SPIRITFirst Trimester Screening for Preeclampsia and Intrauterine Growth RestrIction Using Three Dimensional Doppler Angiography (SPIRIT): A Prospective Study in Nulliparous Pregnant Women

Introduction: Preeclampsia (PE) and intrauterine growth restriction (IUGR) are two major pregnancy complications, related to a chronic utero-placental hypoperfusion. Nowadays, there isn't a screening or diagnostic test in clinic for utero-placental vascularization deficiency. Since 2004, 3D Power Doppler angiography has been used for the evaluation of utero-placental vascularisation and three vascular indices have been calculated: the vascularisation index (VI), flow index (FI) and vascularisation-FI (VFI). A high intra and inter-observer reproducibility and its potential interest for placental function study were reported. The investigator's main hypothesis is that these 3DPD indices could provide predictive values for PE and/or IUGR occurrence much higher than those observed with the currents other markers. Objectives: The main objective of this study is to determine differences in 3DPD indices at first trimester between pregnancies defined at their outcome as uncomplicated pregnancy, PE (mild and severe) and IUGR in nulliparous women. Methods and analysis: This is a prospective study. The investigators expect to include 2200 women in 4 French centers: Centre Hospitalier Universitaire de Nancy, Paris-Port-Royal (Assistance Publique - Hôpitaux de Paris), Strasbourg and Belfort (Hôpital Nord Franche-Comté). The nulliparous pregnant women will be recruited during their 1st trimester consultation for routine Down syndrome screening (11-13+6 gestation weeks). Especially for the study, the 3DPD and Uterine Artery Doppler (UAD) acquisition, which last less than 10 min, will be included in the current routine 11-13+6 gestation weeks ultrasound screening. Also, additional blood samples will be taken for biomarker analysis (PAPP-A and P1GF) and biological collection. Utero-placental vascularization indices (VI, FI, VFI) will be quantified using VOCAL® software. For each subgroup (uncomplicated pregnancy, PE and IUGR) mean values in 3DPD indices will be computed and compared using a pairwise t test with a Bonferroni correction p value adjustment.