Partial recovery of luteal function after bariatric surgery in obese women

ObjectiveTo determine whether obesity-related reproductive endocrine abnormalities in ovulatory women are reversible with weight loss.DesignObservational cohort study.SettingHealthy volunteers in an academic research environment.Patient(s)Women aged 18–48 years with regular menstrual cycles 21–40 days and a body mass index (BMI) ≥35 kg/m2 planning to undergo bariatric surgery were recruited.Intervention(s)Twenty-five eumenorrheic (non–polycystic ovary syndrome) women with a mean BMI of 47.3 ± 5.2 kg/m2 were sampled with daily menstrual cycle urinary hormones before (n = 25) and 6 months after (n = 9) weight loss surgery resulting in >25% reduction of sinitial body weight. Daily hormones were compared before and after surgery and with 14 normal-weight control subjects.Main Outcome Measure(s)Metabolites of LH, FSH, E2, and P were measured daily for one menstrual cycle. Group means were compared using t tests among ovulatory cycles.Result(s)Luteal pregnanediol glucuronide (Pdg) increased from 32.8 ± 10.9 to 73.7 ± 30.5 μg/mg creatinine (Cr) and whole-cycle LH increased from 168.8 ± 24.2 to 292.1 ± 79.6 mIU/mg Cr after surgically induced weight loss. Luteal Pdg remained lower than in normal-weight control subjects (151.7 ± 111.1 μg/mg Cr). Obese women took longer to attain a postovulatory Pdg rise of >2 μg/mg Cr than control subjects (3.91 ± 1.51 vs. 1.71 ± 1.59 days); this improved after surgery (2.4 ± 1.82 days). Whole-cycle estrone conjugates (E1c) was similar to control subjects at baseline, but decreased after weight loss (from 1,026.7 ± 194.2 to 605.4 ± 167.1 ng/mg Cr). Follicle-stimulating hormone did not relate to body size in this sample.Conclusion(s)Women of very high BMI have deficient luteal LH and Pdg excretion and a delayed ovulatory Pdg rise compared with normal-weight women. Although these parameters improved with weight loss, Pdg did not approach levels seen in normal-weight women. Luteinizing hormone may be less effective in stimulating the corpus luteum in obesity. The large postoperative decrease in E1c may reflect the loss of estrone-producing adipose tissue after weight loss.