Effect of Weight Loss on Menstrual Function in Adolescents with Polycystic Ovary Syndrome

Study Objective: To compare the effects of a hypocaloric low-fat diet with those of a very low carbohydrate diet on body mass index (BMI), waist circumference (WC), and menstrual function in overweight adolescent females with polycystic ovary syndrome (PCOS). Design: Randomized pilot trial of two diets in a prospective, 12-week study. Setting: A hospital-based, academic adolescent medicine division. Participants: 24 females, age 12-22 years (mean 15.8 ± 2.2), with PCOS and a BMI above the 85^th percentile for age (mean 35.7 ± 6.0 kg/m²). Interventions: Nutrition counseling was given biweekly, and dietary compliance, menstrual history, and weight were recorded. WC was measured at the beginning and end of the study. Main Outcome Measures: Changes in weight, BMI, WC, and improvement in menstrual function over the course of the study period. Results: 16 participants completed the study. 12 completers menstruated during the study period, 8 with regularity. The number of periods over 3 months increased from 0.6 ± 0.6 pre-treatment to 1.6 ± 1.3 post-treatment (P = 0.003). Overall, weight loss averaged 6.5% (P < 0.0001) and the WC decreased by an average of 5.7 ± 7.7 cm (P = 0.01). Those who lost weight were 3.4 times more likely to have improved menstrual function (P = 0.001). There were no statistically significant differences between the two groups. Conclusions: Weight loss is feasible in adolescents with PCOS and results in significant improvements in BMI, WC, and menstrual function. Weight management may be preferable as first-line treatment in adolescents, because it targets both the menstrual dysfunction and risk factors for long-term morbidity associated with PCOS.