Gestational Weight Gain in Pregnancies Following Bariatric Surgery

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.

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.

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).

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.