Pregnancy outcomes following different types of bariatric surgery: A national cohort study.

Objective: To assess the impact of type of bariatric surgery on pregnancy outcomes.

Study Design: This is a national prospective observational study using the UK Obstetric Surveillance System (UKOSS). Data collection was undertaken in 200 consultant-led NHS maternity units between November 2011 and October 2012 (gastric banding), and April 2014 and March 2016 (gastric bypass and sleeve gastrectomy). Participants were pregnant women following gastric banding (n = 127), gastric bypass (n = 134) and sleeve gastrectomy (n = 29). Maternal and perinatal outcomes were compared using generalised linear and linear mixed models. Maternal outcomes included gestational weight gain, pre-eclampsia, gestational diabetes, anaemia, surgical complications. Perinatal outcomes included birthweight, small/large for gestational age (SGA/LGA), preterm birth, stillbirth.

Results: Maternal: Women pregnant after gastric banding and sleeve gastrectomy had a lower risk of anaemia compared with gastric bypass (banding (16 %) vs bypass (39 %): p = 0.002, sleeve (21 %) vs bypass: p = 0.04). Gestational diabetes risk was lower after gastric banding compared with gastric bypass (7 % vs 16 %, p = 0.03) despite women with banding having significantly greater weight at booking as well as gestational weight gain. Women pregnant after gastric banding and sleeve gastrectomy had a lower risk of surgical complications than after gastric bypass (banding (0.9 %) vs bypass (11.4 %): p = 0.03, sleeve (0.0 %) vs bypass: p = 0.06). Perinatal: Infants born to mothers after gastric banding had a higher birthweight than those born to mothers after gastric bypass (mean difference = 260 g (125-395), p < 0.001). Infants were more likely to be LGA if their mothers had gastric banding compared with gastric bypass or sleeve gastrectomy (banding (21 %) vs bypass (5 %): p = 0.006; banding vs sleeve (3 %): p = 0.03). Risk of preterm birth was higher in women with gastric banding compared with gastric bypass (13 % vs 8 %, p = 0.04).

Conclusions: Women planning bariatric surgery should be counselled regarding the differing impacts of different types of procedure on any future pregnancy. Pre-existing gastric bypass is associated with higher rates of potentially serious surgical complications during pregnancy.