From Bariatric Surgery to Conception: The Ideal Timing to Optimize Fetal Weight.

ABSTRACT

PURPOSE: Bariatric surgery (BS) increases the risk of small for gestational age (SGA) neonates. Guidelines recommend postponing pregnancy for 12-24 months, but optimal surgery-to-conception interval (BSCI) remains uncertain. We aimed to evaluate the impact of BSCI on birth weight and SGA. MATERIALS AND METHODS: Retrospective cohort study of 42 pregnancies following BS, including Roux-en-Y gastric bypass, gastric sleeve, adjustable gastric banding and biliopancreatic diversion. Neonates were classified as SGA if birth weight < 10th percentile. Optimal BSCI was obtained from the analysis of ROC curves, and pregnancies were compared by that cut-off. RESULTS: There was a linear association between BSCI and birth weight and an inverse association with SGA, with each additional month of BSCI translating into additional 4.5 g (95%CI 2.0-7.0) on birth weight and -6% risk of SGA (95%CI 0.90-0.99). We established a cut-off of 24.5 months of BSCI for lower risk of SGA. Pregnancies conceived in the first 24 months had a more than tenfold increased risk of SGA (OR 12.6, 95%CI 2.4-66.0), even when adjusted for maternal age, gestational diabetes and inadequate gestational weight gain. CONCLUSION: BSCI was associated with birth weight and SGA. Our results are in line with the recommendations of BSCI of at least 24 months to reduce the risk of SGA.