Do current pregnancy weight gain guidelines balance risks of adverse maternal and child health in a United States cohort?

BACKGROUND: The Institute of Medicine pregnancy weight gain guidelines were developed without evidence linking high weight gain to maternal cardiometabolic disease and child obesity. The upper limit of current recommendations may be too high for the health of the pregnant individual and child. OBJECTIVES: The aim of this study was to identify the range of pregnancy weight gain for pregnancies within a normal body mass index (BMI) range that balances the risks of high and low weight gain by simultaneously considering 10 different health conditions. METHODS: We used data from an United States prospective cohort study of nulliparae followed until 2 to 7 y postpartum (N = 2344 participants with a normal BMI). Pregnancy weight gain z-score was the main exposure. The outcome was a composite consisting of the occurrence of ≥1 of 10 adverse health conditions that were weighted for their seriousness. We used multivariable Poisson regression to relate weight gain z-scores with the weighted composite outcome. RESULTS: The lowest risk of the composite outcome was at a pregnancy weight gain z-score of -0.6 SD (standard deviation) (equivalent to 13.1 kg at 40 wk). The weight gain ranges associated with no more than 5%, 10%, and 20% increase in risks were -1.0 to -0.2 SD (11.2-15.3 kg), -1.4 to 0 SD (9.4-16.4 kg), and -2.0 to 0.4 SD (7.0-18.9 kg). When we used a lower threshold to define postpartum weight increase in the composite outcome (>5 kg compared with >10 kg), the ranges were 1.6 to -0.7 SD (8.9-12.6 kg), -2.2 to -0.3 SD (6.3-14.7 kg), and ≤0.2 SD (≤17.6 kg). Compared with the ranges of the current weight gain guidelines (-0.9 to -0.1 SD, 11.5-16 kg), the lower limits from our data tended to be lower while upper limits were similar or lower. CONCLUSIONS: If replicated, our results suggest that policy makers should revisit the recommended pregnancy weight gain range for individuals within a normal BMI range.

Periconceptional Dietary Patterns and Adverse Pregnancy and Birth Outcomes.

BACKGROUND: The periconceptional period is a critical window for the origins of adverse pregnancy and birth outcomes, yet little is known about the dietary patterns that promote perinatal health. OBJECTIVE: We used machine learning methods to determine the effect of periconceptional dietary patterns on risk of preeclampsia, gestational diabetes, preterm birth, small-for-gestational-age (SGA) birth, and a composite of these outcomes. METHODS: We used data from 8259 participants in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (8 US medical centers, 2010‒2013). Usual daily periconceptional intake of 82 food groups was estimated from a food frequency questionnaire. We used k-means clustering with a Euclidean distance metric to identify dietary patterns. We estimated the effect of dietary patterns on each perinatal outcome using targeted maximum likelihood estimation and an ensemble of machine learning algorithms, adjusting for confounders including health behaviors and psychological, neighborhood, and sociodemographic factors. RESULTS: The 4 dietary patterns that emerged from our data were identified as "Sandwiches and snacks" (34% of the sample); "High fat, sugar, and sodium" (29%); "Beverages, refined grains, and mixed dishes" (21%); and "High fruits, vegetables, whole grains, and plant proteins" (16%). One-quarter of pregnancies had preeclampsia (8% incidence), gestational diabetes (5%), preterm birth (8%), or SGA birth (8%). Compared with the "High fat, sugar, and sodium" pattern, there were 3.3 to 4.3 fewer cases of the composite adverse outcome per 100 pregnancies among participants following the "Beverages, refined grains and mixed dishes" pattern (risk difference -0.043; 95% confidence interval -0.078, -0.009), "High fruits, vegetables, whole grains and plant proteins" pattern (-0.041; 95% confidence interval -0.078, -0.004), and "Sandwiches and snacks" pattern (-0.033; 95% confidence interval -0.065, -0.002). CONCLUSIONS: Our results highlight that there are a variety of periconceptional dietary patterns that are associated with perinatal health and reinforce the negative health implications of diets high in fat, sugars, and sodium.

Early Gestational Weight Gain and the Risk of Preeclampsia in Dichorionic Twin Pregnancies.

OBJECTIVE: The purpose of our study was to evaluate the body mass index (BMI)-specific association between early gestational weight gain (GWG) in dichorionic twin pregnancies and the risk of preeclampsia. STUDY DESIGN: We conducted a retrospective cohort study of all dichorionic twin pregnancies from 1998 to 2013. Data were obtained from a perinatal database and chart abstraction. Prepregnancy BMI was categorized as normal (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (≥30 kg/m2). Early GWG was defined as the last measured weight from 160/7 to 196/7weeks' gestation minus prepregnancy weight. GWG was standardized for gestational duration using BMI-specific z-score charts for dichorionic pregnancies. Preeclampsia was diagnosed using American College of Obstetricians and Gynecologists criteria and identified with International Classification of Diseases-9 coding. Early GWG z-score was modeled as a three-level categorical variable (≤ - 1 standard deviation [SD], 0, 3 +1 SD), where -1 to +1 was the referent group. We estimated risk differences and 95% confidence intervals (CIs) via marginal standardization. RESULTS: We included 1,693 dichorionic twin pregnancies in the cohort. In adjusted analysis, the incidence of preeclampsia increased with increasing early GWG among women with normal BMI. Women with normal BMI and a GWG z-score < - 1 (equivalent to 2.6 kg by 20 weeks) had 2.5 fewer cases of preeclampsia per 100 births (95% CI: -4.7 to - 0.3) compared with the referent; those with GWG z-score > +1 (equivalent to gaining 9.8 kg by 20 weeks) had 2.8 more cases of preeclampsia per 100 (95 % CI: 0.1-5.5) compared with the referent. In adjusted analyses, early GWG had minimal impact on the risk of preeclampsia in women with overweight or obesity. CONCLUSION: GWG of 2.6 kg or less by 20 weeks was associated with a decreased risk of preeclampsia among women pregnant with dichorionic twins and normal prepregnancy BMI. Current GWG guidelines focus on optimizing fetal weight and gestational length. Our findings demonstrate the importance of considering other outcomes when making GWG recommendations for twin pregnancy. KEY POINTS: · Early GWG decreased with increasing BMI category.. · Among women with normal weight, as early GWG increased so did the risk of preeclampsia.. · There was no association between early GWG and preeclampsia among women with overweight or obesity..

Gestational weight gain in triplet pregnancies in the United States.

BACKGROUND: The Institute of Medicine has published national recommendations for optimal pregnancy weight gain ranges for singletons and twins but not for higher-order multiples. A common clinical resource suggests weight gain targets for triplet pregnancies, but they are based on a single, small study conducted over 20 years ago. OBJECTIVE: We sought to describe contemporary maternal weight gain patterns in triplet gestations in the United States, the weight gain patterns associated with good neonatal outcomes, and how these patterns compare with those of healthy twin pregnancies. STUDY DESIGN: We used data from 7705 triplet pregnancies drawn from the United States live birth and fetal death files (2012‒2018). We calculated total pregnancy weight gain as weight at delivery minus the prepregnancy weight. A good neonatal outcome was defined as delivery at ≥32 weeks' gestation of 3 liveborn infants weighing ≥1500 g with 5-minute Apgar scores of ≥3. We described the weight gain patterns of triplet pregnancies with good neonatal outcomes by calculating week-specific percentiles of the total weight gain distribution for deliveries at 32 to 37 weeks' gestation. For comparative purposes, we plotted these values against the percentiles of a previously published weight gain chart for monitoring and evaluating twin pregnancies from a referent cohort. RESULTS: Most participants were over weight (26%) or obese (30%), and 42% were normal weight or underweight. The 50th percentile (25th-75th) of total weight gain in triplet pregnancies was 17 (11-23) kg. As the body mass index category increased, the total weight gain declined: underweight or normal weight, median 19 (14-25) kg; overweight, 17 (12-23) kg; obese, 14 (7.7-20) kg. Approximately 46% of triplet pregnancies had a good neonatal outcome (n=3562). For underweight or normal weight triplet pregnancies with good neonatal outcomes, the 50th percentiles of weight gain at 32 weeks' and 36 weeks' gestation were 12.3 kg and 22.7 kg, respectively. The 10th and 90th percentiles were 12.3 kg and 32.7 kg, respectively, at 32 weeks, and 15.0 kg and 34.1 kg, respectively, at 36 weeks. Triplet pregnancies with prepregnancy overweight or obesity and a good neonatal outcome had lower weight gains. Compared with the reference values for pregnancy weight gain from a twin-specific weight gain chart, the median total weight gain in triplet pregnancies with good neonatal outcomes was approximately 3 to 5 kg more than twins, regardless of body mass index. CONCLUSION: Our study fills an important gap in understanding how much weight gain can be expected among triplet pregnancies by body mass index category. These descriptive data are a necessary first step to inform science-based triplet gestational weight gain guidelines. Additional research is needed to determine whether monitoring triplet pregnancy weight gain is useful for promoting healthy outcomes for pregnant individuals and children and what targets should be used to optimize maternal and neonatal health.

Use of a Doubly Robust Machine-Learning-Based Approach to Evaluate Body Mass Index as a Modifier of the Association Between Fruit and Vegetable Intake and Preeclampsia.

The Dietary Guidelines for Americans rely on summaries of the effect of dietary pattern on disease risk, independent of other population characteristics. We explored the modifying effect of prepregnancy body mass index (BMI; weight (kg)/height (m)2) on the relationship between fruit and vegetable density (cup-equivalents/1,000 kcal) and preeclampsia using data from a pregnancy cohort study conducted at 8 US medical centers (n = 9,412; 2010-2013). Usual daily periconceptional intake of total fruits and total vegetables was estimated from a food frequency questionnaire. We quantified the effects of diets with a high density of fruits (≥1.2 cups/1,000 kcal/day vs. <1.2 cups/1,000 kcal/day) and vegetables (≥1.3 cups/1,000 kcal/day vs. <1.3 cups/1,000 kcal/day) on preeclampsia risk, conditional on BMI, using a doubly robust estimator implemented in 2 stages. We found that the protective association of higher fruit density declined approximately linearly from a BMI of 20 to a BMI of 32, by 0.25 cases per 100 women per each BMI unit, and then flattened. The protective association of higher vegetable density strengthened in a linear fashion, by 0.3 cases per 100 women for every unit increase in BMI, up to a BMI of 30, where it plateaued. Dietary patterns with a high periconceptional density of fruits and vegetables appear more protective against preeclampsia for women with higher BMI than for leaner women.

The impact of panel composition and topic on stakeholder perspectives: Generating hypotheses from online maternal and child health modified-Delphi panels.

INTRODUCTION: Multistakeholder engagement is crucial for conducting health services research. Delphi-based methodologies combining iterative rounds of questions with feedback on and discussion of group results are a well-documented approach to multistakeholder engagement. This study develops hypotheses about the impact of panel composition and topic on the propensity and meaningfulness of response changes in multistakeholder modified-Delphi panels. METHODS: We conducted three online modified-Delphi (OMD) multistakeholder panels using the same protocol. We assigned 60 maternal and child health professionals to a homogeneous (professionals only) panel, 60 pregnant or postpartum women (patients) to a homogeneous panel, and 30 professionals and 30 patients to a mixed panel. In Round 1, participants rated the seriousness of 11 maternal and child health outcomes using a 0-100 scale and explained their ratings. In Round 2, participants saw their own and their panel's Round 1 results and discussed them using asynchronous, anonymous discussion boards moderated by the study investigators. In Round 3, participants revised their original ratings. Our outcome measures included binary indicators of response changes to ratings of the low, medium and high severity maternal and child health outcomes and their meaningfulness, measured by a change of 10 or more points. RESULTS: Participants changed 818 of 1491 (55%) of responses; the majority of response changes were meaningful. Patterns of response changes were different for patients and professionals and for different levels of outcome seriousness. Using study results and the literature, we developed three hypotheses. First, OMD participants, regardless of their stakeholder group, are more likely to change their responses on preference-sensitive topics where there is a range of viable alternatives or perspectives. Second, patients are more likely to change their responses and to do so meaningfully in mixed panels, whereas professionals are more likely to do so in homogeneous panels. Third, the association between panel composition and response change varies according to the topic (e.g., the level of outcome seriousness). CONCLUSIONS: Results of our work not only helped generate empirically derived hypotheses to be tested in future research but also offer practical recommendations for designing multistakeholder OMD panels. PATIENT OR PUBLIC CONTRIBUTION: Pregnant or postpartum women were involved in this study.

Can Ensemble Machine Learning Improve the Accuracy of Severe Maternal Morbidity Screening in a Perinatal Database?

BACKGROUND: Severe maternal morbidity (SMM) is an important maternal health indicator, but existing tools to identify SMM have substantial limitations. Our objective was to retrospectively identify true SMM status using ensemble machine learning in a hospital database and to compare machine learning algorithm performance with existing tools for SMM identification. METHODS: We screened all deliveries occurring at Magee-Womens Hospital, Pittsburgh, PA (2010-2011 and 2013-2017) using the Centers for Disease Control and Prevention list of diagnoses and procedures for SMM, intensive care unit admission, and/or prolonged postpartum length of stay. We performed a detailed medical record review to confirm case status. We trained ensemble machine learning (SuperLearner) algorithms, which "stack" predictions from multiple algorithms to obtain optimal predictions, on 171 SMM cases and 506 non-cases from 2010 to 2011, then evaluated the performance of these algorithms on 160 SMM cases and 337 non-cases from 2013 to 2017. RESULTS: Some SuperLearner algorithms performed better than existing screening criteria in terms of positive predictive value (0.77 vs. 0.64, respectively) and balanced accuracy (0.99 vs. 0.86, respectively). However, they did not perform as well as the screening criteria in terms of true-positive detection rate (0.008 vs. 0.32, respectively) and performed similarly in terms of negative predictive value. The most important predictor variables were intensive care unit admission and prolonged postpartum length of stay. CONCLUSIONS: Ensemble machine learning did not globally improve the ascertainment of true SMM cases. Our results suggest that accurate identification of SMM likely will remain a challenge in the absence of a universal definition of SMM or national obstetric surveillance systems.

Pregnancy weight gain in twin gestations and maternal and child health outcomes at 5 years.

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.

Rating the seriousness of maternal and child health outcomes linked with pregnancy weight gain.

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.

Excessive gestational weight gain is associated with severe maternal morbidity.

PURPOSE: We determined the association between gestational weight gain and severe maternal morbidity. METHODS: We used data on 84,241 delivery hospitalizations at Magee-Womens Hospital, Pittsburgh, PA (2003-2012). Total gestational weight gain (kilogram) was converted to gestational age-standardized z-scores. We defined severe maternal morbidity as having ≥1 of the 21 Centers for Disease Control diagnosis or procedure codes for severe maternal morbidity identification, intensive care unit admission, or extended postpartum stay. We used multivariable logistic regression to determine the association between weight gain and severe maternal morbidity after confounder adjustment. RESULTS: High gestational weight gain z-scores were associated with an increased risk of severe maternal morbidity. Compared with z-score 0 SD (equivalent to 16 kg at 40 weeks in a normal-weight woman), risk differences (95% confidence intervals) for z-scores -2 SD (7 kg), -1 SD (11 kg), +1 SD (23 kg), and +2 SD (31 kg) were 1.5 (-0.71, 3.7), 0.056 (-0.81, 0.93), 3.4 (1.7, 5.0), and 8.6 (4.0, 13) per 1000 deliveries. The results did not vary by gestational age at delivery or prepregnancy body mass index. CONCLUSIONS: The increased risk of severe maternal morbidity with high pregnancy weight gain may allow scientists to understand and prevent this serious condition.

Gestational Weight Gain and Adverse Birth Outcomes in Twin Pregnancies.

OBJECTIVE: To evaluate the association between gestational weight gain in twin pregnancies and small-for-gestational-age (SGA) and large-for-gestational-age (LGA) birth, preterm birth before 32 weeks of gestation, cesarean delivery, and infant death within each prepregnancy body mass index (BMI) category. METHODS: Data in this population-based study came from Pennsylvania-linked infant birth and death records (2003-2013). We studied 54,836 twins born alive before 39 weeks of gestation. Total pregnancy weight gain (kg) was converted to gestational age-standardized z scores. Multivariable modified Poisson regression models stratified by prepregnancy BMI were used to estimate associations between z scores and outcomes. A probabilistic bias analysis, informed by an internal validation study, evaluated the effect of BMI and weight gain misclassification. RESULTS: Gestational weight gain z score was negatively associated with SGA and positively associated with LGA and cesarean delivery in all BMI groups. The relation between weight gain and preterm birth was U-shaped in nonobese women. An increased risk of infant death was observed for very low weight gain among normal-weight women and for high weight gain among women without obesity. Most excess risks of these outcomes were observed at weight gains at 37 weeks of gestation that are equivalent to less than 14 kg or more than 27 kg in underweight or normal-weight women, less than 11 kg or more than 28 kg in overweight women, and less than 6.4 kg or more than 26 kg in women with obesity. The bias analysis supported the validity of the conventional analysis. CONCLUSION: Very low or very high weight gains were associated with the adverse outcomes we studied. If the associations we observed are even partially reflective of causality, targeted modification of pregnancy weight gain in women carrying twins might improve pregnancy outcomes.

Early-pregnancy weight gain and the risk of preeclampsia: A case-cohort study.

OBJECTIVE: To investigate the association between early-pregnancy weight gain and risk of preeclampsia to inform pregnancy weight gain recommendations. STUDY DESIGN: We performed a case-cohort study using a hospital database including 80,812 singleton deliveries from Magee-Womens Hospital, Pittsburgh, Pennsylvania (1998-2011). In each of 6 prepregnancy body mass index (BMI) groups, we abstracted serial antenatal weight measurements from the records of up to 339 preeclampsia cases and 1254 randomly selected pregnancies. Early gestational weight gain (16-19 weeks' gestation) was standardized for gestational duration using BMI-specific z-score charts. Multivariable log-binomial regression was used to assess the association between weight gain z-score and risk of preeclampsia. We determined the impact of preeclampsia misclassification using probabilistic bias analysis. MAIN OUTCOME MEASURE: Risk of preeclampsia. RESULTS: For normal weight women, there was a steady increase in preeclampsia risk with increasing early gestational weight gain z-score. For example, compared with a weight gain of 1.2 kg (z-score = -1 SD), a 7.2-kg weight gain (z-score = +1 SD) at 16 weeks was associated with 1.3 (0.50, 2.2) excess preeclampsia cases per 100 deliveries. Weight loss at 16-19 weeks among grade 2 or 3 obese women was associated with a reduced risk of preeclampsia. Associations were null among overweight and grade 1 obese women. The bias analysis supported the validity of the conventional analysis. CONCLUSIONS: Early-pregnancy weight gain may be associated with preeclampsia in some BMI groups. Future revisions of pregnancy weight gain recommendations should account for preeclampsia risks from this and additional studies.

Weight resilience and fruit and vegetable intake among African-American women in an obesogenic environment.

OBJECTIVE: To investigate relationships between weight resilience (maintaining a normal weight in a food desert environment) and fruit and vegetable (F&V) intake, attitudes and barriers. DESIGN: Cross-sectional, in-person surveys collected May-December 2011, including self-reported data on F&V-related psychosocial factors, attitudes and barriers. Two 24 h dietary recalls were completed; weight and height were measured. Multivariable regression models estimated prevalence ratios (95 % CI). SETTING: Two low-income, predominantly African-American food deserts in Pittsburgh, Pennsylvania, USA. SUBJECTS: Women aged 18-49 years (n 279) who were the primary food shopper in a household randomly selected for a parent study. RESULTS: Fifteen per cent were weight resilient, 30 % were overweight and 55 % were obese. Overall, 25 % reported eating ≥5 F&V servings/d. After adjustment for age, education, parity, employment, living alone, physical activity, per capita income and mean daily energy intake, women eating ≥5 F&V servings/d were 94 % more likely to be weight resilient compared with those eating <5 servings/d (1·94; 1·10, 3·43). Across BMI groups, self-efficacy regarding F&V consumption was high and few F&V barriers were reported. The most frequently reported barrier was concern about the cost of F&V (36 %). Of the attitudinal F&V-related factors, only concern about wasting food when serving F&V was associated with weight resilience in adjusted models (0·29; 0·09, 0·94). In a model predicting consuming ≥5 F&V servings/d, driving one's own car to the store was the only attitudinal F&V-related factor associated with consumption (1·50; 1·00, 2·24). CONCLUSIONS: In this population, weight resilience may be encouraged by improving access to affordable and convenient F&V options and providing education on ways to make them palatable to the entire household, rather than by shifting women's F&V perceptions, which are already positive.

Low Gestational Weight Gain and Risk of Adverse Perinatal Outcomes in Obese and Severely Obese Women.

BACKGROUND: Our objective was to estimate associations between gestational weight gain z scores and preterm birth, neonatal intensive care unit admission, large- and small-for-gestational age birth, and cesarean delivery among grades 1, 2, and 3 obese women. METHODS: We included singleton infants born in Pennsylvania (2003-2011) to grade 1 (body mass index 30-34.9 kg/m, n = 148,335), grade 2 (35-39.9 kg/m, n = 72,032), or grade 3 (≥40 kg/m, n = 47,494) obese mothers. Total pregnancy weight gain (kg) was converted to gestational age-standardized z scores. Multivariable Poisson regression models stratified by obesity grade were used to estimate associations between z scores and outcomes. A probabilistic bias analysis, informed by an internal validation study, evaluated the impact of body mass index and weight gain misclassification. RESULTS: Risks of adverse outcomes did not substantially vary within the range of z scores equivalent to 40-week weight gains of -4.3 to 9 kg for grade 1 obese, -8.2 to 5.6 kg for grade 2 obese, and -12 to -2.3 kg for grade 3 obese women. As gestational weight gain increased beyond these z score ranges, there were slight declines in risk of small-for-gestational age birth but rapid rises in cesarean delivery and large-for-gestational age birth. Risks of preterm birth and neonatal intensive care unit admission were weakly associated with weight gain. The bias analysis supported the validity of the conventional analysis. CONCLUSIONS: Gestational weight gain below national recommendations for obese mothers (5-9 kg) may not be adversely associated with fetal growth, gestational age at delivery, or mode of delivery.

Maternal obesity and gestational weight gain are risk factors for infant death.

OBJECTIVE: Assessment of the joint and independent relationships of gestational weight gain and prepregnancy body mass index (BMI) on risk of infant mortality was performed. METHODS: This study used Pennsylvania linked birth-infant death records (2003-2011) from infants without anomalies born to mothers with prepregnancy BMI categorized as underweight (n = 58,973), normal weight (n = 610,118), overweight (n = 296,630), grade 1 obesity (n = 147,608), grade 2 obesity (n = 71,740), and grade 3 obesity (n = 47,277). Multivariable logistic regression models stratified by BMI category were used to estimate dose-response associations between z scores of gestational weight gain and infant death after confounder adjustment. RESULTS: Infant mortality risk was lowest among normal-weight women and increased with rising BMI category. For all BMI groups except for grade 3 obesity, there were U-shaped associations between gestational weight gain and risk of infant death. Weight loss and very low weight gain among women with grades 1 and 2 obesity were associated with high risks of infant mortality. However, even when gestational weight gain in women with obesity was optimized, the predicted risk of infant death remained higher than that of normal-weight women. CONCLUSIONS: Interventions aimed at substantially reducing preconception weight among women with obesity and avoiding very low or very high gestational weight gain may reduce risk of infant death.

Same-day intrauterine device placement is rarely complicated by pelvic infection.

PURPOSE: To compare rates of pelvic inflammatory disease (PID) among women who did and did not receive an intrauterine device (IUD) the day they sought emergency contraception (EC) or pregnancy testing. METHODS: Women, 15 to 45 years of age, who sought EC or pregnancy testing from an urban family planning clinic completed surveys at the time of their clinic visit (August 22, 2011, to May 30, 2013) and 3 months after their clinic visit. The surveys assessed contraceptive use and symptoms, testing, and treatment for sexually transmitted infections (STI) and PID. We reviewed the medical records of participants who reported IUD placement within 3 months of enrollment and abstracted de-identified electronic medical record (EMR) data on all women who sought EC or pregnancy testing from the study clinic during the study period. FINDINGS: During the study period, 1,060 women visited the study clinic; 272 completed both enrollment and follow-up surveys. Among survey completers with same-day IUD placement, PID in the 3 months after enrollment was not more common (1/28 [3.6%]; 95% CI, 0%-10.4%) than among women who did not have a same-day IUD placed (11/225 [4.9%]; 95% CI, 2.7%-8.6%; p = .71). Chart review and EMR data similarly showed that rates of PID within 3 months of seeking EC or pregnancy testing were low whether women opted for same-day or delayed IUD placement. CONCLUSIONS: Same-day IUD placement was not associated with higher rates of PID. Concern for asymptomatic STI should not delay IUD placement, and efforts to increase the uptake of this highly effective reversible contraception should not be limited to populations at low risk of STI.

Comparison of gestational weight gain z-scores and traditional weight gain measures in relation to perinatal outcomes.

BACKGROUND: Conventional measures of gestational weight gain (GWG) are correlated with pregnancy duration, and may induce bias to studies of GWG and perinatal outcomes. A maternal weight-gain-for-gestational-age z-score chart is a new tool that allows total GWG to be classified as a standardised z-score that is independent of gestational duration. Our objective was to compare associations with perinatal outcomes when GWG was assessed using gestational age-standardised z-scores and conventional GWG measures. METHODS: We studied normal-weight (n=522 120) and overweight (n=237 923) women who delivered liveborn, singleton infants in Pennsylvania, 2003-11. GWG was expressed using gestational age-standardised z-scores and three traditional measures: total GWG (kg), rate of GWG (kg per week of gestation), and the GWG adequacy ratio (observed GWG/GWG recommended by the Institute of Medicine). Log-binomial regression models were used to assess associations between GWG and preterm birth, and small- and large-for-gestational-age births, while adjusting for race/ethnicity, education, smoking, and other confounders. RESULTS: The association between GWG z-score and preterm birth was approximately U-shaped. The risk of preterm birth associated with weight gain <10th percentile of each measure was substantially overestimated when GWG was classified using total kilogram and was moderately overestimated using rate of GWG or GWG adequacy ratio. All GWG measures had similar associations with small- or large-for-gestational-age birth. CONCLUSIONS: Our findings suggest that studies of gestational age-dependent outcomes misspecify associations if total GWG, rate of GWG, or GWG adequacy ratio are used. The potential for gestational age-related bias can be eliminated by using z-score charts to classify total GWG.

Routine counseling about intrauterine contraception for women seeking emergency contraception.

OBJECTIVE: To compare contraceptive knowledge and use among women seeking emergency contraception (EC) before and after an inner-city clinic began providing structured counseling and offering same-day intrauterine device (IUD) or implant placement to all women seeking EC. STUDY DESIGN: For 8 months before and 21 months after this change in clinic policy, women aged 15-45 who wanted to avoid pregnancy for at least 6 months were asked to complete surveys immediately, 3 and 12 months after their clinic visit. In addition, we abstracted electronic medical record (EMR) data on all women who sought EC (n=328) during this period. We used chi-squared tests to assess pre/post differences in survey and EMR data. RESULTS: Surveys were completed by 186 women. After the clinic began offering structured counseling, more women had accurate knowledge of the effectiveness of IUDs, immediately and 3 months after their clinic visit. In addition, more women initiated IUD or implant use (survey: 40% vs. 17% preintervention, p=0.04; EMR: 22% vs. 10% preintervention, p=0.01), and fewer had no contraceptive use (survey: 3% vs. 17% preintervention, p<0.01; EMR: 32% vs. 68%, p<0.01) in the 3 months after seeking EC. EMR data indicate that when same-day placement was offered, 11.0% of women received a same-day IUD. Of those who received a same-day IUD, 88% (23/26) reported IUD use at 3-months and 80% (12/15) at 12 months. CONCLUSIONS: Routine provision of structured counseling with the offer of same-day IUD placement increases knowledge and use of IUDs 3 months after women seek EC. IMPLICATIONS: Women seeking EC from family planning clinics should be offered counseling about highly effective reversible contraceptives with the option of same-day contraceptive placement.

Validity of birth certificate-derived maternal weight data.

BACKGROUND: Studies using vital records-based maternal weight data have become more common, but the validity of these data is uncertain. METHODS: We evaluated the accuracy of prepregnancy body mass index (BMI) and gestational weight gain (GWG) reported on birth certificates using medical record data in 1204 births at a teaching hospital in Pennsylvania from 2003 to 2010. Deliveries at this hospital were representative of births statewide with respect to BMI, GWG, race/ethnicity, and preterm birth. Forty-eight strata were created by simultaneous stratification on prepregnancy BMI (underweight, normal weight/overweight, obese class 1, obese classes 2 and 3), GWG (<20th, 20-80th, >80th percentile), race/ethnicity (non-Hispanic white, non-Hispanic black), and gestational age (term, preterm). RESULTS: The agreement of birth certificate-derived prepregnancy BMI category with medical record BMI category was highest in the normal weight/overweight and obese class 2 and 3 groups. Agreement varied from 52% to 100% across racial/ethnic and gestational age strata. GWG category from the birth registry agreed with medical records for 41-83% of deliveries, and agreement tended to be the poorest for very low and very high GWG. The misclassification of GWG was driven by errors in reported prepregnancy weight rather than maternal weight at delivery, and its magnitude depended on prepregnancy BMI category and gestational age at delivery. CONCLUSIONS: Maternal weight data, particularly at the extremes, are poorly reported on birth certificates. Investigators should devote resources to well-designed validation studies, the results of which can be used to adjust for measurement errors by bias analysis.