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Background Global climate change has led to an increase in the prevalence and severity of wildfires. Pollutants released into air, soil and groundwater from wildfires may impact embryo development leading to gastroschisis. Objective The objective of this study was to determine the association between wildfire exposure before and during pregnancy and the risk of foetal gastroschisis development. Methods This was a retrospective cohort study using The California Office of Statewide Health Planning and Development Linked Birth File linked to The California Department of Forestry and Fire Protection data between 2007 and 2010. Pregnancies complicated by foetal gastroschisis were identified by neonatal hospital discharge ICD-9 code. Pregnancies were considered exposed to wildfire if the mother's primary residence zip code was within 15 miles to the closest edge of a wildfire. The exposure was further stratified by trimester or if exposed within 30 days prior to pregnancy. Multivariable log-binomial regression analyses were performed to estimate the association between wildfire exposure in each pregnancy epoch and foetal gastroschisis. Results Between 2007 and 2010, 844,348 (40%) births were exposed to wildfire in California. Compared with births without wildfire exposure, those with first-trimester exposure were associated with higher rates of gastroschisis, 7.8 vs. 5.7 per 10,000 births (adjusted relative risk [aRR] 1.28, 95% confidence interval [CI] 1.07, 1.54). Furthermore, those with prepregnancy wildfire exposure were also found to have higher rates of gastroschisis, 12.5 vs. 5.7 per 10,000 births, (aRR 2.17, 95% CI 1.42, 3.52). In contrast, second- and third-trimester wildfire exposures were not associated with foetal gastroschisis. Conclusions Wildfire exposure within 30 days before pregnancy was associated with more than two times higher risk of foetal gastroschisis, whereas a 28% higher risk was demonstrated if exposure was in the first trimester.

Objective: Obesity and pregestational diabetes (PGDM) may interact to further increase the risk of stillbirth than either risk factors independently. The objective of this study was to determine th...

BackgroundPatients with placenta accreta spectrum (PAS) disorders often suffer massive hemorrhage during cesarean hysterectomies (CHyst). A novel strategy to decrease blood loss and minimize perioperative morbidity associated with PAS is utilization of ER-REBOA Catheter intraoperatively. In this study, we explore the use of ER-REBOA Catheter during CHyst with the goal of minimizing perioperative morbidity and packed red blood cell (PRBC) transfusions.MethodsWe conducted a retrospective case–control study at a regional referral center of consecutive patients with PAS undergoing CHyst. The primary outcomes were PRBC transfusions of ≥4 units. Secondary outcomes included surgical intensive care unit admissions, postoperative length of stay (LOS), postoperative ileus, and vascular complication rate. We also explored utilization of manual palpation and omission of precesarean fluoroscopy for resuscitative endovascular balloon occlusion of the aorta (REBOA) placement verification in distal aortic zone 3.Results90 patients were included in the study. REBOA and non-REBOA cases were similar in clinicodemographic characteristics. 17.7% of REBOA cases received ≥4 units of PRBC compared with 49.3% of non-REBOA cases (p=0.03). Zero REBOA patients developed postoperative ileus, whereas 18 (25%) non-REBOA patients did (p=0.02). LOS was reduced in the REBOA group. Postplacement fluoroscopy was omitted in all REBOA cases. Two postoperative arterial thrombotic events (2 of 19, 11% of REBOA patients) were identified in the REBOA group, one requiring a thrombectomy (1 of 19, 5%).DiscussionDecrease in blood transfusions of ≥4 units of PRBC is demonstrated when ER-REBOA Catheter is placed in distal aortic zone 3 during CHyst performed for severe PAS disorders. The incidence of postoperative ileus and LOS are reduced in the ER-REBOA Catheter group. Placement and utilization of ER-REBOA Catheter during CHyst may be feasible without fluoroscopy when manual placement verification is performed by an experienced operator. Protocol modifications focusing on reducing thrombotic rate are ongoing.Level of evidenceIV.

Objective: To determine rates of maternal and perinatal outcomes after induction of labor (IOL) at 39 weeks compared with expectant management.Methods: Cohort study of low risk women delivered between 39-42 weeks from 2015 to 2018. We excluded births with fetal abnormalities, previous cesarean, multiple pregnancies or those with spontaneous onset of labor (SOL) or indicated delivery at 39 weeks. Data was abstracted from National Center for Health Statistics birth files. Relative risks (aRR) were estimated with multivariable log-binomial regression. Main Outcome Measures: Maternal outcomes: chorioamnionitis (Triple I), blood transfusion, neonatal intensive care unit (NICU) admission, uterine rupture, cesarean delivery and cesarean hysterectomy. Fetal and infant outcomes: fetal death, 5-minute Apgar ≤3, prolonged ventilation, seizures, ICU admission, and death within 28 days. Results: There were 15,900,956 births, with 8,540,063 after exclusions. The IOL group included 1,177,790 births excluding women with diabetes or hypertensive disease. There were 3,835,185 births after 39 weeks excluding women with diabetes or chronic hypertension. With IOL at 39 weeks the risk for blood transfusion (p-value < 0.01; aRR 0.78; 95% CI [0.75-0.82]), Triple I (p-value < 0.01; aRR 0.71; 95% CI [0.70-0.73]) and cesarean delivery (p-value Conclusions: Induction of labor at 39 weeks of gestation in a low risk cohort is associated a lower risk of cesarean delivery, transfusions and infection, as well as lower neonatal morbidity, without difference in fetal or neonatal death. This appears to be associated with increased risk for cesarean hysterectomy.

Objective: To determine maternal and neonatal morbidity associated with induction of labor at 39 weeks compared with expectant management through 42 weeks. Design: Cohort study Setting & Population: Low risk American women who delivered between 39 and 42 weeks in 2015 to 2017. Methods: Data was abstracted from the national vital statistics database. Multivariable log-binomial regression analysis was conducted to estimate the relative risk of morbidity. Main Outcome Measures: Maternal morbidity included Triple I, blood transfusion, ICU admission, uterine rupture, cesarean hysterectomy, and cesarean delivery. Neonatal morbidity included 5 minute Apgar ≤3, prolonged ventilation, seizures, NICU admission, and neonatal death. Results: A total of 1,885,694 women were included for analysis. Women undergoing induction of labor at 39 weeks were less likely to develop Triple I (p-value < 0.001; aRR 0.66; 95% CI [0.64-0.68]) and require a cesarean section (p-value

Purpose Maternal obesity has been consistently associated with offspring risk for ASD, as well as lipid metabolism derangements. However, few ASD studies have examined maternal lipids in conjunction with maternal prepregnancy body mass index (BMI). Methods This nested case-control study was based on the Boston Birth Cohort, a prospective cohort study of mother-child dyads recruited at the Boston Medical Center. Maternal blood samples were collected shortly after delivery and analyzed for total plasma cholesterol, HDL, and triglyceride (TG) concentrations. Low-density lipoprotein (LDL) was subsequently calculated by the Friedewald equation. Cases were identified using ASD diagnoses in children’s medical records. The odds of ASD were estimated with continuous lipid levels for a linear relationship, and we further explored the nonlinear relationship using the tertile of each lipid analyte with the highest tertile as the reference group. Logistic regression was used to estimate the risk of ASD adjusting for potential confounders. The analyses were performed separately for mothers with normal weight and overweight/obese based on maternal prepregnancy BMI. Results One standard deviation decrease in postpartum maternal LDL was associated with increased odds of ASD aOR 1.35 [1.04–1.75]. There was no association between postpartum maternal HDL and TG levels and ASD risk. Decreasing levels of LDL were not associated with ASD risk in normal-weight mothers (aOR 1.2 [0.83–1.75]), but the ASD risk was more pronounced in overweight and obese mothers (aOR 1.54 [1.03–2.27]). Follow-up analysis of nonlinear association models showed that, when compared to the highest tertile, lower maternal LDL concentrations were associated with approximately two times increased risk of ASD (first tertile: aOR 2.49 [1.27–4.87] and second tertile: aOR 2.79 [1.42–5.48]). A similar pattern was observed with overweight/obese mothers but not in normal-weight mothers. Conclusions Lower maternal postpartum plasma LDL concentration was associated with increased odds of ASD in offspring among children born to overweight and obese mothers. Our findings suggest that both maternal BMI and lipids should be considered in assessing their role in offspring ASD risk, and additional longitudinal studies are needed to better understand maternal lipid dynamics during pregnancy among normal-weight and overweight/obese mothers.

The optimal timing of induction for those undergoing a trial of labor after cesarean section has not been established. The little data which supports the consideration of induction at 39 weeks gestation excludes those with a history of prior cesarean section.To determine the risks and benefits of elective induction of labor (IOL) at 39 weeks compared with expectant management (EM) until 42 weeks in pregnancies complicated by one previous cesarean delivery.This is a retrospective cohort analysis of singleton non-anomalous pregnancies in the United States between January 2015 and December 2017. Data was provided by the CDC National Center for Health Statistics, Division of Vital Statistics. Analyses included only pregnancies with a history of one previous cesarean delivery (CD). Perinatal outcomes of pregnancies electively induced at 39 weeks (IOL) were compared to pregnancies that were induced, augmented or underwent spontaneous labor between 40 and 42 weeks (EM). Unlabored cesarean deliveries were excluded. Outcomes of interest included: cesarean delivery, intra-amniotic infection, blood transfusion, adult intensive care unit (ICU) admission, uterine rupture, hysterectomy, 5-minute Apgar scoreThere were 50,136 pregnancies included for analysis with 9,381 women in the IOL group. Compared with EM, IOL at 39 weeks decreased the risk of intra-amniotic infection (1.7% vs 3.0%,In pregnancies complicated by one previous cesarean delivery, elective induction of labor at 39 weeks reduced the risk of intra-amniotic infection, blood transfusion, and low 5-minute Apgar score while increased the risk of repeat cesarean delivery.

Background Pregestational diabetes mellitus is associated with a higher risk of adverse pregnancy outcomes. Based on the available data, it is unclear whether infants born preterm to mothers with pregestational diabetes mellitus are at a higher risk of adverse outcomes than other preterm infants. Objective This study aimed to quantify the neonatal complications associated with pregestational diabetes mellitus in infants born preterm. Study Design This was a retrospective cohort study of all nonanomalous singleton neonates born in Texas from 2006 to 2014. Analysis was limited to births between 24 and 36 weeks’ gestation and excluded multiple births, stillbirths, fetal congenital anomalies, neonates born to mothers with gestational diabetes mellitus, and neonates born to mothers with chronic hypertension. Results were stratified by pregestational diabetes mellitus status. Neonatal outcomes of interest included infant death, neonatal intensive care unit admission, low 5-minute Apgar scores, assisted ventilation of >6 hours, surfactant administration, and seizures. Multivariate logistic regression analysis was performed to estimate the association between pregestational diabetes mellitus and neonatal outcomes controlling for potential confounding variables. Results After predefined exclusions, 277,210 births were analyzed, 4164 of which were to mothers with pregestational diabetes mellitus. The comparison group consisted of mothers without pregestational diabetes mellitus. The preterm infant mortality rates between the pregestational diabetic and nondiabetic groups were similar. However, after adjusting for confounding variables, there was an increased risk of infant mortality for preterm neonates born to mothers with pregestational diabetes mellitus. In infants born preterm, pregestational diabetes mellitus was associated with an increased risk of infant death, low 5-minute Apgar score, prolonged assisted ventilation, surfactant requirement, and neonatal intensive care unit admission. Neonates born before 34 weeks’ gestation had an increased risk of assisted ventilation of >6 hours, neonatal intensive care unit admission, and seizure. Neonates born to mothers with pregestational diabetes mellitus in the late preterm period between 34 and 36 weeks’ gestation had an increased risk of low Apgar score at 5 minutes, assisted ventilation of >6 hours, surfactant use, and neonatal intensive care unit admission. Conclusion Pregestational diabetes mellitus is associated with a higher risk of adverse neonatal outcomes in infants born preterm.

This study aimed to evaluate the impact of obesity on early evaluation of fetal cardiac landmarks using a standardized examination method at the time of nuchal translucency scan.This was a cross-sectional study of an ongoing prospective cohort at high risk for congenital heart defects. We used a standardized examination protocol using 2-dimensional sonography with power Doppler in the evaluation of fetal cardiac landmarks consisting of 4-chamber view, outflow tract relationship, and transverse arches view. The study population was stratified based on maternal body mass index into nonobese (30 kg/mA total of 190 patients were evaluated. Of these, 48.4% (n = 92) were obese. The most common indication for fetal cardiac assessment was maternal pregestational diabetes mellitus (42.6%). Transvaginal sonography was utilized in one nonobese woman (1.4%) and 11 obese women (12%) (P = .002). The satisfactory evaluation of 4-chamber view, outflow tract relationship, transverse arches view, and all views were not significantly different between groups (P .05). The scan time was about 5 minutes longer in the obese group compared with nonobese group (P = .020).Obesity does not hamper early evaluation of fetal cardiac landmarks around the time of nuchal translucency scan. However, obese patients are more likely to require transvaginal examinations.

Objective: Down syndrome (DS) is associated with significant risk of perinatal mortality. We hypothesize that this association is primarily mediated through the effects of fetal growth restriction ...

BACKGROUND: Available data suggest that the obstetric population is particularly vulnerable to severe respiratory syndrome coronavirus 2 infection, with a variable clinical course leading to severe respiratory failure. However, established early warning scores designed to identify patients at risk of clinical deterioration were never validated in the obstetric population. OBJECTIVE: This retrospective cohort study sought to evaluate the initial clinical characteristics of pregnant patients diagnosed with severe acute respiratory syndrome coronavirus 2 infection and to develop a pregnancy-specific early warning score to identify patients at risk for clinical deterioration and requiring advanced respiratory support. STUDY DESIGN: This was a single center, retrospective cohort study of pregnant patients diagnosed with severe acute respiratory syndrome coronavirus 2 infection between April 2020 and December 2020. A total of 50 patients with severe acute respiratory syndrome coronavirus 2 infection between April 2020 and November 2020 were used to create the prediction model. Initial clinical characteristics identified at the time of diagnosis were compared between patients who required advanced respiratory support and those who were asymptomatic or had mild symptoms for those diagnosed during the period of April 2020 to November 2020. Risk factors associated with a requirement for advanced respiratory support were used to create the Obstetric Warning Score system. The Obstetric Warning Score system was then validated using 30 patients diagnosed with severe acute respiratory syndrome coronavirus 2 infection in December 2020. A receiver operating characteristic curve was generated to evaluate the test characteristics of the Obstetric Warning Score system compared with other scoring systems including the Early Warning Score, the National Early Warning Score 2, and the Maternal Early Warning Criteria. RESULTS: Women who required advanced respiratory support were more likely to present with dyspnea (100% vs 33.3%; P 100 beats per minute, temperature of >99.0°F, C-reactive protein level of >2.0 mg/dL, respiratory rate between 20 and 24 breaths per minute, complaints of dyspnea, and a positive chest x-ray. A respiratory rate of >24 breaths per minute was assigned 2 points. The area under the curve for the Obstetric Warning Score system was 0.97 compared with 0.72 for the Early Warning Score system, 0.92 for the National Early Warning Score 2 system, and 0.85 for the Maternal Early Warning Criteria system. An Obstetric Warning Score of ≥3 was predictive of a requirement for advanced respiratory support with a sensitivity of 100%, specificity 64%, and a positive predictive value of 36%. CONCLUSION: The Obstetric Warning Score system presents a validated method for providers to identify pregnant patients who are at risk for respiratory failure and a requirement for advanced respiratory support.

Obesity is associated with higher risks for intrapartum complications. Therefore, we sought to determine if trial of labor after cesarean section (TOLAC) will lead to higher maternal and neonatal complications compared to repeat cesarean section (RCD).This was a retrospective cohort analysis of singleton nonanomalous births between 37 and 42 weeks GA complicated by maternal obesity (body mass index (BMI) ≥ 30 kg/mThere were 538,264 pregnancies included. Compared with RCD, TOLAC was associated with an absolute increase in the following neonatal outcomes: low 5-min Apgar score (0.6%, p .001), neonatal intensive care unit (NICU) admission (0.8%, p .001), neonatal seizure (0.1 per 1000 births, p = .037), and neonatal death (0.2 per 1000 births, p = .028). Additionally, TOLAC was associated with an absolute increase in following maternal outcomes: blood transfusion (0.1%, p .001), uterine rupture (0.18%, p .001) and ICU admission (0.1%, p = .011).TOLAC among obesity pregnancies at term increases the risk of maternal and neonatal complications compared with RCD.

To describe the risk of adverse outcomes associated with uterine rupture in the setting of maternal obesity.This was a retrospective cohort analysis of singleton nonanomalous neonates born after uterine rupture between 34 and 42 weeks of gestation. We derived data from the U.S. Natality Database from 2011 to 2014. Maternal prepregnancy body mass index (BMI) was categorized according to the World Health Organization classification. The rates of neonatal and maternal complications were calculated for each BMI class. Multivariable logistic regression analysis was used to estimate the risks of these complications among obese pregnancies compared with normal-weight pregnancies.There were 3,942 cases of uterine rupture identified among 15,860,954 births (0.02%) between 2011 and 2014. Of these, 2,917 (74%) met inclusion criteria for analysis. There was an increased risk of low 5-minute Apgar score (22.9% compared with 15.9%; adjusted odds ratio [OR] 1.49 [1.19-1.87]), neonatal intensive care unit admission (31% compared with 24.6%; adjusted OR 1.51 [1.23-1.85]), and seizure (3.7% compared with 1.9%; adjusted OR 1.80 [1.05-3.10]) in obese compared with normal-weight pregnancies. The rate of prolonged assisted ventilation was 8.5% compared with 6.2% (P=.13), which, after adjustment for confounders, was a statistically significant difference (adjusted OR 1.47 [1.05-2.07]). The rate of neonatal death was similar (12.4 compared with 6.5/1,000 births; adjusted OR 2.03 [0.81-5.05]). The rates of various maternal complications were similar between groups.In the setting of uterine rupture, maternal obesity moderately increases the risks of low Apgar score, neonatal intensive care unit admission, prolonged ventilation, and seizure. Risk of maternal complications and the risk of neonatal death, however, are similar to risks in patients of normal BMI.

Maternal obesity has been associated with higher birth weight. Small for gestational age (SGA) neonates born to obese women may be associated with pathological growth with increased neonatal complications.This was a retrospective cohort study of all non-anomalous singleton neonates born in Texas from 2006-2011. Analyses were limited to births between 34 and 42 weeks gestation with birth weight ≤10th percentile. Results were stratified by maternal pre-pregnancy BMI class. The risk for stillbirth, neonatal death, neonatal intensive care unit (NICU) admission and five minute Apgar scores 7 were estimated for each obesity class and compared to the normal weight group. Multivariable logistic regression analyses were performed to control for potential confounding variables.The rate of stillbirth was 1.4/1000 births for normal weight women, and 2.9/1000 among obese women (p 0.001, aOR: 1.83 [1.43, 2.34]). The rate of neonatal deaths among normal weight women was 4.3/1000 births, whereas among obese women it was 4.7/1000 (p = 0.94, aOR: 1.10 [0.92, 1.30]). A dose-dependent relationship between maternal obesity and stillbirths was seen, but not for other neonatal outcomes.Among SGA neonates, maternal pre-pregnancy obesity was associated with increased risks for stillbirth, NICU admission and low Apgar scores but not neonatal death.

Historically, carrier screening for a small number of autosomal recessive disorders has been offered to targeted populations based on ethnicity and family history. These chosen disorders are associated with severe morbidity or mortality, have a well-established carrier frequency in the targeted population, and have an acceptably high detection rate to make screening efficient. With advancing genetic technology, expanded panels rapidly are being designed and offered to the panethnic general population. This article reviews current recommendations for ethnicity-specific carrier screening for common disorders as well as the limitations and counseling complexities associated with expanded panels.

Objective The purpose of this study is to determine the association between body mass index (BMI) and success of ECV. Methods This is a cross-sectional analysis of singleton live births in the USA from 2010 to 2014 using birth certificate data. Patients were assigned a BMI category according to standard WHO classification. Comparisons of success of ECV between the BMI categories were made using chi-square analysis with normal BMI as the reference group. Cochran-Armitage test was performed to look for a trend of decreasing success of ECV as BMI increased. The odds for successful ECV were estimated using multivariate logistic regression analysis, adjusting for possible confounders. Results A total of 51,002 patients with documented ECV were available for analysis. There was a decreased success rate for ECV as BMI increased (p Conclusions Morbidly obese women have decreased success rate of ECV as BMI increases and decreased vaginal delivery rates after successful ECV.

The risk of stillbirth associated with maternal obesity increases with gestational age; however, it is unclear if earlier delivery reduces the overall perinatal mortality rate. Our objective was to compare the risk of perinatal mortality associated with each additional week of expectant management to that of immediate delivery.This was a retrospective cohort study of singleton non-anomalous births in Texas between 2006 and 2011. Analyses were stratified based on maternal pre-pregnancy BMI class. For each BMI class, we calculated the rate of neonatal death and stillbirth at each week of gestation from 34 to 41 weeks. A composite risk of perinatal mortality associated with 1 week of expectant management was estimated combining the stillbirth rate of the current week and the neonatal death rate of the following week. This was compared with the rate of neonatal death of the current week.After all exclusions, 2,149,771 births remained for analysis. In the normal weight group, stillbirth risk increased from 0.8 per 10,000 births at 34 weeks to 5.7 per 10,000 births at 42 weeks, whereas the neonatal death risk decreased from 76.5 per 10,000 births at 34 weeks to 30.4 per 10,000 births at 42 weeks, there were no differences between expectant management and delivery for any gestational week. In the obese group, stillbirth risk increased from 1.8 per 10,000 births at 34 weeks to 10.5 per 10,000 births at 42 weeks, whereas the neonatal death risk decreased from 67.7 per 10,000 births at 34 weeks to 26.2 per 10,000 births at 42 weeks, the perinatal mortality risk favored delivery at 39 weeks (RR: 1.17; 99% CI: 1.01-1.36) and not thereafter. In contrast, in the morbidly obese group, stillbirth risk increased from 8.8 per 10,000 births at 34 weeks to 83.7 per 10,000 births at 42 weeks, whereas the neonatal death risk decreased from 63.6 per 10,000 births at 34 weeks to 15.5 per 10,000 births at 42 weeks, the perinatal mortality risk favored delivery from 38 weeks (RR: 1.53; 99% CI: 1.16-2.02) through 41 weeks (RR: 5.39; 99% CI: 1.83-15.88).The findings reported here suggest that delivery by 38 weeks in gestation minimizes perinatal mortality in pregnancies complicated by maternal morbid obesity.

An obesity-specific standard for small for gestational age (SGA) pregnancies may help identify additional at risk pregnancies.This was a retrospective cohort study of all non-anomalous singleton neonates born in Texas from 2006-2011. Analysis was limited to births between 34 and 42 weeks gestation. Two SGA birth weight standards (birth weight ≤10th centile) were generated, one using the entire population (SGAUsing the population standard, the prevalence of SGA complicated by obesity was 8.1%, compared with 10.3% using the obesity-specific standard. 10,457 additional pregnancies were identified as SGA. Compared to obese AGA pregnancies, the aHR for stillbirth was 5.45 [4.28, 6.94] for SGAUsing an obesity-specific SGA standard, a subgroup of pregnancies with marginally increased risk for neonatal complications was identified.

Purpose To estimate the risk of stillbirth associated with excessive and inadequate weight gain during pregnancy. Methods Retrospective cohort study using the Texas vital records database between 2006 and 2011, with 2,230,310 births (5502 stillbirths) was included for analysis. Pregnancies were categorized as adequate weight gain, excessive weight gain, inadequate weight gain, or weight loss based on the Institute of Medicine 2009 recommendations. Hazard ratios (HRs) for stillbirth were estimated for each gestational weight-gain stratum using adequate weight gain as the comparison group. The analysis was performed separately for each body mass index (BMI) class. Results Both inadequate weight gain and weight loss were associated with an increased risk of stillbirth for all BMI classes except the morbidly obese group. Highest risk was seen in weight-loss groups after 36 completed weeks (normal weight: HR = 18.85 [8.25–43.09]; overweight: HR = 5.87 [2.99–11.55]; obese: HR = 3.44 [2.34–5.05]). Weight loss was associated with reduced stillbirth risk in morbidly obese women between 24 and 28 weeks (HR = 0.56 [0.34–0.95]). Excess weight gain was associated with an increased risk of stillbirth among obese and morbidly obese women, with highest risk after 36 completed weeks (obese: HR = 2.00 [1.55–2.58]; morbidly obese: HR = 3.16 [2.17–4.62]). In contrast, excess weight gain was associated with reduced risk of stillbirth in normal-weight women between 24 and 28 weeks (HR = 0.57 [0.44–0.70]) and in overweight women between 29 and 33 weeks (HR = 0.62 [0.45–0.85]). Analysis for the underweight group was limited by sample size. Both excessive weight gain and inadequate weight gain were not associated with stillbirth in this group. Conclusions Stillbirth risk increased with inadequate weight gain and weight loss in all BMI classes except the morbidly obese group, where weight demonstrated a protective effect. Conversely, excessive weight gain was associated with higher risk of stillbirth among obese and morbidly obese women but was protective against stillbirth in lower weight women.

Objective Obesity is a known risk factor for stillbirth. However, this relationship has not been characterized fully. We attempted to further examine this relationship with a focus on delivery near and at term. Study Design We designed a retrospective cohort study of singleton nonanomalous live births and stillbirths in the states of Washington and Texas to examine the associations of maternal prepregnancy body mass index (BMI) and risk of stillbirth. Confounder-adjusted hazard ratio of stillbirth in relation to BMI was estimated through Cox proportional hazards regression model. The hazard ratio was used to estimate the population-attributable risk. We also estimated the fetuses who were at risk for stillbirth based on gestational age. Results Among 2,868,482 singleton births, the overall stillbirth risk was 3.1 per 1000 births (n = 9030). Compared with normal-weight women, the hazard ratio for stillbirth was 1.36 for overweight women, 1.71 for class I obese women, 2.00 for class II obese women, 2.48 for class III obese women, and 3.16 for women with a BMI of ≥50 kg/m2. The fetuses who are at risk for stillbirth increased after 39 weeks' gestation for each obesity class; however, the risk increased more rapidly with increasing BMI. Women with a BMI of ≥50 kg/m2 were at 5.7 times greater risk than normal weight women at 39 weeks' gestation and 13.6 times greater at 41 weeks' gestation. Obesity was associated with nearly 25% of stillbirth that occurred between 37 and 42 weeks' gestation. Conclusion There is a pronounced increase in the risk of stillbirth with increasing BMI; the association is strongest at early- and late-term gestation periods. Extreme maternal obesity is a significant risk factor for stillbirth.