Impact of Roux-en-Y gastric bypass and sleeve gastrectomy on fetal growth and relationship with maternal nutritional status

Background: There is a lack of evidence on whether sleeve gastrectomy (SG), which induces fewer nutritional deficiencies than Roux-en-Y gastric bypass (RYGB), also affects fetal growth (FG). Objectives: To compare neonatal outcomes after RYGB and SG and to assess the impact of maternal nutritional alterations on FG after both procedures. Setting: University Hospital, France. Methods: Women with singleton pregnancies who had at least 1 nutritional evaluation in our institution between 2004 and 2017 were included. FG was assessed with birth weight (BW) and BW-Z score (adjusted for sex and term), and maternal nutritional deficiencies were defined according to standard and pregnancy-specific norms. Results: During the study period 123 pregnancies were included, 77 after RYGB and 46 after SG. Weight loss was higher after RYGB than after SG (45.6 +/- 12.4 versus 39.5 +/- 13.7 kg, P = .02), but mean weight before pregnancy and weight gain during pregnancy were similar. Mean BW (3026 +/- 677 versus 3162 +/- 712 g), mean BW Z-score and incidence of small for gestational age (24% versus 19%) were not significantly different after RYGB and SG. Mean number of nutritional deficiencies during the second trimester was similar (2.2 +/- 1.5 versus 2.1 +/- 1.2 with specific norms), but the affected parameters differed between procedures. Urinary urea (R = .285, P = .04) was positively correlated to BW Z -score after both procedures. In contrast, serum iron parameters were negatively associated to BW Z -score. Conclusion: FG restriction occurs after both SG and RYGB. FG after bariatric surgery is positively associated with protein supply and negatively correlated with maternal iron status. (C) 2018 Published by Elsevier Inc. on behalf of American Society for Bariatric Surgery.