A clinical study was undertaken to assess gynecologic-obstetric changes in morbidly obese women who lost greater than or equal to 50% of their excess weight with bariatric surgery. The 138 females (109 of reproductive age), age 35 +/- 9 SD yr, weighed 124 +/- 23 kg before surgery and 79 +/- 13 kg after weight loss had stabilized. Menstrual irregularities were present in 40.4% of premenopausal patients preoperatively; after massive weight loss, cycles were abnormal in 4.6% (p less than 0.001). Infertility problems were present preoperatively in 29.3% Of these, nine tried to conceive after weight loss and were successful. During past pregnancies, medical complications were frequent (hypertension 26.7%, pre-eclampsia 12.8%, diabetes 7.0%, and deep vein thrombosis 7.0%). After weight-loss stabilization, these obstetric complications did not occur. Incidence of urinary stress incontinence decreased from 61.2% to 11.6% (p less than 0.001). Gynecologic-obstetric changes tended to normalize after loss of massive body weight.