Pregnancy Outcomes After One Anastomosis Gastric Bypass

Background: One anastomosis gastric bypass (OAGB) is gaining increasing acceptance worldwide. Pregnancy outcomes after OAGB have been understudied. We aimed to examine associations of OAGB with maternal and perinatal outcomes. Methods: The study group comprised women who delivered after OAGB during 2017-2024 in a university hospital. A control group was established by matching preoperative body mass index, age, delivery history, and delivery year. Results: Overall, 50 OAGB and 50 matched control parturients were included. In the OAGB group, rates of gestational hypertensive disorders (2.0% vs. 10.0%, P = 0.008) and gestational diabetes mellitus (4.0% vs. 18.0%, P = 0.05) were significantly lower compared with the control group. For the OAGB group, hemoglobin levels were lower at both early pregnancy (11.5 vs. 13.1 g/dL, P < 0.001) and pre-delivery (10.4 vs. 10.9 g/dL, P = 0.008), with a higher proportion of patients requiring intravenous iron supplementation (24.0% vs. 2.0%, P = 0.002). Rate of induction of labor was lower within the OAGB group (12.5% vs. 36.1%, P = 0.03), while gestational age at delivery and mode of delivery were similar between the groups. For the OAGB group, birthweight was significantly lower (2900 vs. 3392 grams, P < 0.001) with a higher proportion of small-for-gestational-age infants (28.0% vs. 6.0%, P = 0.006) and a lower proportion of large-for-gestational-age infants (2.0% vs. 24.0%, P = 0.002). Conclusions: OAGB was associated with reduced rates of gestational diabetes mellitus, gestational hypertensive disorders, excessive fetal growth, and induction of labor; and an increased rate of small-for-gestational-age infants. Hemoglobin levels were lower throughout pregnancy among OAGB patients, with a higher incidence of intravenous iron supplementation.