Mirvie’s blood test predicts preeclampsia risk early in pregnancy

Mirvie’s blood test predicts preeclampsia risk early in pregnancy | Image Credit: © Svitlana - © Svitlana - stock.adobe.com.

Early prediction of hypertensive disorders in pregnancy

A simple blood test may allow the risk of hypertensive disorders of pregnancy (HDPs) such as preeclampsia to be predicted months before symptoms, according to a recent study published in Nature Communications.¹

Over 9000 pregnancies from the multi-center Miracle of Life prospective study were included in the analysis, which identified RNA signatures that may be used to differentiate between severe and mild HDPs. The data provided validation for Mirvie’s simple blood test for preeclampsia prediction at 17.5- to 22-weeks’ gestation.¹

“By the time a patient is symptomatic, it’s a race against the clock to try to get the baby to term and not risk the mother’s health,” said Kara Rood, MD, maternal-fetal medicine physician. “Current guidelines are not helping us identify which patients are truly at high risk and we need better tools.”¹

According to Rood, Mirvie’s test allows for improved risk prediction, which leads to informed women and care teams and lets action be made to delay or prevent disease onset. Additionally, the test may be performed in pregnancies without pre-existing high-risk conditions.¹

Participant recruitment and sample collection

Study participants were recruited directly or from 1 of 11 US medical centers.² Standard non-fasting venipuncture was utilized to obtain whole blood samples, which were shipped to the Mirvie laboratory at ambient temperatures overnight. The same protocol was used to obtain samples from non-pregnant controls.

Collection was performed from 17 weeks and 4 days to 22 weeks and 0 days of gestation, which coincided with prenatal care for a fetal anomaly scan. Medical records were assessed for relevant clinical data, with trained clinicians performing clinical monitoring. This data was only made available on a need-to-know basis.²

A reverse transcription-quantitative polymerase chain reaction assay was used to assess the quality of cell-free RNA samples and libraries. Investigators compared placental-associated HDP with immune-associated HDP to identify differentially expressed genes.²

There were 9102 individuals included in the final analysis, with the first 62% of samples allocated to training and the final 38% to validation. Of these patients, 4402 and 2243, respectively, did not have a high-risk factor for HDP.²

Key genetic markers identified

PAPPA2, highly expressed in the placenta, and CD163, highly expressed in immune cells, were the 2 genes with the most significant effect size for HDPs. This data is support by prior research indicating impacts on preeclampsia from the placental and immune pathways.²

Eight clinical subgroups for HDP severity were developed. These were based on criteria including gestational age at preeclampsia diagnosis, gestational age at delivery, and presence of severe features. All 3 of these factorswere significantly dose-dependent to PAPPA2.²

Molecular subtypes of HDP identified

When evaluating the impact of PAPPA2 and CD163 expression across the 8 subgroups, 2 distinct molecular subtypes were identified. The first was matched to groups 1 through 3, which had the most severe clinical outcomes. The second was matched to the remaining subgroups with reduced effect sizes for PAPPA2.²

Subgroups 1 through 3 had a 5.7-fold increased effect size compared to non-HDP patients. This indicated strong placental involvement among these subgroups. However, CD163 had similar expression across all 8 subgroups. The effect size for CD163 was higher than PAPPA2 in subgroups 4 through 8, indicating immune origin among these patients.²

Implications for risk classification

Based on this data, investigators classified 2 distinct molecular subtypes for HDP. The first included subgroups 1 through 3, who were diagnosed before 37-weeks’ gestation. The second included subgroups 4 through 8, who had most term preeclampsia, postpartum preeclampsia, and GHTN.²

“Mirvie’s preeclampsia risk prediction test can now improve risk assessment, helping women and their care teams be informed and take actions with the potential to delay onset or prevent the disease,” said Rood.¹

Reference

1. Mirvie announces results from largest molecular study in pregnancy and clinical validation of simple blood test to predict risk for preeclampsia months before symptoms. Mirvie. April 8, 2025. Accessed April 10, 2025. https://www.eurekalert.org/news-releases/1079392.
2. Elovitz MA, Gee EPS, Delaney-Busch N, et al. Molecular subtyping of hypertensive disorders of pregnancy. Nature Communication. 2025;16. doi:10.1038/s41467-025-58157-y