Endocrine Abstracts

Introduction: Maternal obesity is associated with an increased risk of gestational diabetes, large for gestational age (LGA) newborns, preterm delivery, congenital malformations, and fetal death. On the other hand, bariatric surgery before pregnancy is associated with a reduction of obesity-associated complications, but also with an increased risk of small for gestational age (SGA) newborns, fetal growth restriction and micronutrient deficiencies during pregnancy.

Aim: To evaluate the effect of bariatric surgery on maternal and fetal outcomes.

Methods: This was a retrospective observational study that included pregnant women followed by a multidisciplinary obesity team in a tertiary hospital, from September 2019 to March 2022. Participants were included in one of two groups: (1) women with a history of gastric bypass or sleeve gastrectomy before pregnancy (n=83); (2) women with BMI≥35 kg/m², without a history of bariatric surgery (n=166). Participants with loss of follow-up were excluded. Medical files were review for demographic and clinical data. Statistical analysis was performed using IBM SPSS Statistics 27. Multivariate analysis was performed to adjust for the following confounders: BMI prior to surgery in group (1) and BMI prior to pregnancy in group (2), maternal age, smoking during pregnancy, and history of thyroid dysfunction or essential hypertension.

Results: After adjusting for confounders, pregnancy after bariatric surgery was associated with higher gestational weight gain (10.97±7.08 vs 7.21±5.95, β=0.294, P<0.001), newborns with lower weigh percentile (36.85±20.93 vs 48.47±27.90, β=−13.327, P<0.001), an increased risk of iron deficiency (81.8% vs 67.2%, OR 2.480, P=0.013) and vitamin B12 deficiency (44.0% vs 24.4%, OR 2.357, P=0.016), and lower rates of gestational diabetes (16.9% vs 32.5%, OR 0.359, P=0.003), and cesarian section (22.9% vs 34.7%, OR 0,518, P=0.044). No statistically significant differences were observed between groups regarding preterm delivery (12.0% vs 6.0%, OR 2.422, P=0.083), gestational hypertension (4.8% vs 9.6%, OR 1.573, P=0.608), preeclampsia (2.4% vs 7.2%, OR 0.545, P=0.548) or fetal growth restriction (4.8% vs 0.6%, OR 11.247, P=0.062).

Conclusion: Pregnancy after bariatric surgery was associated with a lower risk of gestational diabetes and cesarian section, and a higher risk of micronutrient deficiencies. Risks and benefits of bariatric surgery before pregnancy must be considered in the decision making of obesity treatment in women of fertile age.