Maternal body mass index influences umbilical artery Doppler velocimetry in physiologic pregnancies

The aim of our study was to assess whether there is a relationship between maternal body mass index (BMI) and umbilical artery Doppler velocimetry in physiologic pregnancies.

Healthy pregnancy women, referred to our center at or before 32 weeks of gestation, were recruited. According to BMI, they were divided into underweight (BMI < 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9) and obese women (BMI ≥ 30). At 32(+0)  weeks of gestation, maternal BMI and umbilical artery Doppler velocimetry were recorded. A correlation between pulsatility index of umbilical artery and BMI was assessed by one-way ANOVA test, multiple comparison test (Bonferroni correction) and polynomial regression.

One hundred eighty-five women were included. Mean pulsatility index of umbilical artery at 32(+0) was significantly higher in obese women (0.95 ± 0.01 vs 0.87 ± 0.01 vs 0.67 ± 0.01; p < 0.05). We found a positive correlation between Pulsatility Index of Umbilical Artery and maternal BMI (r(2)  = 0.7; p < 0.05).

There is a positive correlation between BMI and pulsatility index of umbilical artery. These findings suggest that obesity has a negative effect on feto-placetal vessels. If our data will be confirmed, maternal BMI should be considered in evaluation of umbilical Doppler velocimetry.