HMN 2026: How Molecular clues in maternal blood may predict preterm birth

New research has found signs that may help researchers better understand why some babies are born early. Some signs are present as early as the first trimester.

Preterm births (when a baby is born before week 37 of pregnancy) and early-term births (when a baby is born in week 37 or 38 of pregnancy) can have lasting health effects. Babies are still growing their brain, lungs and other organs during the final weeks of pregnancy. When a baby is born too early, they can have breathing problems, hearing loss, vision problems, and more.

In a study published in Nature Health, researchers from Emory University’s Rollins School of Public Health looked for molecular differences between pregnancies that ended early and those that reached full term. They studied this using blood samples from pregnant African American women in Atlanta.

The research team also investigated molecular differences between early births that happened spontaneously and those that happened because of medical concerns affecting the mother or baby.

Key findings:

• There are molecular signs in the mother’s blood that may help researchers understand whether a pregnancy is more likely to end in a preterm, early-term or full-term birth.
• Those signs are different for babies spontaneously born early and babies delivered early because of medical concerns.
• In pregnancies that ended in spontaneous early births, the mother’s blood often showed differences in amino acids. Amino acids are the building blocks of protein, and they also help support a baby’s growth, the placenta and the body’s response to stress.
• In pregnancies where the mother delivered early for medical reasons, the mother’s blood showed molecular signs related to how the body uses fat for energy and responds to stress on the heart and metabolism.

What this means for pregnant women

These findings provide biological clues that may help researchers and clinicians better understand early birth, and—in the future—develop improved tools to identify pregnancies at higher risk.

“Preterm and early-term births are not one single condition with one single cause,” says Donghai Liang, Ph.D., associate professor of environmental health at Rollins and the study’s lead author. “Our study shows that different types of early birth carry distinct molecular fingerprints during pregnancy. These findings may help us better understand the biology of early birth, and—eventually—develop better tools to identify risk earlier and guide prevention strategies.”

For pregnant women today, the most important steps remain early and regular prenatal care, managing conditions such as high blood pressure or diabetes, avoiding tobacco and substance exposures, and eating a balanced diet. Pregnant women should always discuss any concerns with a health care provider.

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