Bariatric surgery in women of child-bearing age, timing between an operation and birth, and associated perinatal complications

Thesis (Master's)--University of Washington, 2016-06

University of Washington Abstract Bariatric surgery in women of child-bearing age, timing between an operation and birth, and associated perinatal complications Brodie Parent, MD Chair of the Supervisory Committee: Dr. Ali Rowhani-Rahbar, MD, PhD, Assistant Professor Department of Epidemiology Importance: Metabolic changes after maternal bariatric surgery may impact 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: 1) To assess perinatal complications in postoperative mothers (‘POMs’) compared to mothers without operations (non-operative mothers, ‘NOMs’). 2) To examine the association of the OTB interval with perinatal outcomes. Design: Population-based retrospective cohort study from 1980-2013. Data were collected from birth certificates and maternally-linked hospital discharge data. Setting: Hospitals in Washington State Participants: a) All POMs and their infants (n=1,859); b) a population-based random sample of NOMs and their infants, frequency-matched by delivery year (n=8,437). Exposures: a) Bariatric operation prior to birth or b) categories of OTB intervals. Main Outcomes and Measures: 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 (RR) and confidence intervals (CI), with adjustments for maternal body mass index, delivery year, socioeconomic status, age, parity, and co-morbid conditions. Results: Compared to infants from NOMS, infants from POMs had a higher risk for prematurity (14% vs. 9%, RR 1.6, 95% CI 1.3-1.9), NICU admission (15% vs. 11%, RR 1.3, 95% CI 1.1-1.4), SGA status (13% vs. 9%, RR 1.9, 95% CI 1.7-2.3), and low APGAR scores (18% vs. 15%, RR 1.2, 95% CI 1.1-1.4). Compared to infants from mothers with a ≥4 year OTB interval, infants from mothers with a ≤2 year interval had higher risks for prematurity (RR 1.5, 95% CI 1.0-2.2), NICU admission (RR 1.5, 95% CI 1.1-2.3), and SGA status (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 to infants of non-operative mothers. Operation-to-birth intervals <2 years were associated with higher risks for prematurity, SGA status, and NICU admission, compared to longer intervals. These findings are relevant to bariatric surgeons, obstetricians, and their patients, and could inform decisions regarding the optimal timing between an operation and conception. Supplementary material included: Figure 1, 2 and 3: Flow diagram, epidemiologic birth trends, and forest plot of risk estimates Supplemental Tables 1 and 2: risks associated with operation-to-birth intervals