Twin pregnancy outcomes after metabolic and bariatric surgery.

BACKGROUND: The effect of bariatric surgery (BS) on twin pregnancy outcomes is unclear. OBJECTIVES: We examined associations of BS with maternal and perinatal outcomes among women with twin gestation. SETTING: A university hospital. METHODS: A retrospective case-control study of twin deliveries during 2006 through 2017. The study group comprised all women with twin pregnancy who had undergone BS and delivered during the study period. A control group was established by matching preoperative body mass index, age, parity, and delivery year. RESULTS: Data from 66 women with twin gestation were analyzed, 22 postBS and 44 matched control parturients. Compared with the control group, the study group had lower rates of gestational diabetes (9.1% versus 36.4%, P = .02) and gestational hypertensive disorders (0% versus 25.0%, P = .01); hemoglobin levels were lower at both early pregnancy (median 12.3 versus 13.4 g/dL, P < .001) and after delivery (9.3 versus 10.5 g/dL, P < .001). Median neonatal birthweights and the proportion of small-for-gestational-age infants were comparable between the groups. The degree of birth weight discordance between the twins was higher (17.2% versus 8.8%, P < .001) in the control group. CONCLUSIONS: In this study involving twin gestations, pregnancy outcomes were more positive among women who had undergone BS; as noted by reduced prevalences of gestational diabetes and gestational hypertensive disorders as well as a lesser degree of birth weight discordance. Nevertheless, BS was associated with lower hemoglobin levels during pregnancy and the postpartum period. Future studies are warranted to confirm our findings and evaluate the long-term outcomes of newborns of postBS mothers.