Screening for term preeclampsia at 35 to 37 weeks of gestation – a single center experience

Introduction: Prevention of preeclampsia has short- and long-term benefits for maternal health. Recent data suggests, that combined screening at 35 to 37 weeks of gestation with anamnestic risk factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI) and angiogenic profile (sFlt-1/PlGF) detects up to 80% of all tPE. The aim of this retrospective analysis is to test the performance of third trimester screening for tPE in a single center in Switzerland. Methods: Singleton pregnancies with complete background risk assessments, MAP and if available UtA-PI and sFlt-1/PlGF from 2018 to 2023 were included and risks were calculated on the FMF London website. Results: 1,121 pregnancies, including 22 (2.0%) with tPE were analysed. Median MAP-MoM [IQR] in tPE was 1.08 [1.00-1.14], compared to 0.98 [0.92-1.04] in controls (p<0.0001). Median UtA-PI-MoM [IQR] in tPE was 1.04 [0.85-1.27] versus 0.99 [0.82-1.15] (p=0.56). No sFlt-1/PlGF recordings in tPE were available for analysis. The detection rate in combined screening was 15/22 (68.2%) compared to screening by anamnestic risk factors only of 9/22 (40.9%). Conclusion: This analysis shows that combined screening at 35-37 weeks of gestation including anamnestic risk factors and MAP performs better than screening by anamnestic risk factors alone. These results should further be verified in a prospective trial including all markers.