On the potential of metformin to prevent preterm delivery in women with polycystic ovary syndrome - an epi-analysis.

Our aim was to re-evaluate whether metformin may reduce late miscarriage/preterm delivery, pre-eclampsia and gestational diabetes in women with polycystic ovary syndrome (PCOS). We performed an epi-analysis of two randomized controlled trials. The participants were 313 women aged 18-42 years with PCOS who had singleton pregnancies. They were randomized to metformin or placebo treatment from first trimester until delivery. We analysed the prevalence of late miscarriage/preterm delivery, pre-eclampsia and gestational diabetes according to both the intention-to-treat principle and per protocol analysis. The metformin-treated patients had less late miscarriage/preterm delivery; five (3%) vs. 18 (11%) in the placebo group (p < 0.01). There was no difference in the prevalence of gestational diabetes and pre-eclampsia between the metformin and the placebo group. In this epi-analysis, metformin treatment during pregnancy seems to reduce early delivery in women with PCOS. We believe that further randomized studies should be performed before firm conclusions can be drawn.