Blood test predicts if false labor is headed for delivery room

A blood test may be able to discern false labor from the real thing, an international team of researchers reports May 14 in PLOS ONE. False labor is marked by preterm contractions that stop short of true labor, allowing the pregnancy to continue. But about 5 percent of women with early contractions do go into labor and deliver within 10 days, the authors note.

It can be hard to predict which women are truly in labor because half of women who have preterm contractions can’t undergo the standard prediction test for false labor, and the test itself isn’t foolproof.

As a new approach, researchers examined blood samples taken from 154 pregnant women at the start of preterm contractions that began 24 to 36 weeks into their pregnancy. Of this group, 48 went on to have a spontaneous preterm birth.

Analysis of the blood showed that women who went into true labor within 48 hours had substantially more white blood cells in circulation than women who turned out to be in false labor. The scientists also combed through genetic data and found nine genes that were considerably under- or over-activated in the women who then had a preterm birth. Using the white blood cell information and the nine genes as markers of imminent birth, the researchers calculated they could correctly predict about 71 percent of the time which women in the throes of premature contractions would be headed for a preterm birth.