Uterine artery doppler in pregnancy: women with PCOS compared to healthy controls

Abstract

Polycystic ovary syndrome (PCOS) is linked to several pregnancy complications, such as GDM, preterm delivery and preeclampsia. Increased resistance in the uterine artery, measured as pulsatility index, results in decreased blood flow to the placenta and fetus and is often an early sign of placenta pathology and/or hypertensive disorder in pregnancy. Doppler ultrasound is a frequently used method for risk evaluation during pregnancy. Former studies on women with PCOS are few and report a decreased blood flow in the uterine artery in both nonpregnant and pregnant women. In the current study we investigated: 1) whether there was a difference in uterine artery pulsatility index (UtAPI) in pregnant PCOS women versus healthy controls and 2) whether there was an immediate effect of metformin on blood flow in PCOS women. The present study was a sub-study of an RCT (The PregMet study). It was conducted at one tertiary centre, 48 pregnant women with PCOS and 119 healthy controls participated. The women with PCOS were randomly assigned to metformin (1000 mg x 2 daily) or placebo. UtAPI was measured twice in the 1 s t trimester and twice in the 2nd trimester. There was no difference in UtAPI between the PCOS women and the healthy controls at any time point. P-values ranged between 0.34 and 0.77. We found no difference in UtAPI between the metformin and placebo groups two hours after intake of study medication (500 mg metformin or placebo) and a meal. Surprisingly, we found that both metformin and placebo treated PCOS women had significantly higher UtAPI two hours after intake of a meal compared to fasting state, P=0.02. Contrary to former studies we did not find altered UtAPI (uterine blood flow) in pregnant women with PCOS compared to healthy controls. There was no immediate effect of metformin. This was the first study which showed that fasting vs. non-fasting state in the same women resulted in significant changes in blood flow of the uterine artery. Further studies are needed to clarify if standardization of food intake before Doppler examinations should be considered when interpreting the results of UtAPI measurements.