Context: Worldwide, metformin is prescribed to improve pregnancy outcome in polycystic ovary syndrome (PCOS). Metformin may also benefit future health by modulating increased metabolic stress during pregnancy.
Objective: To investigate whether metformin during pregnancy modified future metabolic health in women with PCOS.
Design: Follow-up study of a randomized controlled trial that compared metformin with placebo in women with PCOS. Mean follow-up period was 7.7 years (range, 5 to 11 years).
Setting: Three university hospitals, seven local hospitals, and one gynecological specialist practice.
Participants: Women with PCOS according to Rotterdam criteria; all former participants in the Metformin in Pregnant PCOS Women Study.
Intervention: Metformin 2000 mg daily or placebo from first trimester to delivery in the original study. No intervention in the present follow-up study.
Main outcomes and measures: Main outcome measure was weight gain in the follow-up period. Weight, body mass index (BMI), waist and hip circumferences, and blood pressure (BP) were registered. Body composition was assessed by bioelectrical impedance analysis, and fasting lipids, glucose, and insulin were analyzed.
Results: Of 239 invited women, 131 (55%) participated in the follow-up. Weight gain was similar in women given metformin (2.1 ± 10.5 kg) and women given placebo (1.8 ± 11.2 kg) at 7.7 years' follow-up after pregnancy (P = 0.834). No difference was found in BMI, waist/hip ratio, BP, body composition, lipids, glucose and insulin levels, or prevalence of metabolic syndrome at follow-up between those treated with metformin and those treated with placebo during pregnancy.
Conclusion: Metformin treatment during pregnancy did not influence the metabolic profile in women with PCOS at 7.7 years of follow-up.
Trial registration: ClinicalTrials.gov NCT00159536 NCT03259919.