New Blood Test Predicts Preeclampsia With 80% Accuracy

By LabMedica International staff writers
Posted on 14 Feb 2025

Image: The preeclampsia test uses cell-free DNA shed from the placenta during pregnancy (Photo courtesy of 123RF)

Preeclampsia is a pregnancy complication marked by high blood pressure (hypertension) and/or organ dysfunction. It usually develops during the third trimester. The exact cause of preeclampsia remains unclear, but it is believed to involve an abnormal interaction between the placenta and the mother's blood vessels. Traditionally, doctors assess a pregnant woman’s risk based on her medical history. Risk factors for preeclampsia include being a first-time mother, having a history of preeclampsia, hypertension, or chronic kidney disease, or a combination of these. However, preeclampsia can sometimes occur even when none of these conditions are present. For over two decades, researchers have known that the placenta releases DNA into the maternal bloodstream. Laboratories have been able to extract this cell-free DNA, sequence it, and use it to screen for fetal abnormalities like Down syndrome. Now, a new test has been developed that uses cell-free DNA from the placenta during pregnancy to predict preterm preeclampsia with 80% accuracy.

Researchers from UW Medicine (Seattle, WA, USA) and Fred Hutch Cancer Center (Seattle, WA, USA) collaborated on the idea of using cell-free DNA sequencing to screen for preeclampsia. The team used data from tests conducted at UW Medicine over the past two years, where they extracted and sequenced cell-free DNA to screen for fetal abnormalities. These samples, collected between 2017 and 2023, were part of a broader effort to develop a liquid biopsy. The researchers used data from over 1,000 pregnant individuals, starting from the first trimester, to develop and validate their test.

In a study published in Nature Medicine, the researchers found that their method, which analyzes signals contained in circulating cell-free DNA sequence data, had an 80% sensitivity in predicting whether a pregnant individual would develop preterm preeclampsia. Their next steps involve improving the training model with more data and ultimately conducting a trial involving thousands of patients. The researchers envision that this test could become a vital early prediction tool for preeclampsia, seamlessly integrated into routine early pregnancy screenings.

“Although using liquid biopsies for human diseases is largely used in the cancer area, given the frequency at which cell-free DNA screening is performed, prenatal biology truly has incredible opportunities for the discovery and application of innovative tools,” said Dr. Swati Shree, a UW Medicine OB-GYN and co-corresponding author of the paper.

Related Links:
UW Medicine
Fred Hutch Cancer Center