805: Pregnancy after bariatric surgery: What is the association between time from surgery and maternal weight outcomes?

Abstract

The majority of patients having bariatric surgery are reproductive-age women who are advised to delay pregnancy for at least 12 months after surgery. However many women become pregnant sooner and influence on gestational weight gain (GWG) or long-term weight is unknown. The objective of this study was to compare weight outcomes in pregnancies <12 vs. ≥12 months after bariatric surgery. This is a retrospective cohort study of women with singleton livebirths after bariatric surgery who received care at a single tertiary care center from 2009-2017. GWG was difference in weight at 1st prenatal visit and delivery. GWG adequacy was determined by IOM 2009 guidelines according to prepregnancy BMI (inadequate, adequate, excessive). Postpartum weight retention was calculated as difference between weight at 1st prenatal visit and measured postpartum weight. Weight, maternal and neonatal outcomes were compared between <12 vs. ≥12 months after bariatric surgery with t-tests, Mann-Whitney U and chi-square tests as appropriate. Of 76 pregnancies that met inclusion criteria, 36.8% occurred <12 months (median 7.2) and 63.2% occurred ≥12 months after surgery (median 26.9). There were no significant differences in maternal age, ethnicity or nulliparity between groups, but there were more women with obesity in the <12 group (75% vs. 52%, p=0.03). The <12 group had lower mean GWG (p=0.01) and higher weight loss during pregnancy (p=0.004) compared to the ≥12 group (table). The <12 group had significantly less postpartum weight retention at 6 months compared to the ≥12 group (p=0.02). There were no differences in hyperemesis, hypertensive disorders, gestational diabetes or delivery mode between groups (p>0.05). There were no differences in gestational age at delivery, birth weight and small for gestational age infants between groups (p>0.05). Pregnancy <12 months after bariatric surgery is associated with significantly lower mean GWG and weight loss during pregnancy, but less postpartum weight retention at 6 months. Although there were no differences birthweight, weight loss during pregnancy and its accompanying metabolic changes are concerning for a developing fetus. Further study is needed to determine optimal timing of pregnancy after bariatric surgery with respect to both maternal and infant short and long-term outcomes.