Blood tests make birth dates more predictable

Trials show they are an accurate way of maternal screening

Women could soon know how far along they are in pregnancy and their risk of premature delivery by having simple blood tests, according to US researchers.

Based on fetal RNA, they say the tests can predict how much time is left in a pregnancy with about the same accuracy and lower cost than current methods.

The study authors, from Stanford University in California, previously showed that the maternal blood contains free-floating RNA molecules, each one a transcript of genes that are active in both fetus and mother, and that the types and amounts of these molecules changed over the course of pregnancy.

In the current pilot study, they found that a combination of only nine RNAs could accurately predict the time remaining until delivery for both primigravida women and multigravida women.

The blood test's accuracy, within 14 days of the actual gestational age at delivery, was similar to that of ultrasound estimates.

An added benefit of the blood test is that, unlike the ultrasound, it doesn't rely on the woman's recollection of her last menstrual period.

The researchers also used a separate set of RNAs to identify women who were at risk of preterm delivery.

This test predicted preterm and full-term births with an accuracy exceeding 80%, the study found.

The researchers believe that similar blood tests can also be developed to identify and monitor fetuses with congenital defects that can be treated in utero. – Reuters

Read the full study here