PP114. First trimester multi-parameter prediction of pre-eclampsia

Pre-eclampsia (PE), which affects about 3-5% of pregnant women, is the most frequent serious medical complication in pregnancy and a major cause of maternal and perinatal morbidity and mortality. During the past three decades, numerous clinical, biophysical, and biochemical screening tests have been proposed for the early detection of PE. Literature shows large variations in the sensitivity and predictive value of these tests. No single screening test used for PE prediction has gained widespread acceptance into clinical practice. Instead, panels of tests, which combine several clinical measurements, seem to be of more value for increasing the predictive value for PE.

The aim of this study was to examine a combination of maternal risk factors, mean arterial blood pressure, and uterine artery Doppler for pre-eclampsia prediction during the first trimester of pregnancy.

Prospective study with singleton pregnancies examined at 11-14 weeks of gestation, presenting consecutively for antenatal care in a tertiary Brazilian hospital. The base-cohort population was 487 singleton pregnancies, including nine case subjects who developed PE requiring delivery before 34 weeks (early PE) and 22 with late PE, 47 with gestational hypertension, and 409 cases subjects (84%) who were unaffected by PE or gestational hypertension. Maternal history, body mass index (BMI), mean arterial pressure (MAP), and uterine artery pulsatility index were recorded in all of the cases. Univariate and logistic regression analysis was used to derive algorithms for the prediction of hypertensive disorders.

The maternal characteristics selected by regression analysis to be part of the final predictive model were nulliparity, previous personal and family history of PE. MAP was higher (86 versus 78 mmHg) in patients who developed PE (p<0.01). The uterine artery percentile of mean PI was higher in the PE than in the control group (50.3%±31.7% versus 37.4%±30.0%; p<0.01). It was estimated that, with the algorithm for PE, 78%, 45%, and 26% of early PE, late PE, and gestational hypertension, respectively, could be detected with a 10% false-positive rate.

The traditional approach to screening for PE, which is based on maternal demographic characteristics and medical history, identifies ∼60% of cases destined to develop early PE for a false-positive rate of 10%. This study proposes that a combination of maternal risk factors, mean arterial blood pressure, and uterine artery Doppler, for the same false-positive rate of 10%, could identify 78% of cases of early PE.