Abstract
Background: Preeclampsia (PE) affects 2 8% of pregnant women and is a leading cause of maternal and perinatal morbidity and mortality. In high risk pregnant women, low dose aspirin (LDA 100 160 mg/day) started before 16 WG reduces the incidence of PE, prematurity, perinatal mortality and low birth weight. First trimester screening of PE allows the identification of a population of pregnant women at high risk of early onset PE and perinatal mortality. It remains unclear whether, on a population scale, the systematic implementation of first trimester screening of PE with treatment of high risk patients by LDA leads to an improvement of maternal and perinatal health.
Methods: This multicenter open randomized controlled trial with two parallel groups will include 14500 pregnant women between 11 14 WG. Eligible women agreeing to participate in the trial will be randomized either to the experimental group with management including screening of PE, or to the control group with usual care without screening of PE. For women in the screening group, the risk of PE will be calculated according to an algorithm combining clinical characteristics, uterine arteries Doppler profile and PlGF concentration. Women with a positive screening test (i.e. predicted risk >1/100) will receive aspirin at 160 mg/day. For women with negative screening, usual pregnancy monitoring without aspirin will be offered. The primary outcome is a composite of severe perinatal morbidity including at least one of the following: perinatal mortality, birth before 34 WG and birth weight < 3rd centile. Secondary endpoints include maternal morbidity and mental health outcomes, and a cost effectiveness evaluation. This study will have a 90% power to show a 50% reduction of the primary outcome in at risk women, expected to represent 10% of the total population in each group, i.e an overall expected 3% frequency of the primary outcome in the intervention group as a whole versus 4% in the control group.
Discussion: This large multicenter randomized trial aims to determine with adequate power if the implementation of first trimester PE screening in all pregnant women would decrease the incidence of perinatal mortality, prematurity before 34 WG and birth weight < 3rd centile.