Metformin treatment in pregnant women with polycystic ovary syndrome—is reduced complication rate mediated by changes in the uteroplacental circulation?

Abstract

To study a possible effect of metformin on the uteroplacental circulation. Forty pregnant women with polycystic ovary syndrome (PCOS) were enrolled in a randomized, double-blind, placebo-controlled trial of metformin (1700 mg/day) during pregnancy. Doppler ultrasound examinations of the uterine arteries were performed at 12, 19, 24, 32 and 36 gestational weeks and of the umbilical artery at 19, 24, 32 and 36 gestational weeks. There was a greater mean bilateral uterine artery pulsatility index (PI) at 12 weeks (1.95 vs. 1.58, P = 0.02), and a greater reduction in mean PI from 12 to 19 weeks (P = 0.03) in metformin-treated women. There were no differences in mean PI values between groups at 19, 24, 32 or 36 gestational weeks. Pregnancy complications, such as preterm delivery before 32 weeks, severe pre-eclampsia or serious postpartum events, occurred only in the placebo group (7 of 22 vs. 0 of 18, P = 0.01). There were no associations between uterine artery Doppler measurements and pregnancy complications. We found no differences between groups in mean umbilical artery PI at 19, 24, 32 or 36 gestational weeks. In this small randomized trial, metformin treatment in pregnancy reduced uterine artery impedance between 12 and 19 weeks of gestation, and this was associated with reduced complication rate. Published by John Wiley & Sons, Ltd.