EP17.63: Association between body mass index and mean uterine artery pulsatility index >95th percentile in first trimester singleton pregnancies screening

To determine whether there is an association between body mass index and uterine artery pulsatility index greater than 95th percentile (IPAUt >P95) in first trimester screening in singleton pregnancies. Cross-sectional study between 2018 and 2023 at two obstetric ultrasound centres. Ultrasounds were performed by obstetricians endorsed by the Fetal Medicine Foundation. Patients with first trimester screening were included. For BMI, the classification proposed by Atalah was used. The cut-off point for the 95th percentile was 2.42. Analysis was performed according to the nature of the variables. A Chi-square test was used to determine a possible association, considering p < 0.05 as significant 1899 patients were evaluated, of whom 1313 (69.1%) met the inclusion criteria. The mean maternal age was 33.5 ± 4.6 years, and gestational age was 12.0 ± 0.4 weeks. 3.3% (43/1313) patients were categorised as underweight, 60.1% (790/1313) as healthy, 6% (78/1313) as overweight and 30.6% (402/1313) as obese. A statistically significant association was found between the healthy BMI group and having an IPAUt >P95 (p: 0.03). In our experience, there is no statistically significant association between BMI and IPAUt changes in the overweight and obese population. It is noteworthy that this BMI classification is a risk factor for developing pre-eclampsia.