Innovative Blood Test Identifies Preeclampsia Risk Early in Pregnancy

A recent study presented at the 41st Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE) reveals that a novel blood test can detect the risk of preeclampsia in pregnant women as early as the first trimester, potentially up to five months before clinical symptoms appear. This groundbreaking research, led by Dr. Nerea Castillo Marco from the Carlos Simon Foundation, involved a cohort of 9,586 pregnant women across 14 hospitals in Spain from September 2021 to June 2024.

Preeclampsia, a serious pregnancy complication characterized by high blood pressure and organ damage, poses significant risks to both mothers and infants. Current screening methods often fail to identify more than half of potential cases, typically relying on maternal risk factors or placental biomarkers that only indicate issues once the condition is already developing. The new approach uses cell-free RNA (cfRNA) extracted from maternal plasma, enabling the detection of subtle molecular changes well ahead of symptom onset.

According to the study, the cfRNA model demonstrated impressive predictive capabilities, achieving 83% sensitivity and 90% specificity for early-onset preeclampsia (EOPE), with an area under the curve (AUC) of 0.88. This model successfully predicted EOPE on average 18 weeks prior to clinical diagnosis. Dr. Castillo Marco emphasized the significance of these findings: "For the first time, we've shown that a routine blood sample in the first trimester can give an early warning of preeclampsia with high accuracy, well before symptoms appear. Identifying high-risk pregnancies this early opens a crucial window for preventive treatment and closer monitoring to protect mothers and babies."

In contrast, the study also identified distinct cfRNA signatures for late-onset preeclampsia (LOPE), allowing predictions on average 14.9 weeks before symptoms emerged. While EOPE signatures were linked to changes in the maternal endometrium, LOPE signatures exhibited a different biological profile, suggesting that the two forms of preeclampsia are not only temporally but also biologically distinct. This distinction reinforces the need for tailored approaches in prenatal care.

Dr. Tamara Garrido, the project leader, stated that they are currently conducting a prospective clinical study to validate the cfRNA screening's utility and feasibility within standard prenatal care. "With validation and regulatory efforts already underway, we anticipate that cfRNA-based screening could become available in clinical practice within the next year, offering an unprecedented opportunity for early, non-invasive identification of high-risk pregnancies and timely intervention."

Prof. Dr. Karen Sermon, Chair of ESHRE, acknowledged the study's potential to revolutionize prenatal care, remarking, "Besides offering a major breakthrough in preventive prenatal care for a common and often dangerous condition during pregnancy, this research increases our understanding at a molecular level of a complex pathology that remains poorly understood."

The implications of this research are profound, as early identification of preeclampsia could lead to improved maternal and fetal outcomes through timely interventions. As the medical community anticipates the integration of cfRNA screening into regular prenatal practices, the hope remains that such innovations will significantly reduce the incidence of preeclampsia and its associated complications worldwide.

This study, titled "Maternal plasma cell-free RNA as a liquid biopsy for first-trimester screening of early and late-onset preeclampsia," is currently under review for publication in Nature Communications and has been documented in the journal Human Reproduction (2025). For further details, the research can be accessed via Research Square.