Background: Although bariatric surgery in women of childbearing age reduces the risks of pregnancy complications associated with maternal obesity, little is known of the effect of gestation on weight loss outcomes. Aim: To study weight loss and pregnancy outcomes after bariatric surgery in women of childbearing age. Design and Methods: We performed a retrospective, observational cohort analysis of women aged 18-45 years in a university teaching hospital. The results shown represent mean±standard deviation where appropriate. Results: A total of 232 women aged 34.0±5.9 years with pre-operative weight 137.7±21.3 kg and body mass index (BMI) 50.6±7.2 kg/m2 underwent bariatric surgery that included 197 (84.9%) gastric bypass, 19 (8.2%) gastric banding, 8 (3.4%) sleevegastrectomy and 8 other procedures. Twenty-one women had 28 pregnancies following bariatric surgery, of which 24 (85.7%) resulted in live births, 3 (10.7%) terminations of pregnancy and 1 (3.6%) spontaneous miscarriage. The pregnancy group was younger compared with the non-pregnancy group (28.0±5.4 vs. 34.6±5.6 years; P<0.001) but well matched for pre-operative weight (136.5±18.5 vs. 137.8±21.6 kg), BMI (49.2±7.4 vs. 50.7±7.2 kg/m2) and bariatric procedure. The interval between bariatric surgery and first pregnancy was a median 11 months. The pregnancy group lost 70.4% of excess weight compared with 70.0% in the non-pregnancy group at median 30 months of follow-up. Conclusion: Pregnancy after bariatric surgery is safe and does not adversely affect weight loss outcomes. © The Author 2013. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved.