Accuracy of second trimester prediction of preterm preeclampsia by three different screening algorithms.

Aim: To compare the performance of three different screening methods (National Institute for Health and Clinical Excellence (NICE) guidelines, American College of Obstetricians and Gynecologists (ACOG) recommendations and Fetal Medicine Foundation (FMF) algorithm) for second trimester prediction of preeclampsia.

Methods: This was a prospective non-intervention study in singleton pregnancies, including women attending for second trimester morphologic ultrasound at 19-22 weeks. Maternal characteristics, medical history, mean arterial pressure and mean uterine artery Doppler pulsatility index were recorded and used for risk assessment. Outcomes measured were preeclampsia with delivery before 34, before 37 and after 37 weeks gestation. Detection rates, false positive rates and positive likelihood ratios were calculated, and receiver operating characteristic curves were produced.

Results: We screened 543 women during the study. The incidence of preeclampsia before 34, before 37 and after 37 weeks was 0.5, 1.4 and 3.4%, respectively. Detection rates for prediction of preterm preeclampsia were 75% (95% CI 34.9-96.8), 87% (95% CI 47.3-99.6), 100% (95% CI 63.0-100) and 100% (95% CI 63.0-100) for NICE guidelines, ACOG recommendations, FMF algorithm with a 1:100 cut-off and FMF algorithm at 1:60 cut-off, respectively. False positive rates were, 22, 67, 19 and 12% for NICE guidelines, ACOG recommendations, FMF algorithm with a 1:100 cut-off and FMF algorithm at 1:60 cut-off, respectively.

Conclusion: Second trimester combined screening for preterm preeclampsia by maternal history, mean arterial pressure and mean uterine artery Doppler pulsatility index (FMF algorithm) was superior to screening by maternal factors alone (NICE guidelines and ACOG recommendations).