The prevalence of obesity, defined as a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 30 or higher, among women of reproductive age has increased globally, posing a risk for adverse maternal and fetal outcomes.1 Bariatric surgery is currently the most effective treatment for obesity, with gastric bypass and sleeve gastrectomy being the most common procedures2. Previous studies3-6 have found that women with a history of bariatric surgery, compared with those without such a history but otherwise similar pre surgery characteristics, had lower risk of gestational diabetes, preeclampsia, large-for-gestational age (LGA) birth, and cesarean delivery, whereas the risks of small-for-gestational age (SGA) and preterm birth were higher.
Pregnancy weight gain is associated with all these aforementioned outcomes7-12 and may also influence the association of bariatric surgery with adverse outcomes. However, the association of bariatric surgery with postoperative pregnancy weight gain is not well established. Although most existing studies13-18 report lower pregnancy weight gain after bariatric surgery, many are limited by a small sample size and varying control groups and surgical procedures and do not consider the impact of pre pregnancy BMI or gestational age (eg, a shorter pregnancy time provides less chance of gaining more weight). Furthermore, the impact of time and/or weight loss between the bariatric surgery and conception on postoperative pregnancy weight gain is unclear.19 This Swedish nationwide study compares pregnancy weight gain among women with a history of bariatric surgery vs those without and investigates whether pregnancy weight gain after bariatric surgery differs by surgical procedure, surgery-to-conception interval, and/or surgery-to-conception weight loss.
