LAUSR

Importance Metabolic changes after maternal bariatric surgery may affect subsequent fetal development. Many relevant perinatal outcomes have not been studied in this postoperative population, and the risks associated with short operation-to-birth (OTB) intervals have not been well examined. Objective To examine the risk for perinatal complications in women with a history of bariatric surgery (postoperative mothers [POMs]) by comparing them with mothers without operations (nonoperative mothers [NOMs]) and examining the association of the OTB interval with perinatal outcomes. Design, Setting, and Participants This investigation was a population-based retrospective cohort study (January 1, 1980, to May 30, 2013) at hospitals in Washington State. Data were collected from birth certificates and maternally linked hospital discharge data. Participants were all POMs and their infants (n = 1859) and a population-based random sample of NOMs and their infants frequency matched by delivery year (n = 8437). Exposures Bariatric operation before birth or categories of OTB intervals. Main Outcomes and Measures The primary outcomes were prematurity, neonatal intensive care unit (NICU) admission, congenital malformation, small for gestational age (SGA), birth injury, low Apgar score (⩽8), and neonatal mortality. Poisson regression was used to compute relative risks (RRs) and 95% CIs, with adjustments for maternal body mass index, delivery year, socioeconomic status, age, parity, and comorbid conditions. Results A total of 10 296 individuals were included in the analyses for this study. In the overall cohort, the median age was 29 years (interquartile range, 24-33 years). Compared with infants from NOMS, infants from POMs had a higher risk for prematurity (14.0% vs 8.6%; RR, 1.57; 95% CI, 1.33-1.85), NICU admission (15.2% vs 11.3%; RR, 1.25; 95% CI, 1.08-1.44), SGA status (13.0% vs 8.9%; RR, 1.93; 95% CI, 1.65-2.26), and low Apgar score (17.5% vs 14.8%; RR, 1.21; 95% CI, 1.06-1.37). Compared with infants from mothers with greater than a 4-year OTB interval, infants from mothers with less than a 2-year interval had higher risks for prematurity (11.8% vs 17.2%; RR, 1.48; 95% CI, 1.00-2.19), NICU admission (12.1% vs 17.7%; RR, 1.54; 95% CI, 1.05-2.25), and SGA status (9.2% vs 12.7%; RR, 1.51; 95% CI, 0.94-2.42). Conclusions and Relevance Infants of mothers with a previous bariatric operation had a greater likelihood of perinatal complications compared with infants of NOMs. Operation-to-birth intervals of less than 2 years were associated with higher risks for prematurity, NICU admission, and SGA status compared with longer intervals. These findings are relevant to women with a history of bariatric surgery and could inform decisions regarding the optimal timing between an operation and conception.