Pregnancy after bariatric surgery in women with rheumatic diseases and association with adverse birth outcomes

Background: Autoimmune rheumatic diseases (ARDs) and bariatric surgery are each risk factors for adverse birth outcomes. To date, no study has investigated their combined impact on birth outcomes. Objectives: The objective of this study was to evaluate the impact of bariatric surgery on pregnancy outcomes in women with an ARD. As a secondary comparison, we assessed the risk of bariatric surgery on the same outcomes in women without an ARD. Setting: Records maintained by the California Office of Statewide Health Planning and Development. Methods: This cohort study included infants born between 20–44 weeks of gestation in California between 2011–2018. Risks of adverse pregnancy outcomes were evaluated for women with a history of bariatric surgery as compared to women without a history of bariatric surgery, stratified by ARD, using log-linear regression with a Poisson distribution. Results: The study included 3,574,165 infants, of whom 10,823 (0.3%) were born to women who had an ARD and 13,529 (0.38%) to women with a history of bariatric surgery. There were 155 infants born to women (0.0043%) with both an ARD and a history of bariatric surgery. In women with an ARD and without bariatric surgery, the prevalence of preterm births was 18%, compared to 17.4% in women with both ARD and bariatric surgery; in women without ARD but with prior bariatric surgery, the prevalence of preterm births was 13.7%, compared to 8.2% in women without bariatric surgery. Except for neonatal intensive care unit (NICU) admissions, women with an ARD and history of bariatric surgery were not at a statistically increased risk of having other adverse pregnancy outcomes as compared to women with an ARD and no history of bariatric surgery. Conclusion: Our study shows that women with ARD already have a high occurrence of several adverse birth outcomes, and this was not further increased by a history of bariatric surgery. The infants born to women with a history of ARD and bariatric surgery were admitted to the NICU significantly more than the infants born to women with an ARD and no history of bariatric surgery.