Maternal and neonatal outcomes after metabolic and bariatric surgery among women with severe obesity.

Background: Earlier evidence indicated that metabolic and bariatric surgery (MBS) may adversely affect neonatal outcomes among patients conceiving soon after MBS, but recent studies demonstrated conflicting results, especially for new surgical techniques.

Objectives: The aim of this study was to assess the effects of MBS types and surgery to birth interval on maternal, birth, and nonbirth outcomes in women with severe obesity.

Setting: New York State's all-payer hospital discharge database (2008-2019).

Methods: We identified women with severe obesity who underwent MBS (Post-MBS, n = 5001) or did not undergo MBS (No-MBS, n = 74,515), and examined maternal, neonatal, and nonbirth outcomes by MBS type and time since surgery in a propensity score-matched sample.

Results: Compared with No-MBS mothers, Post-MBS mothers had a lower incidence of stillbirths, ectopic pregnancies, and miscarriages (nonoverlapping confidence intervals). Post-MBS mothers were also significantly less likely to have pregnancy hypertension, gestational diabetes, and cesarean deliveries, but were more likely to experience vaginal bleeding during early pregnancy and deliver low birthweight newborns compared with No-MBS mothers (P < .05). Among Post-MBS mothers, deliveries within 18 months after surgery were associated with higher rate of cesarean sections and neonatal deaths compared with deliveries 18+ months after MBS (P < .05). Pregnancies after gastric bypass (RYGB) were more likely to result in cesarean deliveries compared with pregnancies after sleeve gastrectomy (P < .01).

Conclusions: Although weight loss surgery in women with obesity may reduce the rates of adverse maternal nonbirth outcomes and pregnancy complications, neonates born to women who conceived during the first year after MBS, especially RYGB, may be at higher risk for adverse outcomes.