Gestational Weight Gain in Pregnancies Following Bariatric Surgery.

Introduction: To compare the gestational weight gain (GWG) between women with previous bariatric surgery and those without and investigate whether GWG correlates with birthweight (BW) or delivery of a small-for-gestational-age (SGA) neonate.

Materials And Methods: Prospective, longitudinal study, include 100 pregnant women with previous bariatric surgery and 100 without weight loss surgery, but with similar early-pregnancy body mass index (BMI). In a sub-study, 50 of the post-bariatric women were also matched to 50 women without surgery, but early-pregnancy BMI similar to the pre-surgery BMI of the post-bariatric ones. All women had their weight/BMI measured at 11-14 and 35-37 weeks of gestation, and the difference in maternal weight/BMI between the two time points was expressed as GWG/BMI gain. Associations between maternal GWG/BMI gain and birthweight (BW) were examined.

Results: Compared to no bariatric women with similar early-pregnancy BMI, post-bariatric women had similar GWG (p = 0.46), and the number of women with appropriate, insufficient, and excessive weight gain was comparable between groups (p = 0.76). However, post-bariatric women delivered smaller babies (p < 0.001), and GWG was not a significant predictor of BW or of delivering a SGA neonate. Compared to no bariatric women with similar pre-surgery BMI, post-bariatric ones had higher GWG (p < 0.01) but still delivered smaller neonates (p = 0.001).

Conclusions: Post-bariatric women seem to have similar or greater GWG compared to women without surgery matched for early-pregnancy or pre-surgery BMI, respectively. Maternal GWG was not associated with BW or higher prevalence of SGA neonates seen in women with previous bariatric surgery.