- Background Overweight and obesity have been shown to be associated with increased adverse pregnancy outcomes. Weight reduction improves maternal health status and reduces the risk of pregnancy complications, as well as long-term consequences. Our objective was to compare the pregnancy outcomes of the same women who delivered before and after bariatric surgery. Methods A retrospective study comparing pregnancy outcomes, of the same women, delivered before and after a bariatric surgery was conducted. The observed deliveries occurred from 1988 to 2008 at Soroka University Medical Center, the sole tertiary hospital in the southern region of Israel. Results The present study included 288 paired pregnancies: 144 deliveries before and 144 after bariatric surgery. A significant reduction in the prepregnancy and predelivery maternal body mass index was noted after bariatric surgery (36.37 ± 5.2 versus 30.50 ± 5.4 kg/m2, P < .001; and 40.15 ± 4.92 versus 34.41 ± 5.42 kg/m2, P < .001; respectively). Only 8 patients (5.6%) were admitted during their pregnancy for bariatric complications. Pregnancy complications, such as hypertensive disorders (31.9% versus 16.6%; P = .004) and diabetes mellitus (20.8% versus 7.6%; P = .001), were significantly reduced after bariatric surgery. The rate of cesarean deliveries because of labor dystocia was significantly lower after bariatric surgery (5.6% versus 2.1%, P < .05). Using a multiple logistic regression model, controlling for maternal age, the reduction in hypertensive disorders (odds ratio .4, 95% confidence interval .2–.8) and diabetes mellitus (odds ratio .15, 95% confidence interval .1–.4) remained significant. Conclusion A significant decrease in pregnancy complications, such as hypertensive disorders and diabetes mellitus, is achieved after bariatric surgery.