Use of metformin to treat pregnant women with polycystic ovary syndrome (PregMet2): a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Women with polycystic ovary syndrome (PCOS) have an increased risk of pregnancy complications. Epi-analysis of two previous randomised controlled trials that compared metformin with placebo during pregnancy in women with PCOS showed a significant reduction in late miscarriages and preterm births in the metformin group. The aim of this third randomised trial (PregMet2) was to test the hypothesis that metformin prevents late miscarriage and preterm birth in women with PCOS. METHODS: PregMet2 was a randomised, placebo-controlled, double-blind, multicentre trial done at 14 hospitals in Norway, Sweden, and Iceland. Singleton pregnant women with PCOS aged 18-45 years were eligible for inclusion. After receiving information about the study at their first antenatal visit or from the internet, women signed up individually to participate in the study. Participants were randomly assigned (1:1) to receive metformin or placebo by computer-generated random numbers. Randomisation was in blocks of ten for each country and centre; the first block had a random size between one and ten to assure masking. Participants were assigned to receive oral metformin 500 mg twice daily or placebo during the first week of treatment, which increased to 1000 mg twice daily or placebo from week 2 until delivery. Placebo tablets and metformin tablets were identical and participants and study personnel were masked to treatment allocation. The primary outcome was the composite incidence of late miscarriage (between week 13 and week 22 and 6 days) and preterm birth (between week 23 and week 36 and 6 days), analysed in the intention-to-treat population. Secondary endpoints included the incidence of gestational diabetes, preeclampsia, pregnancy-induced hypertension, and admission of the neonate to the neonatal intensive care unit. We also did a post-hoc individual participant data analysis of pregnancy outcomes, pooling data from the two previous trials with the present study. The study was registered with ClinicalTrials.gov, number NCT01587378, and EudraCT, number 2011-002203-15. FINDINGS: The study took place between Oct 19, 2012, and Sept 1, 2017. We randomly assigned 487 women to metformin (n=244) or placebo (n=243). In the intention-to-treat analysis, our composite primary outcome of late miscarriage and preterm birth occurred in 12 (5%) of 238 women in the metformin group and 23 (10%) of 240 women in the placebo group (odds ratio [OR] 0·50, 95% CI 0·22-1·08; p=0·08). We found no significant differences for our secondary endpoints, including incidence of gestational diabetes (60 [25%] of 238 women in the metformin group vs 57 [24%] of 240 women in the placebo group; OR 1·09, 95% CI 0·69-1·66; p=0·75). We noted no substantial between-group differences in serious adverse events in either mothers or offspring, and no serious adverse events were considered drug-related by principal investigators. In the post-hoc pooled analysis of individual participant data from the present trial and two previous trials, 18 (5%) of 397 women had late miscarriage or preterm delivery in the metformin group compared with 40 (10%) of 399 women in the placebo group (OR 0·43, 95% CI 0·23-0·79; p=0·004). INTERPRETATION: In pregnant women with PCOS, metformin treatment from the late first trimester until delivery might reduce the risk of late miscarriage and preterm birth, but does not prevent gestational diabetes. FUNDING: Research Council of Norway, Novo Nordisk Foundation, St Olav's University Hospital, and Norwegian University of Science and Technology.

PCOS--what matters in early pregnancy?--data from a cross-sectional, multicenter study.

OBJECTIVE: To describe patient characteristics according to different diagnostic criteria in early pregnancy, in women with polycystic ovary syndrome (PCOS). DESIGN: Descriptive, cross-sectional study of 257 women with PCOS in the first trimester of pregnancy. SETTING: Data from a multicenter trial at the time of inclusion. POPULATION: 257 PCOS women with singleton pregnancies. METHODS: Investigator-administrated questionnaires were filled out. Clinical examination was performed by the investigators. Fasting blood samples were collected. MAIN OUTCOME MEASURES: Biometric data, androgens, glucose and insulin levels. RESULTS: Women who met the National Institutes of Health (NIH) criteria for PCOS had higher body mass index (BMI), testosterone, dehydroepiandrostenedione, free testosterone index (FTI) and insulin levels compared with those who only met the Rotterdam consensus criteria. Adjusted for age and BMI, only testosterone and FTI were higher in those who met the NIH criteria. BMI was a strong, independent predictor of both systolic and diastolic blood pressure in early PCOS pregnancy, while both FTI and fasting insulin were independent predictors of systolic blood pressure. Twenty-two (9%) of the participants had gestational diabetes mellitus in the first trimester of pregnancy. CONCLUSIONS: In the first trimester, PCOS women diagnosed according to NIH criteria were more metabolically and endocrinologically abnormal compared with those who only met the Rotterdam consensus criteria. BMI and FTI were independent predictive factors for blood pressure. There was a high prevalence of gestational diabetes mellitus in early PCOS pregnancies.

Metformin versus placebo from first trimester to delivery in polycystic ovary syndrome: a randomized, controlled multicenter study.

CONTEXT: Metformin is widely prescribed to pregnant women with polycystic ovary syndrome (PCOS) in an attempt to reduce pregnancy complications. Metformin is not approved for this indication, and evidence for this practice is lacking. OBJECTIVES: Our objective was to test the hypothesis that metformin, from first trimester to delivery, reduces pregnancy complications in women with PCOS. DESIGN AND SETTING: We conducted a randomized, placebo-controlled, double-blind, multicenter study at 11 secondary care centers. PARTICIPANTS: The participants were 257 women with PCOS, in the first trimester of pregnancy, aged 18-42 yr. INTERVENTION: We randomly assigned 274 singleton pregnancies (in 257 women) to receive metformin or placebo, from first trimester to delivery. MAIN OUTCOME MEASURES: The prevalence of preeclampsia, gestational diabetes mellitus, preterm delivery, and a composite of these three outcomes is reported. RESULTS: Preeclampsia prevalence was 7.4% in the metformin group and 3.7% in the placebo group (3.7%; 95% CI, -1.7-9.2) (P=0.18). Preterm delivery prevalence was 3.7% in the metformin group and 8.2% in the placebo group (-4.4%; 95%, CI, -10.1-1.2) (P=0.12). Gestational diabetes mellitus prevalence was 17.6% in the metformin group and 16.9% in the placebo group (0.8%; 95% CI, -8.6-10.2) (P=0.87). The composite primary endpoint prevalence was 25.9 and 24.4%, respectively (1.5%; 95% CI, -8.9-11.3) (P=0.78). Women in the metformin group gained less weight during pregnancy compared with those in the placebo group. There was no difference in fetal birth weight between the groups. CONCLUSIONS: Metformin treatment from first trimester to delivery did not reduce pregnancy complications in PCOS.