Do low-risk nulliparous women with abnormal uterine artery Doppler in the third trimester have poorer perinatal outcomes? A longitudinal prospective study on uterine artery Doppler in low-risk nulliparous women and correlation with pregnancy outcomes.

OBJECTIVE

To evaluate uterine artery (UtA) Doppler over the course of pregnancy in low-risk nulliparous women and to analyze whether an abnormal uterine artery pulsatility index (UtA-PI) at a 32-34 week' scan implies poorer perinatal outcomes.

METHODS

An observational prospective study was carried out including 616 low-risk nulliparous women. Women with any of the following were excluded: fetal abnormalities, multiple pregnancy, and heparin, metformin or hypotensive treatment. Maternal characteristics, mean arterial pressure measurements and UtA Doppler findings were recorded longitudinally.

RESULTS

Complete pregnancy data were available for 489/616 women (79.3%). Of these, 385 women had a normal UtA-PI throughout pregnancy (Group 0), while 50 (10.1%) had an UtA-PI > 95th percentile in the first or the second trimester that normalized in the third trimester (Group 1), and 56 (11.4%) had an abnormal UtA-PI in the third trimester (Group 2). We found that the rate of pre-eclampsia (PE) was higher in Group 2 (7/56 versus 4/435, p = 0.003) as was the rate of intrauterine growth restriction (IUGR) (6/56 versus 14/435, p = 0.02).

CONCLUSIONS

Low-risk nulliparous women with abnormal UtA Doppler findings in the third trimester are at a higher risk of developing PE and having a baby with IUGR.