be confounded by time-varying factors. These confounders should be ascertained at or before delivery of the first ("index") pregnancy, but are often only measured at the subsequent pregnancy. OBJECTIVES: To quantify bias induced by adjusting for time-varying confounders ascertained at the subsequent (rather than the index) pregnancy in estimated effects of short interpregnancy interval on pregnancy outcomes. METHODS: We analysed linked records for births in British Columbia, Canada, 2004-2014, to women with ≥2 singleton pregnancies (n = 121 151). We used log binomial regression to compare short (

Background Current pregnancy weight gain guidelines were developed based on implicit assumptions of a small group of experts about the relative seriousness of adverse health outcomes. Therefore, they will not necessarily reflect the values of women. Objective To estimate the seriousness of 11 maternal and child health outcomes that have been consistently associated with pregnancy weight gain by engaging patients and health professionals. Methods We collected data using an online panel approach with a modified Delphi structure. We selected a purposeful sample of maternal and child health professionals (n = 84) and women who were pregnant or recently postpartum (patients) (n = 82) in the United States as panellists. We conducted three concurrent panels: professionals only, patients only, and patients and professionals. During a 3-round online modified Delphi process, participants rated the seriousness of health outcomes (Round 1), reviewed and discussed the initial results (Round 2), and revised their original ratings (Round 3). Panellists assigned seriousness ratings (0, [not serious] to 100 [most serious]) for infant death, stillbirth, preterm birth, gestational diabetes, preeclampsia, small-for-gestational-age (SGA) birth, large-for-gestational-age (LGA) birth, unplanned caesarean delivery, maternal obesity, childhood obesity, and maternal metabolic syndrome. Results Each panel individually came to a consensus on all seriousness ratings. The final median seriousness ratings combined across all panels were highest for infant death (100), stillbirth (95), preterm birth (80), and preeclampsia (80). Obesity in children, metabolic syndrome in women, obesity in women, and gestational diabetes had median seriousness ratings ranging from 55 to 65. The lowest seriousness ratings were for SGA birth, LGA birth, and unplanned caesarean delivery (30-40). Conclusion Professionals and women rate some adverse outcomes as being more serious than others. These ratings can be used to establish the range of pregnancy weight gain associated with the lowest risk of a broad range of maternal and child health outcomes.

Supplemental Digital Content is available in the text., Background: Fetal growth standards (prescriptive charts derived from low-risk pregnancies) are theoretically better tools to monitor fetal growth than conventional references. We examined how modifying chart inclusion criteria influenced the resulting curves. Methods: We summarized estimated fetal weight (EFW) distributions from a hospital’s routine 32-week ultrasound in all nonanomalous singleton fetuses (reference) and in those without maternal–fetal conditions affecting fetal growth (standard). We calculated EFWs for the 3rd, 5th, 10th, and 50th percentiles, and the proportion of fetuses each chart classified as small for gestational age. Results: Of 2309 fetuses in our reference, 690 (30%) met the standard’s inclusion criteria. There were no meaningful differences between the EFW distributions of the reference and standard curves (50th percentile: 1989 g reference vs. 1968 g standard; 10th percentile: 1711 g reference vs. 1710 g standard), or the proportion of small for gestational age fetuses (both 9.9%). Conclusions: In our study, there was little practical difference between a fetal growth reference and standard for detecting small infants.

Objective To identify the extent of hospital-to-hospital variation in use of obstetrical blood transfusion. Design Population-based cohort study linking provincial perinatal and blood transfusion registries. Setting British Columbia, Canada, 2004-2015. Population All pregnant women delivering at or beyond 20 weeks' gestation at any British Columbia hospital. Methods Mixed-effects regression models were used to estimate hospital-specific transfusion rates after sequentially accounting for (1) the role of random variation, (2) maternal medical and obstetrical characteristics (i.e. patient case mix) and (3) institutional and delivery factors (such as use of instrumental or caesarean delivery). Main outcome measures Hospital-specific use of obstetrical red blood cell transfusion. Results Among 44 hospitals, crude institutional transfusion rates across the study period ranged from 3.7 to 23.6 per 1000, with an average of 8.3 per 1000. After adjusting for maternal characteristics, institution and delivery risk factors, a nearly three-fold difference in rates between the 10th and 90th percentile remained (5.4-14.5 per 1000). Twelve sites had rates significantly higher or lower than the provincial average. Women residing in remote areas were 2.5-fold (95% CI 1.8-3.5] more likely to receive a blood transfusion than were women residing in metropolitan areas. Conclusions Meaningful variation between hospitals in use of blood transfusion during pregnancy was not explained by differences in patient case-mix or institutional factors, suggesting that over- or under-utilisation of this resource may be occurring in obstetrical care. Tweetable abstract Use of blood transfusion in pregnant women varied broadly between hospitals in British Columbia, Canada.

Recent evidence from the United States and Canada suggests an unexplained increase in small-for-gestational-age (SGA) births (10th percentile). This study aimed to identify reasons for the recent increase in SGA births in Canada.Using Canada's Vital Statistics - Birth Database, the study population included all singleton live births, 2000 to 2016, inclusive. Temporal changes in birth weight (grams), birth weight for gestational age z-scores, and SGA births were examined. Multivariable logistic regression was used to determine if the ncreased risk of an SGA birth over time was eliminated or attenuated by adjusting for selected individual and sociodemographic factors that have previously been associated with SGA births.There were 5,941,820 singleton live births in Canada between 2000 and 2016. Mean birth weight for all births decreased from 3,442 grams in 2000, to 3,367 grams in 2016, while SGA birth increased from 7.2% in 2000 to 8.0% in 2016. The multivariable model showed higher odds of SGA birth among births to parents born outside of Canada, unmarried women, older women, nulliparous women and women residing in low income neighborhoods. After adjusting for sociodemographic factors, the crude 12% increase in odds of SGA birth in 2016 compared to 2000 (95% Confidence Interval (CI): [10 to 14%]) was attenuated, ut not eliminated (adjusted odds ratio for calendar time 1.08 (95% CI: [1.06, 1.10])).This study identified a decrease in fetal size in Canada between 2000 and 2016. The rise in SGA births in Canada was explained only partly as a result of concurrent changes in the demography of childbirth.

Objectives To evaluate the recruitment of pregnant women for a clinical trial in Vancouver, Canada, via social media versus offline methods and to explore optimization of social media campaigns. Methods Facebook was used to run nine social media campaigns (15 weeks total, CA$675). Offline methods were used concurrently over 64 weeks (printing costs: CA$300). The cost, rate of recruitment and conversion rate in each group was calculated. Performance metrics of social media campaigns (reach, impressions, clicks, inquiries, enrolments) were recorded. Linear regression was used to explore the association between metrics and dollars spent per campaign. Results In total, n = 481 inquiries were received: n = 51 (11%) via offline methods and n = 430 (89%) via social media. Enrolees (n = 60 total) included n = 24 (40%) and n = 36 (60%) via offline and social media methods, respectively. Gestational weeks upon inquiry (n = 251; mean ± SD) were not different among groups (offline: 13.3 ± 4.7; social media: 13.2 ± 5.6). Direct cost per enrolee was CA$13 and CA$19 via offline and social media methods, respectively (however, this does not include cost of labour). The rate of recruitment was approximately six times faster via social media. However, the conversion rate was higher via offline methods than social media (47% vs. 8%). The amount spent per campaign was significantly associated with improved clicks and inquiries, but not enrolments. Conclusions Social media was more efficient and effective than offline methods. We gained numerous insights for optimization of social media campaigns (dollars spent, attribution setting, photo testing, automatic optimization) to increase clicks and inquiries, however, this does not necessarily increase enrolments, which was more dependent on study-specific factors (e.g. time of year, study design).

Little is known about the ability of the recently released Brazilian gestational weight gain (GWG) charts to predict the occurrence of adverse birth outcomes.We compared the new Brazilian weight gain charts with 3 international charts and determined their ability to predict the occurrence of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) births in Brazilian women.A subsample of 6888 adult women (43,931 weight measurements) with singleton pregnancies from a nationwide, hospital-based cohort study conducted in 2011-2012 was analyzed. Selected percentiles from Brazilian GWG charts were compared with those from American, International Fetal and Newborn Growth Consortium for the 21st Century study, and Lifecycle consortium charts. Sensitivity, specificity, and AUROC values for SGA and LGA births were estimated with 95% CIs using the classification of GWG below or above selected percentiles of each chart.The weight gain corresponding to a given percentile varied among the charts, especially for women with pre-pregnancy overweight and obesity. The proportions of women with GWG classified below or above selected percentiles were closest to the expected values for all pre-pregnancy BMI categories in the Brazilian and Lifecycle charts. At the 10th percentile, the highest sensitivity for SGA births was observed for the American charts at midpregnancy (36.8%) and the highest specificity was observed using the Brazilian charts in the first trimester (93.4%). At the 90th percentile, the highest sensitivity for LGA births occurred in midpregnancy for the Lifecycle charts (26.8%) and the highest specificity occurred in the American charts using total GWG (97.1%). All the AUROCs were under 0.5 for SGA births and ranged from 0.55 (first trimester) to 0.62 (total GWG) for LGA births.The charts differ in GWG trajectories, especially for women with overweight and obesity. The 4 charts had low predictive ability of SGA and LGA births and should not be considered as isolated screening tools for those outcomes.