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

Objectives: 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. Methods: Healthy pregnancy women, referred to our center at or before 32weeks 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⁺⁰weeks 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. Results: 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 (r²=0.7; p<0.05). Conclusion: 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.