Pregnancy outcome of patients following bariatric surgery as compared with obese women: A population-based study

Objective: To evaluate pregnancy outcome and rates of anemia in patients following bariatric operation in comparison with obese pregnant women. Methods: A retrospective population-based study comparing pregnancy outcome of patients following bariatric with the obese population was conducted. Multivariate logistic regression models were constructed to control for confounders. To evaluate the change in hemoglobin levels, we included women who had one pregnancy before the bariatric surgery and one following the surgery or two pregnancies for women with obesity. Results: This study included 326 women who had one pregnancy before and after a bariatric surgery and 1612 obese women who had at least two consecutive deliveries. Using a multivariable logistic regression model, controlling for confounders such as maternal age, patients following bariatric surgery had lower rates of gestational diabetes mellitus (OR 0.7; 95% CI 0.5-0.9; p=0.49) and macrosomia (OR 0.3; 95% CI 0.2-0.5; p<0.001) as compared with obese parturients. Women post bariatric surgery were more likely to be anemic (hemoglobin<10g/dL) as compared to obese parturients (48% versus 37%; OR, 1.5; 95% CI, 1.2-1.9; p<0.001). A significant decline in hemoglobin level was noted in patients following bariatric surgery (a decline of 0.33g/dL versus 0.18g/dL between two consecutive pregnancies of obese women). Using another multivariable model with anemia as the outcome variable, bariatric was noted as a risk factor for anemia (adjusted OR=1.45, 95%CI 1.13-1.86, p=0.004). Conclusion: Women following bariatric surgery have lower risk for gestational diabetes mellitus and fetal macrosomia as compared with obese parturients. Nevertheless, bariatric surgery is a risk factor for anemia.