Blood Test Predicts Pregnancy Due Date

A small study based on circulating RNA in the blood of moms-to-be describes a technique that could be used to help predict who’s most at risk of preterm labor.

In a study of 31 expectant mothers, researchers were able to accurately peg their due dates roughly half the time by sequencing nine types of circulating RNA in the blood. The test was about as reliable as using ultrasound, currently the go-to method of establishing a due date.

To see if they could pick out preterm from full-term pregnancies, the researchers scanned all the free-floating RNAs in women’s blood and found 38 had levels that were distinctive for each group. Using combinations of particular  transcripts, they were able to pick out six of eight pregnancies that ended early and misclassified one out of 26 that went full-term, among a subset of women who were known to be at high risk for prematurity.

In the case of the preterm prediction, it’s mostly maternal genes  producing the relevant RNA, rather than the placenta-based transcripts from the due-date predictor