Atlanta: A new study has found that blood samples collected during pregnancy may reveal early molecular signs that indicate whether a woman is at risk of delivering her baby prematurely.
Researchers from Emory University discovered distinct biological patterns in the blood of pregnant women whose pregnancies ended in preterm or early-term births, with some differences detectable as early as the first trimester.
The findings, published in the journal Nature Health, could pave the way for earlier identification of high-risk pregnancies and improve efforts to prevent complications associated with premature birth.
Why Preterm Birth Matters
Preterm birth occurs when a baby is born before completing 37 weeks of pregnancy. Early-term births refer to deliveries that take place during weeks 37 or 38, slightly earlier than the ideal full-term period.
Although babies born during these stages often survive, they may face increased health risks because critical organs such as the brain, lungs and nervous system continue developing during the final weeks of pregnancy.
Premature birth has been linked to breathing difficulties, hearing problems, developmental delays and a range of long-term health complications.
Because of these risks, scientists have been working to identify biological warning signs that could help predict which pregnancies may end early.
Study Examined More Than 500 Pregnant Women
The research team conducted a metabolome-wide association study involving more than 500 pregnant women participating in the Atlanta African American Maternal-Child Cohort, a long-term study conducted between 2014 and 2018.
Blood serum samples were collected during two key stages of pregnancy:
- Early pregnancy (8–14 weeks)
- Later pregnancy (24–30 weeks)
Researchers then analysed the participants’ metabolomes — the complete set of small molecules and metabolites circulating in the body — to identify biological patterns linked to birth outcomes.
A metabolome-wide association study allows scientists to examine how thousands of metabolites are connected to specific health conditions or events.
Distinct Molecular Signatures Identified
The study revealed that pregnancies ending in spontaneous preterm births showed a very different biological profile compared to pregnancies in which early delivery occurred because of medical complications.
Researchers found that women who experienced spontaneous early labour frequently showed alterations in amino acid-related metabolic pathways.
Amino acids are essential building blocks of proteins and play a crucial role in supporting fetal growth, placental function and the body’s ability to respond to physiological stress.
In contrast, women who underwent medically indicated early deliveries displayed metabolic changes associated with fat metabolism, cardiovascular stress and energy utilisation.
The researchers concluded that the two types of preterm birth appear to arise through different biological mechanisms.
“Distinct metabolic profiles differentiated spontaneous and medically indicated preterm birth and early term birth across pregnancy windows,” the study authors wrote.
Amino Acid Changes Linked To Spontaneous Early Birth
Several amino acid pathways were found to be disrupted among women who experienced spontaneous preterm birth.
These included pathways involving:
- Arginine
- Proline
- Aspartate
- Glutamate
- Methionine
- Cysteine
According to researchers, these pathways are closely linked to inflammation, oxidative stress and immune responses during pregnancy.
Oxidative stress occurs when harmful molecules known as free radicals overwhelm the body’s antioxidant defences, potentially affecting placental health and fetal development.
The study also highlighted alterations in amino acids such as:
- Valine
- Leucine
- Tyrosine
These changes were strongly associated with spontaneous preterm deliveries.
Different Markers Found In Medically Indicated Births
Pregnancies that ended early due to medical complications showed a different set of metabolic signals.
Researchers identified significant changes involving:
- Acylcarnitine, a molecule involved in fat metabolism and energy production
- Aldosterone, a hormone that helps regulate blood pressure and fluid balance
These biomarkers may reflect stress on the mother’s cardiovascular and metabolic systems, potentially contributing to medically necessary early deliveries.
The findings suggest that monitoring these molecules could help doctors better understand the biological processes leading to different types of preterm birth.
Potential For Earlier Risk Detection
One of the most significant aspects of the study is that some molecular differences were detected during the first trimester, months before delivery.
This raises the possibility that simple blood-based screening tests could eventually help identify women at higher risk of premature birth much earlier than current methods allow.
Early identification could enable healthcare providers to offer closer monitoring, targeted interventions and personalised treatment strategies aimed at prolonging pregnancy and improving outcomes for both mother and baby.
More Research Needed
While the findings are promising, researchers emphasised that further studies involving larger and more diverse populations are needed before the results can be translated into routine clinical practice.
Future research will focus on validating these biomarkers and determining whether they can be used to develop reliable predictive tests for preterm birth.
If confirmed, such tests could represent a major breakthrough in maternal and fetal healthcare by helping doctors identify vulnerable pregnancies long before complications arise.
A Step Towards Better Maternal Care
The study adds to growing evidence that subtle molecular changes during pregnancy can provide valuable clues about future health outcomes.
By uncovering biological signatures linked to preterm and early-term births, researchers hope to improve understanding of pregnancy complications and ultimately reduce the global burden of premature births.
The findings could also help advance precision medicine approaches in obstetrics, where care is tailored to an individual’s unique biological profile rather than relying solely on traditional risk factors.