Effects of gastric bypass surgery on female reproductive function

Context: Reproductive function may improve after bariatric surgery, although the mechanisms and time-related changes are unclear. Objective: The objective of the study was to determine whether ovulation frequency/quality as well as associated reproductive parameters improve after Roux en Y gastric bypass surgery. Design: This was a prospective cohort study that enrolled female subjects from 2005 to 2008 with study visits at baseline and then 1, 3, 6, 12, and up to 24 months after surgery. Setting: The study was conducted at an academic health center. Patients: Twenty-nine obese, reproductive-aged women not using confounding medications participated in the study. Main Outcome Measures: The primary outcome was integrated levels of urinary progestin (pregnanediol 3-glururonide) from daily urinary collections at 12 months postoperatively. Secondary outcomes were changes in vaginal bleeding, other biometric, hormonal, ultrasound, dual-energy x-ray absorptiometry measures, and Female Sexual Function Index. Results: Ninety percent of patients with morbid obesity had ovulatory cycles at baseline, and the ovulatory frequency and luteal phase quality (based on integrated pregnanediol 3-glururonide levels) were not modified by bariatric surgery. The follicular phase was shorter postoperatively [6.5 d shorter at 3 months and 7.9-8.9 d shorter at 6-24 months (P < 0.01)]. Biochemical hyperandrogenism improved, largely due to an immediate postoperative increase in serum SHBG levels(P <0.01), with no change in clinical hyperandrogenism (sebum production, acne, hirsutism). Bone density was preserved, contrasting with a significant loss of lean muscle mass and fat (P < 0.001), reflecting preferential abdominal fat loss (P < 0.001). Female sexual function improved 28% (P =0.02) by 12 months. Conclusions: Ovulation persists despite morbid obesity and the changes from bypass surgery. Reproductive function after surgery is characterized by a shortened follicular phase and improved female sexual function.