The Genetics of Preterm Birth: True Labor or False Labor?

Most women with threatened preterm labor between 20 and 37 weeks’ gestation will go on to complete their pregnancies. However, a small percentage of women will have a spontaneous preterm birth. Scientists looking to better predict who is most at risk for having a spontaneous preterm birth have turned to studying genes in the hopes that a blood test may provide an answer.

Seeking to develop a blood test, researchers collected peripheral blood from 154 women with threatened preterm labor and evaluated the differences between those who ultimately did have spontaneous preterm birth and those who didn’t. Of the participants, 48 went on to have a spontaneous preterm birth within 48 hours of hospitalization for threatened preterm labor. 

Pertinent Points

- A blood-based diagnostic test accurately predicted whether 70% of pregnant women with threatened preterm labor would or would not go on to have a spontaneous preterm birth.

- The researchers discovered a set of nine genes, coupled with clinical blood data, that could help identify which patients would or would not give birth within 48 hours of hospital admission for threatened preterm labor.

In analyzing the differentially expressed genes from the blood samples, the researchers discovered that a set of nine genes, coupled with clinical blood data, could classify whether 70% of participants would or would not have a spontaneous preterm birth within 48 hours of hospital admission.

"We want to develop a test that can differentiate between true and false labor so that women in true labor can receive the appropriate medical care, while women in false labor will receive supportive care and be discharged," said of the researchers, Stephen Lye, PhD, of the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada, in a news release.

A test would eliminate unnecessary hospitalizations among women who are in false labor, he explained.

Lye and his colleague Jan Heng, PhD, unveiled the results last week in the journal PLOS ONE.

Among the other findings, Heng and Lye noted that total leukocyte and neutrophil counts were significantly higher (35% and 41% higher, respectively) in the 48 women who actually delivered compared with the women who did not deliver within 48 hours (P<0.001).

Still, the researchers reported that there was no difference in the urine, vaginal, and placental microbiology and histopathology reports between the two groups of women.

In addition, the predictive efficacy of the nine gene signature coupled with clinical blood data outperformed the fetal fibronectin test, which 62 women received.

Together, these findings highlight the advantages of a blood-based diagnostic test for spontaneous preterm birth, the researchers stated. As a diagnostic test, it could be performed on all women and as part of routine blood work, the researchers suggested. And in terms of future research, this study may lead the way for a blood-based systems biology approach to better understanding and identifying those at risk for spontaneous preterm birth.