Blood Markers May Help Predict Delivery Time

(Reuters Health) – Scientists have identified markers in blood that may indicate labor is approaching, according to a new study.

Through an analysis of blood samples gathered during the second and third trimesters of 53 women, researchers identified a combination of factors that predicted the approach of labor to within a two week window, according to the report published in Science Translational Medicine.

“Currently it is hard for an obstetrician to give an accurate time when a woman is going to go into labor,” said coauthor Dr. Brice Gaudilliere of Stanford University. “This can be an issue both for pregnancies that turn out to be preterm and those complicated by being post term.”

“By measuring various factors that represent many physiological systems that are important in the maintenance of pregnancy–in particular the immune system –we are able to predict when labor will occur without relying on an estimate of the gestational age,” Gaudilliere said.

Dr. Gaudilliere and his colleagues analyzed blood samples from 53 women who went into labor spontaneously, including five who delivered preterm.

Blood was collected two or three times from the women during the last 100 days of their pregnancies, with each sample analyzed for 7,142 metabolic, protein and single-cell immune features. The data was plotted against the number of days before labor that each sample was collected, and via mathematical modeling, the researchers identified which features in the blood best predicted the onset of labor.

Once they had isolated the factors that appeared to presage the onset of labor within a window of two weeks, Dr. Gaudilliere and his team tested their results on the pregnancies of 10 more women, which confirmed the researchers were on the right track.

Overall, the researchers found that a surge in steroid hormone metabolites and interleukin-1 receptor type 4 preceded labor, coinciding with a switch from immune activation to regulation of inflammatory responses.

Dr. Gaudilliere and his team hope that the study’s findings will yield a test that obstetricians can use to predict labor within the next two to three years.

The new research is “interesting and intriguing,” said Dr. Hyagriv Simhan, executive vice chair for obstetrics in the department of ob-gyn at the Magee Womens Hospital of UPMC. “The approach is what is appealing. But it is a ways from being ready for prime time.”

Beyond that, Dr. Simhan wasn’t convinced the method would work to predict preterm deliveries. “Preterm deliveries are distinct in a variety of ways,” he said. “And the markers might be different. Preterm labor is not just normal physiologic labor starting earlier. It sometimes is fundamentally pathologic. So it’s not as likely that we will be able to predict it.”

If a test is eventually developed, it might help obstetricians counsel women who are going late, especially those who are not comfortable with being induced, Dr. Simhan said.

SOURCE: Science Translational Medicine, online May 5, 2021.

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