The impact of bariatric surgery on pregnancy complication rates

Obesity is associated with multiple pregnancy-related complications. Bariatric surgery is frequently performed in women of childbearing age. While the impact of bariatric surgery on fertility and nutritional complications has been characterized, few studies on effects of bariatric surgery on obesity-related pregnancy complications exist. The purpose of this study is to examine the impact of bariatric surgery on pregnancy complications in a US insured population.

Pregnancy-related claims from 2011-2019 were obtained from MarketScan commercial claims database for bariatric surgical patients and non-surgical patients with no history of obesity. Claims were grouped into 3 time periods: pre-surgery (time of first claim to date of surgery), peri-surgery (date of surgery to 24 month postoperatively), and post-surgery (> 24 month postoperatively). Peri-surgery period was defined based on the recommendation to avoid pregnancy for the first 12-24 months following surgery. Codes for both maternal and fetal pregnancy-related complications were extracted from the database. Standardized incidence rates in person-months (pms) were calculated and generalized estimating equations with Poisson distribution tested for differences in each category at the three time intervals.

The final cohort included 163612 female bariatric surgery patients. The rate of successful births was 3/1000 pms in the pre-surgery and peri-surgery period and increased to 4/1000 pms in the post-surgery period, compared to a rate of 7/1000 in the control group. The rate of pregnancy complications in the pre-surgery group was 4/1000 pms and dropped to 2/1000 pms in the peri- and post-surgery periods. The complication rate in the control group was 4/1000 pms.

After bariatric surgery, the rate of pregnancy complications is lower than non-obese, non-bariatric surgery patients. Compared to before surgery, pregnancy complications decrease by 63% in the peri-surgery period and 57% in the post-surgery period. In the US, bariatric surgery is an important intervention for decreasing pregnancy complications in patients with obesity.