Influence of preconception body mass index on perinatal outcomes after metabolic and bariatric surgery.

Introduction: Metabolic and bariatric surgery (MBS) is a very effective weight loss intervention, although does not invariably reverses the obesity status. Our aim was to evaluate whether despite successful weight loss after MBS, persistence of obesity at time of conception still carries additional risks of adverse perinatal pregnancy outcomes.

Methods: Retrospective study comparing pregnancy outcomes of women previously submitted to MBS with a preconception (PC) body mass index BMI < 30 kg/m or PC BMI ≥ 30 kg/m.

Results: Eighty pregnancies (n = 80) were included, 49 from women with a PC BMI < 30 kg/m and 31 with a PC BMI ≥ 30 kg/m. Gestational weight gain was significantly lower (9.72 ± 7.10 vs. 13.81 ± 7.16 respectively; p = 0.01) and neonatal intensive care unit admissions were significantly higher (5% vs. 0% respectively; p = 0.02) in women with PC BMI ≥ 30 kg/m as compared to those with PC BMI < 30 kg/m. There were no statistically significant differences in gestational diabetes, anemia, fetal growth restriction, prematurity rate, mode of delivery or birth weight between groups.

Conclusion: Perinatal outcomes of pregnancies after MBS may be significantly influenced by PC BMI. The benefits of MBS induced weight loss on obesity-associated adverse pregnancy outcomes can be maximized if the obesity status can be reverted before pregnancy.