Early Gestational Diabetes Screening Based on ACOG Guidelines.

OBJECTIVE: A recent randomized controlled trial suggested that early gestational diabetes mellitus (GDM) screening in patients with obesity (body mass index [BMI] ≥30 kg/m2) does not improve perinatal outcomes. The American College of Obstetrics and Gynecology currently recommends early screening for gestational diabetes in patients who are overweight with one or more additional risk factors. We evaluated the effect of screening based on the number of additional risk factors for development of gestational diabetes. STUDY DESIGN: This was a secondary analysis of a multicenter randomized controlled trial of obese patients with singleton nonanomalous fetuses comparing early (14-20 weeks' gestation) with routine (24-28 weeks' gestation) GDM screening. Exclusion criteria were pregestational diabetes, major medical illnesses, bariatric surgery, chronic steroid use, and prior cesarean. Early versus routine GDM screening groups were compared and stratified by the number of additional risk factors for GDM (0, 1, 2, and ≥3). The primary outcome was an adverse perinatal composite outcome composed of: macrosomia, primary cesarean delivery, hypertensive disorders of pregnancy, shoulder dystocia, neonatal hyperbilirubinemia, and neonatal hypoglycemia. Analyses examined effects of early versus routine screening by the number of additional risk factors and their possible interaction on the incidences of the primary outcome and GDM. RESULTS: Of 913 patients, 5% had 0, 52% had 1, 33% had 2, and 10% had ≥3 additional risk factors. Baseline characteristics, including the number and type of risk factors, were similar between early and routine screening groups. Breslow-Day test for interaction between early versus routine screening and the number of additional risk factors was not significant for either the primary outcome (p = 0.37) or the diagnosis of GDM (p = 0.28). The incidence of GDM and the adverse perinatal composite outcome increased as the number of risk factors increased (p < 0.001). CONCLUSION: In patients with BMI ≥30 kg/m2 and additional risk factors, early GDM screening does not prevent adverse outcomes. KEY POINTS: · The ACOG currently recommends early screening for gestational diabetes if patients have risk factors.. · Even in patients with multiple risk factors, early screening for GDM does not improve outcomes.. · Patients with three or more risk factors may have worse outcomes if they undergo early screening..

The Effects of Antepartum Depressive Symptoms on Postcesarean Opioid Consumption.

OBJECTIVE: The study aimed to test the hypothesis that higher Edinburgh Postnatal Depression Scale (EPDS) scores are associated with increased pain scores and opioid use during postpartum hospitalization following cesarean section. STUDY DESIGN: We conducted a retrospective cohort of English or Spanish-speaking women ≥18 years who had prenatal care for a singleton gestation and delivered by cesarean at ≥36 weeks within a tertiary center during 2017. Exclusions included women with fetal anomalies, intrauterine fetal demise, sickle cell disease, previously diagnosed pain disorders (e.g., chronic pain or fibromyalgia), substance use disorder (based on documented prescription or use of methadone or buprenorphine), or reoperation during hospital stay. Women without an EPDS recorded antenatally were also excluded. Major depressive symptoms (MDS) were defined as a documented antenatal EPDS ≥12. Women with and without MDS were compared, and multivariable linear regression models were generated to evaluate associations between MDS status and both pain scores and opioid use. RESULTS: Of the 891 women meeting other inclusion criteria, 676 (76%) had documented antenatal EPDS scores, and 104 (15.4%) of those had MDS. Women with MDS were more likely to be use tobacco and have general anesthesia for cesarean delivery, but groups were otherwise similar. Women with MDS reported higher daily and average pain scores postpartum (2.4 vs. 1.7 average; p < 0.001). Women with MDS used more morphine milligram equivalents (MME) each day during their postpartum hospitalization, leading to a higher total MME use (121 mg [60.5-214.5] vs. 75 mg [28.5-133.5], p < 0.001). CONCLUSION: We found an association between antepartum depressive symptoms and acute pain after cesarean delivery leading to increased opioid use. Given the current focus on opioid stewardship, further research into this association, exploration of tailored pain control, and determining whether treatment of antepartum MDS reduces postpartum pain, and therefore opioid use, will be of the utmost priority. KEY POINTS: · Women with MDS report higher pain scores postcesarean.. · Women with MDS use more opioids postcesarean.. · Future studies are needed for the treatment of MDS..

Uterine myomas: effect of prior myomectomy on pregnancy outcomes.

OBJECTIVE: Reproductive aged women with fibroids must weigh the risks and benefits of preconception myomectomy. Women with fibroids may have higher rates of fetal growth restriction (FGR) and stillbirth; however, there is a paucity of data on the impact of myomectomy on pregnancy outcomes. We compared perinatal outcomes in women with prior myomectomy versus those with no prior myomectomy and at least one fibroid ≥ 5 cm. METHODS: Retrospective cohort study of women at a single center who delivered between 2008 and 2017 with a viable intrauterine pregnancy at initial ultrasound scan and either prior myomectomy, or, in the no-myomectomy cohort, at least one fibroid ≥ 5 cm on a prenatal scan performed at < 21 weeks' gestation (wga). Pregnancies complicated by major congenital anomalies were excluded. Primary outcome was preterm birth (PTB) < 37wga. Secondary outcomes included rates of spontaneous loss, cesarean delivery (CD), abnormal placentation, malpresentation, FGR, birthweight, birthweight percentile, estimated blood loss (EBL), blood transfusion, and neonatal survival to discharge. RESULTS: A total of 290 women met inclusion criteria: 70 had a prior myomectomy, 220 women had ≥1 fibroid ≥5cm. Women with prior myomectomy were older, more likely to have private insurance, and more likely used artificial reproductive technology to conceive; 20% with prior myomectomy still had at least one ≥ 5 cm myoma on their obstetric scan. Rates of spontaneous loss were lower in the prior myomectomy group (1.4% vs 7.3%; p = .08). Of the 273 pregnancies continuing beyond 20 weeks, women with prior myomectomy had significantly more PTBs (35% vs. 21%, p = .02) and significantly different primary birth indications (p < .0001). However, after controlling for late preterm, prelabor cesareans recommended by providers in the myomectomy cohort, the difference in PTB rates was not significant (p = .13). The myomectomy group had more CDs (88% vs. 53%, p < .0001), higher EBL (1250 mL vs. 811 mL, p = .04), and a trend toward more blood transfusions (16% vs 8%, p = .05). Other selected outcomes were similar, including rates of FGR. CONCLUSIONS: Women with prior myomectomy had significantly more PTBs, due in part to more preterm, prelabor cesareans in the late preterm period. Otherwise, prior myomectomy did not confer appreciable obstetric or perinatal benefits, as patients had more CDs, and higher EBL. Recommendations to perform preterm prelabor cesareans in this population may explain some of the PTB disparity. The effect of prior myomectomy on early pregnancy loss and infertility requires further study.

Intrapartum opioid analgesia and childhood neurodevelopmental outcomes among infants born preterm.

BACKGROUND: There are concerns regarding neurobehavioral changes in infants exposed to parenteral opioids during labor; however, long-term neurodevelopment remains unstudied. OBJECTIVE: We aimed to examine the association between parenteral opioids used as labor analgesia and perinatal outcomes and childhood neurodevelopment until 2 years of age among infants born prematurely. We hypothesized that intrapartum exposure to parenteral opioids is associated with impaired neurodevelopment and adverse perinatal outcomes. STUDY DESIGN: This was a secondary analysis of a multicenter, randomized controlled trial assessing magnesium for the prevention of cerebral palsy in infants at risk for preterm birth. Women delivering a singleton, nonanomalous, live infant before 37 weeks' gestation were considered for inclusion. Women were excluded if they had missing exposure or primary outcome data, were exposed to general anesthesia, or reported use of heroin or unspecified illicit drugs. Women reporting use of nonopioid illicit drugs such as cocaine and marijuana were not excluded. Groups were compared based on exposure or nonexposure to parenteral opioids (intravenous or intramuscular) used as labor analgesia. The primary outcome was any psychomotor or mental developmental delay at 24 months according to the Bayley Scales of Infant Development II. Secondary outcomes were the Bayley Scales of Infant Development II subdomains and adverse perinatal outcomes. Multivariable logistic regression models were performed and adjusted odds ratios with 95% confidence intervals were estimated. RESULTS: Of the 1404 women included, 535 (38%) received parenteral opioids as labor analgesia. Women receiving parenteral opioids were more likely to be younger, Hispanic, and present with cervical dilation ≥4 cm. Parenteral opioid recipients had lower rates of illicit nonopioid drug or tobacco use, a lower rate of cesarean delivery, lower educational level and were less likely to be undergoing induction. Women receiving parenteral opioids who underwent cesarean delivery were less likely to do so because of a nonreassuring fetal status. In the unadjusted and adjusted analyses, there were no significant differences in the primary outcomes of psychomotor or mental developmental delay at 2 years of age (adjusted odds ratio, 0.96; confidence interval, 0.76-1.20). The only significant difference in secondary outcomes was a shorter O2 requirement duration in the parenteral opioid group (2 vs 4 days; P=.002). CONCLUSION: Among a population of preterm infants vulnerable to neurologic impairment, intrapartum exposure to parenteral opioids was not associated with an increased risk for neurodevelopmental delay up to 2 years of age, nor did these infants have worse perinatal outcomes.

Prenatal Tobacco Exposure and Childhood Neurodevelopment among Infants Born Prematurely.

OBJECTIVE: Nicotine is an established neuroteratogen, and prenatal tobacco exposure alters the structure of the developing nervous system. An association between prenatal tobacco exposure and impaired neurologic function is less well established. We examine the association between prenatal tobacco exposure and childhood neurodevelopment among infants born preterm. STUDY DESIGN: Secondary analysis of a multicenter randomized controlled trial assessing the benefits of magnesium sulfate for the prevention of cerebral palsy in preterm infants. Women were included if they delivered a singleton and nonanomalous infant before 37 weeks. Exposure was any self-reported prenatal tobacco use. Primary outcome was the original trial composite outcome of moderate or severe cerebral palsy at 2 years of age, or stillbirth, or infant death by 1 year of age. Secondary outcomes included components of the composite and mild cerebral palsy at 2 years, Bayley Scales of Infant Development II motor and mental scores, death before two years, and use of auditory aids or corrective lenses. Multivariable logistic regression models were performed to estimate adjusted odds ratios (aOR) with 95% confidence intervals. RESULTS: Of 1,826 women included, 503 (27.5%) used tobacco. Tobacco users were more likely to be older, unmarried, and white; have a prior preterm birth; have received no prenatal care; and to use illicit drugs or alcohol. Gestational age at delivery, betamethasone exposure, and magnesium exposure were not different between groups. There were no differences in the composite primary outcome or in rates of cerebral palsy by tobacco use. Moderate developmental delay was more common among tobacco exposed in bivariate but not adjusted analysis (20.5 vs. 15.9%, p = 0.035). In adjusted analysis, tobacco exposure was associated with increased use of corrective lenses (5.0 vs. 2.9%, aOR: 2.28, 95% confidence interval: 1.28-4.07). CONCLUSION: Prenatal tobacco exposure is not associated with neurodevelopmental impairment in infants born preterm. However, tobacco exposure may be associated with impaired vision. KEY POINTS: · Tobacco exposure is not associated with impaired neurodevelopment in this preterm population.. · Prenatal tobacco exposure is associated with increased need for corrective lenses.. · Tobacco use in pregnancy may be a risk factor for poorer visual acuity in children..

Early gestational diabetes screening in obese women: a randomized controlled trial.

BACKGROUND: Although in 2013 the American College of Obstetricians and Gynecologists recommended early screening for gestational diabetes in obese women, no studies demonstrate an improvement in perinatal outcomes with this strategy. OBJECTIVE: We sought to determine whether early screening for gestational diabetes improves perinatal outcomes in obese women. MATERIALS AND METHODS: Randomized controlled trial comparing early gestational diabetes screening (14-20 weeks) to routine screening (24-28 weeks) in obese women (body mass index ≥30 kg/m2) at 2 tertiary care centers in the United States. Screening was performed using a 50-g, 1-hour glucose challenge test followed by a 100-g, 3-hour glucose tolerance test if the initial screen was ≥135 mg/dL. Gestational diabetes was diagnosed using Carpenter-Coustan criteria. Women not diagnosed at 14 to 20 weeks were rescreened at 24 to 28 weeks. Exclusion criteria were pre-existing diabetes, major medical illness, bariatric surgery, and prior cesarean delivery. The primary outcome was a composite of macrosomia (>4000 g), primary cesarean delivery, hypertensive disease of pregnancy, shoulder dystocia, neonatal hyperbilirubinemia, and neonatal hypoglycemia (assessed within 48 hours of birth). RESULTS: A total of 962 women were randomized, and outcomes were available for 922. Of these 922 women, 459 (49.8%) were assigned to early screen and 463 (50.2%) to routine screen. Baseline characteristics were balanced between groups. In the early screening group, 69 (15.0%; 95% confidence interval, 11.9-18.6%) were diagnosed with gestational diabetes: 29 (6.3%; 95% confidence interval, 4.3-8.9%) at <20 weeks and 40 (8.7%; 95% confidence interval, 6.3-11.7%) at >24 weeks. Of those randomized to routine screening, 56 (12.1%; 95% confidence interval, 9.3-15.4%) had gestational diabetes. Early screening did not reduce the incidence of the primary outcome (56.9% in the early screen versus 50.8% in the routine screen, P = .07; relative risk, 1.12; 95% confidence interval, 0.99-1.26). CONCLUSION: Early screening for gestational diabetes in obese women did not reduce the composite perinatal outcome.

Neonatal Outcomes Based on Duration of Exposure to Antenatal Corticosteroids in Indicated Preterm Deliveries.

OBJECTIVE: To evaluate how duration of exposure to antenatal corticosteroids (ACSs) prior to delivery affects neonatal outcomes in indicated preterm deliveries. STUDY DESIGN: This is a retrospective cohort of all indicated singleton preterm deliveries (23-34 weeks) in a single tertiary center from 2011 to 2014 comparing those who received ACS 2 to 7 days versus >7 days prior to delivery. The primary neonatal outcome was a composite of arterial cord pH < 7 or base excess ≤ 12, 5-minute Apgar ≤ 3, cardiopulmonary resuscitation, culture-proven neonatal sepsis, intraventricular hemorrhage grade III/IV, necrotizing enterocolitis, and neonatal death. Analyses were stratified by delivering gestational age (230/7-276/7, 280/7-316/7, and 320/7-336/7 weeks). Multivariate logistic regression refined point estimates and adjusted for confounders. RESULTS: In total, 301 women delivered >48 hours after initial ACS dose, 230 delivered within 2 to 7 days, and 71 delivered >7 days. Infants with an interval of >7 days had no significant increase in the unadjusted composite neonatal outcome (p = 0.42), but when adjusted, the composite neonatal outcome (adjusted odds ratio [AOR]: 2.7; 95% confidence interval [CI]: 1.18-6.31) and neonatal death (AOR: 4.20; 95% CI: 1.39-12.69) were significantly increased with an ACS interval of >7 day. CONCLUSION: In this cohort, the benefit of ACS diminished >7 days after administration, particularly when delivery occurred at <32 weeks.

Fellow Perceptions of Residency Training in Obstetrics and Gynecology.

OBJECTIVE: To evaluate the perceptions of current and former fellows in obstetrics and gynecology (OBG) subspecialties of their readiness for fellowship training. METHODS: A previously used survey was modified and distributed in 2016 to current and former fellows in gynecologic oncology, maternal-fetal medicine, reproductive endocrinology-infertility, and female pelvic medicine and reconstructive surgery. The survey explored domains of professionalism, independent practice, psychomotor ability, clinical evaluation, and scholarship. A standard Likert scale was employed and domains/responses were tailored to each subspecialty. Standard statistical models were utilized. RESULTS: A total of 478 fellows responded to the survey. Nearly 75% of fellows from each specialty reported feeling prepared or very prepared for fellowship. More than 65% of fellows from each specialty reported feeling very prepared to perform core surgical procedures. More than 90% of respondents reported having opportunities during residency to independently develop a plan of action for patients on labor and delivery. Fewer respondents reported opportunities to independently manage postoperative complications-40.7% of gynecologic oncology and 44.7% of female pelvic medicine and reconstructive surgery reported having such opportunities, whereas 91.9% of maternal-fetal medicine respondents reported having had such opportunities. While 46.4% of respondents received education on scientific writing during residency, 80% reported writing a manuscript as a resident. CONCLUSIONS: The majority of current and former fellows in OBG subspecialties report feeling prepared for fellowship in terms of clinical and surgical skills. Their feedback reveals opportunities for improvement of independent practice in gynecologic scenarios, as well as formal education on scientific research, for OBG residencies.

The effect of omega-3 supplementation on pregnancy outcomes by smoking status.

BACKGROUND: Smoking during pregnancy is associated with adverse maternal and neonatal outcomes such as preterm delivery, intrauterine growth restriction, stillbirth, and low birth weight. Because smoking causes oxidative stress, some have suggested using antioxidants to counteract the effects of oxidative stress. Smokers have lower serum levels of omega-3 fatty acids, an important antioxidant, and thus, investigating whether omega-3 supplementation in smokers reduces adverse maternal and neonatal outcomes represents an important area of research. OBJECTIVE: To investigate whether the antioxidant effect of omega-3 fatty acid supplementation on the incidence of adverse pregnancy outcomes differs between smokers and nonsmokers. STUDY DESIGN: Secondary analysis of a multicenter randomized controlled trial of omega-3 supplementation for preterm delivery prevention in women with a singleton pregnancy and a history of a previous singleton spontaneous preterm delivery. Subjects were randomized to begin omega-3 or placebo before 22 weeks, which was continued until delivery. All women received 17 alpha-hydroxyprogesterone caproate intramuscularly weekly beginning between 16 and 20 weeks of gestation and continued until 36 weeks of gestation or delivery, whichever occurred first. The primary outcome was spontaneous preterm delivery. Secondary outcomes were indicated preterm delivery, any preterm delivery (spontaneous and indicated), pregnancy-associated hypertension (gestational hypertension and preeclampsia), a neonatal composite (retinopathy of prematurity, intraventricular hemorrhage grade III or IV, patent ductus arteriosus, necrotizing enterocolitis, sepsis, respiratory morbidity, or perinatal death), low birth weight (<2500 g), small for gestational age (less than the 10th percentile), and neonatal intensive care unit or intermediate nursery admission. The study population was stratified into smokers and nonsmokers, and the incidence of each outcome was compared by omega-3 supplementation versus placebo in each subgroup. Zelen tests were performed to test for homogeneity of effect in smokers and nonsmokers. RESULTS: Of 851 subjects included in the analysis, 136 (16%) smoked. Baseline characteristics between omega-3 and placebo groups did not differ in smokers or nonsmokers. Omega-3 supplementation was associated with a lower risk of spontaneous preterm delivery in smokers (relative risk, 0.56, 95% confidence interval, 0.36-0.87) but not in nonsmokers (relative risk 1.04, 95% confidence interval 0.84-1.29); P value for interaction = 0.013. Low birth weight was also less frequent in smokers receiving omega-3 supplementation (relative risk 0.57, 95% confidence interval 0.36-0.90) compared with nonsmokers (relative risk 0.93, 95% confidence interval 0.71-1.24); P value for interaction = 0.047. The effect on other secondary outcomes did not differ significantly between smokers and nonsmokers. CONCLUSION: Omega-3 supplementation in smokers may have a protective effect against recurrent spontaneous preterm delivery and low birth weight.

Early warning score: An indicator of adverse outcomes in postoperative patients on a gynecologic oncology service.

OBJECTIVE: In 2014, our hospital implemented an early warning score (EWS) to identify inpatients at risk for clinical deterioration. EWS≥8 is associated with ≥10% mortality in medical admissions. Since postoperative hemodynamic changes may alter EWS, we evaluated EWS in post-laparotomy patients. METHODS: Gynecologic oncology patients admitted for laparotomy from 9/1/2014 to 7/31/2015 were categorized by highest EWS during admission: <5, 5-7, and ≥8. The primary outcome was a composite including death, ICU transfer, rapid response team activation, pulmonary embolus, sepsis, and reoperation. For patients with the composite, highest EWS prior to that outcome was evaluated. Secondary outcomes were length of stay (LOS), readmission, and transfusion. Groups were compared using chi-square test for trend, analysis of variance, and Kruskal-Wallis tests. A receiver operating characteristic (ROC) curve estimated the association between EWS and the composite outcome. RESULTS: 411 patients were included: 217 (52.8%) with EWS<5, 151 (36.7%) with EWS 5-7, and 43 (10.5%) with EWS≥8. The composite occurred in 32.6% of patients with EWS≥8, 7.3% with EWS 5-7, and 0% with EWS<5 (p<0.01). EWS≥8 was associated with longer LOS, higher readmission rate, and more transfusions. For the composite, the area under the ROC curve was 0.89 (95% CI 0.84-0.94). EWS≥5 had 100% sensitivity and 56.2% specificity for the primary outcome; EWS≥8 had 56.0% sensitivity and 92.5% specificity for the primary outcome. CONCLUSIONS: EWS≥5 after laparotomy is associated with adverse outcomes. Future studies should evaluate the ability of EWS to predict and prevent these outcomes.

Impact of Early Screening for Gestational Diabetes on Perinatal Outcomes in High-Risk Women.

Objective To examine the benefits of early gestational diabetes mellitus (GDM) screening in a high-risk population. Study Design Retrospective cohort of all singletons diagnosed with GDM with indications for early screening: GDM or macrosomia in a prior pregnancy or obesity. Subjects were classified as early (<20 weeks) or routine (>24 weeks) screening. Patients diagnosed with GDM were managed according to standard institutional protocols. Outcomes examined were cesarean delivery (CD), preeclampsia, large for gestational age (LGA), small for gestational age (SGA), macrosomia, and preterm birth (PTB). Results Subjects screened early were more likely to have had GDM in a prior pregnancy, hypertension, higher body mass index, and higher fasting glucose. Early and routine screening groups had similar incidences of CD (adjusted odds ratio [AOR] 0.95, 95% confidence interval [CI] 0.55-1.64), preeclampsia (AOR 0.84, 95% CI 0.38-1.83), LGA (AOR 0.90, 95% CI 0.51-1.72), SGA (AOR 0.38, 95% CI 0.13-1.13), and macrosomia (AOR 1.00, 95% CI 0.53-1.87). Subjects in the early screening group had a higher incidence of PTB (AOR 1.79, 95% CI 1.08-2.99). Conclusion We did not detect a benefit to early screening for women who met the criteria. The utility of early GDM screening requires evaluation in a prospective trial.

Preparedness of Obstetrics and Gynecology Residents for Fellowship Training.

OBJECTIVE: To evaluate the perceptions of fellowship program directors of incoming clinical fellows for subspecialty training. METHODS: A validated survey by the American College of Surgeons was modified and distributed to all fellowship program directors in four subspecialties within obstetrics and gynecology: female pelvic medicine and reconstructive surgery, gynecologic oncology, maternal-fetal medicine, and reproductive endocrinology-infertility. The 59-item survey explored five domains concerning preparedness for fellowship: professionalism, independent practice, psychomotor ability, clinical evaluation, and academic scholarship. A Likert scale with five responses was used and tailored to each subspecialty. Standard statistical methods were used to compare responses between subspecialties and to analyze data within each subspecialty individually. RESULTS: One hundred thirty directors completed the survey, for a response rate of 60%. In the domain of professionalism, more than 88% of participants stated that incoming fellows had appropriate interactions with faculty and staff. Scores in this domain were lower for gynecologic oncology respondents (P=.046). Responses concerning independent practice of surgical procedures (hysterectomy, pelvic reconstruction, and minimally invasive) were overwhelmingly negative. Only 20% of first-year fellows were able to independently perform a vaginal hysterectomy, 46% an abdominal hysterectomy, and 34% basic hysteroscopic procedures. Appropriate postoperative care (63%) and management of the critically ill patient (71%) were rated adequate for all subspecialties. CONCLUSION: Graduating residents may be underprepared for advanced subspecialty training, necessitating an evaluation of the current structure of resident and fellow curriculum. LEVEL OF EVIDENCE: III.

Effect of maternal obesity on the risk of fetal loss after amniocentesis and chorionic villus sampling.

OBJECTIVE: To estimate the risk of fetal loss in obese women undergoing amniocentesis and chorionic villus sampling (CVS). METHODS: This was a retrospective cohort study of all women undergoing amniocentesis or CVS. The primary outcome was any fetal loss before 24 weeks of gestation. A secondary analysis was performed examining pregnancy loss within 14 days of the procedure, excluding termination of pregnancy. Obese (body mass index [BMI] 30.0 or higher) and nonobese (BMI lower than 30.0) patients were compared, and the postprocedure loss rate was also estimated by BMI strata. Obese and nonobese patients were compared with univariable and bivariate statistics; multivariable logistic regression models were developed to estimate the effect of maternal obesity. RESULTS: Between obese (n=2,742) and nonobese (n=8,037) women undergoing amniocentesis, no difference existed in the risk of fetal loss before 24 weeks of gestation (4.7% [combined background and procedure loss] compared with 4.2%, adjusted odds ratio [OR] 1.1, 95% confidence interval [CI] 0.8-1.5). For women undergoing CVS, no difference in the risk of pregnancy loss was seen between obese (n=855) and nonobese (n=4,125) women (6.4% compared with 6.3%, adjusted OR 1.0, 95% CI 0.7-1.3). Compared with women not undergoing a procedure, the attributable risk for obese women was 0.3% (95% CI -0.2 to 0.9) amniocentesis and 0.1% (95% CI -0.1 to 0.2) CVS. The difference in fetal loss between the BMI 40.0 or higher and BMI lower than 25.0 groups after amniocentesis was significant after adjusting for maternal age (adjusted OR 2.2, 95% CI 1.2-3.9). This study had greater than 90% power to detect a 50% increase in the risk of pregnancy loss after amniocentesis and CVS (with an α error of 0.05). CONCLUSION: A BMI of 30.0-40.0 does not increase the risk for fetal loss after invasive prenatal diagnostic procedures. A higher loss rates with class III obesity (BMI 40.0 or higher) was observed for amniocentesis procedures. LEVEL OF EVIDENCE: II.