Pregnancy characteristics and outcomes after bariatric surgery: national-level analysis in the United States

Bariatric surgery is an effective surgical treatment for weight reduction in individuals with obesity. Pregnancy outcomes related to prior bariatric surgery are currently under active investigation.

To assess national-level trends, characteristics, and outcomes of pregnancy after bariatric surgery in the United States.

Retrospective cohort study queried the National Inpatient Sample.

The study population was 14,648,135 patients who had vaginal or cesarean delivery from January 2016 to December 2019. Exposure allocation was based on the history of bariatric surgery. The main outcomes were (1) trends and characteristics related to bariatric surgery, assessed with multivariable binary logistic regression model; and (2) Centers for Disease Control and Prevention-defined severe maternal morbidity, assessed by propensity score matching and generalized estimating equation.

A total of 53,950 (.4%) patients had prior bariatric surgery. The number of patients with prior bariatric surgery increased from .3% to .5%, and this trend remained independent in multivariable analysis (P < .001). Patients who had bariatric surgery were also more likely to be older and have obesity, medical co-morbidities, fetal growth restriction, preterm birth, and cesarean delivery compared with those without bariatric surgery (all, P < .05). In a propensity score matched model, patients who had bariatric surgery were more likely to receive blood product transfusion (2.3% versus 1.6%; odds ratio = 1.45; 95% confidence interval, 1.19-1.77), but severe maternal morbidity other than blood product transfusion was comparable to those without (1.1% versus 1.4%; odds ratio = .80; 95% confidence interval, .63-1.02).

There is a gradual increase of pregnancy after bariatric surgery in recent years in the United States.