Risk of Abdominal Surgery in Pregnancy Among Women Who Have Undergone Bariatric Surgery.

Abstract

To compare the rates of abdominal surgery during pregnancy among women with previous bariatric surgery (women in the case group) and women with first-trimester body mass index (BMI) greater than 35 and no previous bariatric surgery (women in the control group). We conducted a national cohort study, merging data from the Swedish Medical Birth Registry and the Swedish National Patient Registry, comparing women who had bariatric surgery from 1987 to 2011 with women in a control group with first-trimester BMI greater than 35 who had not had bariatric surgery. Primary outcome variables were diagnosis and surgical procedure codes grouped as five outcome categories: 1) intestinal obstruction, 2) gallbladder disease, 3) appendicitis, 4) hernia, and 5) diagnostic laparoscopy or laparotomy without the presence of a diagnosis or surgical code for outcomes in outcome categories 1-4. Odds ratios were computed using multivariate linear regression analysis for each separate pregnancy. For all pregnancies in a given woman, general estimating equations with robust variance estimation were used. Adjustment was made for smoking, year of delivery, maternal age, and previous abdominal surgery. During the first pregnancy after bariatric surgery, the rate of surgery for intestinal obstruction was 1.5% (39/2,543; 95% confidence interval [CI] 1.1-2.0%) in women in the case group compared with 0.02% (4/21,909; 95% CI 0.0-0.04%) among women in the control group (adjusted odds ratio [OR] 34.3, 95% CI 11.9-98.7). Similarly, the rate of diagnostic laparoscopy or laparotomy was 1.5% (37/2,542; 95% CI 1.0-1.9%) among women in the case group compared with 0.1% (18/21,909; 95% CI 0.0-0.1%) among women in the control group (adjusted OR 11.3, 95% CI 6.9-18.5). Bariatric surgery is associated with an increased risk of abdominal surgery during pregnancy.