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.