Risk assessment for preeclampsia in nulliparous women at 11-13weeks gestational age: prospective evaluation of two algorithms

ObjectiveTo evaluate two algorithms for prediction of preeclampsia in a population of nulliparous women in Norway. DesignProspective screening study. SettingNational Centre for Fetal Medicine in Trondheim, Norway. PopulationFive hundred and forty-one nulliparous women. MethodsThe women were examined between 11(+0) and 13(+6)weeks with interviews for maternal characteristics and measurements of mean arterial pressure, uterine artery pulsatility index, pregnancy-associated plasma protein A and placental growth factor. The First Trimester Screening Program version 2.8 by The Fetal Medicine Foundation (FMF) was compared with the Preeclampsia Predictor TM version 1 revision 2 by Perkin Elmer (PREDICTOR). Main outcome measuresPrediction of preeclampsia requiring delivery before 37weeks, before 42weeks and late preeclampsia (delivery after 34weeks). ResultsThe performance of the two algorithms was similar, but quite poor, for prediction of preeclampsia requiring delivery before 42weeks with an area under the curve of 0.77 (0.67-0.87) and sensitivity 40% (95% CI 19.1-63.9) at a fixed 10% false positive rate for FMF and 0.74 (0.63-0.84) and sensitivity 30% (95% CI 11.9-54.3) at a fixed 10% false positive rate for PREDICTOR. The FMF algorithm for preeclampsia requiring delivery <37weeks had an area under the curve of 0.94 (0.86-1.0) and sensitivity of 80% (95% CI 28.4-99.5) at a 10% fixed false positive rate. ConclusionsFetal Medicine Foundation and PREDICTOR algorithms had similar and only modest performance in predicting preeclampsia. The results indicate that the FMF algorithm is suitable for prediction of preterm preeclampsia.