Becoming pregnant within the first year after bariatric surgery adversely affects postoperative weight loss

Approximately 80% of the patients undergoing bariatric surgery are female, with half of them undergoing surgery during their reproductive years. Most guidelines recommend that women wait at least 12 months after surgery before becoming pregnant. No previous studies have investigated whether becoming pregnant in the first or second year after surgery affects weight loss. The aim of this study was to assess whether pregnancy within the first or second year after bariatric surgery affects weight loss up to 5 years after surgery. A single institution. This study is a retrospective study of women who underwent primary bariatric surgery between 2012 and 2016. Weight outcomes were measured until 5 years after surgery. A linear mixed model was used to assess the effect of the time between surgery and conception in groups on the basis of percentage total weight loss. A total of 55 patients undergoing a primary bariatric procedure were included. Forty-seven women underwent a laparoscopic Roux-en-Y gastric bypass (85.5%), and 8 underwent a sleeve gastrectomy (14.5%). The median time between surgery and estimated conception was 22 months (range: 0–51 months). Women who became pregnant between 12 and 24 months after bariatric surgery (n = 18) and women who became pregnant after 24 months (n = 24) had significantly more weight (β = 3.95, P = .020, and β = 4.09, P =.024, respectively) than women who became pregnant within 12 months after bariatric surgery (n = 12). Our results suggest that pregnancy within 12 months after bariatric surgery negatively affects the long-term weight loss after bariatric surgery. •No previous studies have investigated the effect of the timing of a pregnancy after bariatric surgery on weight outcomes•These results suggest that a pregnancy within the first year after bariatric surgery adversely affects postoperative weight loss•The effect of an early pregnancy after bariatric surgery on long-term weight loss may be a reason to discourage women to become pregnant in the first year after surgery