Preeclampsia (PE) is a major obstetric complication with short- and long-term consequences for the mother and the fetus. Early screening tools to reduce its mortality and morbidity, as well as to prevent the life-threatening consequences are needed. Thus, the detection of women at risk of suffering PE is key to apply preventive and treatment strategies. Recently, the maternal contribution to PE based on defective decidualization has been evidenced and new technical approaches developed to detect circulating biomolecules in blood such as RNA fragments. The main objective of this study is to evaluate the diagnostic precision of the molecular profile from the maternal blood analysed for the early screening of early onset preeclampsia (EOPE).

The hypothesis is that there is a unique molecular profile in peripheral blood specific to women who develop EOPE that allow an early assess woman´s risk of developing this pregnancy complication.

The purposed study is a biomedical, prospective, multicentre, case-control aimed to determine the predictive value and diagnostic precision of the maternal blood molecular profile for the early screening of EOPE. Late-onset preeclampsia (LOPE) and other pregnancy complications (such as preterm birth, intrauterine growth restriction, gestational diabetes, placenta previa, placental abruption, placenta accreta, premature rupture of preterm membranes, antepartum fetal death, uterine rupture and previous vasa, among others) could be analysed as a secondary outcome.

Subjects will be 9585 pregnant women recruited between 9 and 14 gestational weeks. Participants will provide peripheral blood sample at three different times during pregnancy to be characterised at molecular level in the iPremom laboratories (Igenomix Preeclampsia SLU) after their obstetric outcome was known.

Once the 50% of the total enrolment is achieved, an interim analysis will be conducted by an independent external committee. Data will be registered in an electronic Case Report Form (eCRF) specifically designed for this study. Monitoring activities and data verification will be performed during the whole study to ensure data quality, integrity and transparency.

The total estimated duration of the study is 30 months, of which the first 18 months will correspond to the recruitment period of the participants.

Inclusion Criteria:

• Patients whose written informed consent approved by the Ethics Committee (EC) has been obtained, after having been duly informed of the nature of the study and voluntarily accepted to participate after being fully aware of the potential risks, benefits and any discomfort involved.
• Women over the age of 18 at the time of signing the informed consent form.
• Pregnant women with single gestation between weeks 9 and 14 of gestation.

Exclusion Criteria:

• Known malignancy
• History of organ transplant or bone marrow transplant.
• Maternal transfusion in the last 8 weeks prior to taking the sample.
• Early gestational loss
• Existence of serious or uncontrolled bacterial, fungal or viral infections that, in the opinion of the investigator may interfere with the patient's participation in the study or the evaluation of the results of the study.
• Other circumstances or difficulties that, in the investigator's opinion, may suppose a risk to the subject or reduce the chances of obtaining satisfactory data to achieve the objectives of the study.

Pregnant women over 18 years old

Pregnant women over the age of 18 recruited between 9 and 14 gestational weeks who attend the participating referral centers for their regular gynecological-obstetric follow-up, as well as their childbirth care.