Researchers found that women who have experienced multiple miscarriages have different levels of certain molecules in their blood and urine compared to women who haven’t. These molecules are related to how the body uses a nutrient called NAD (nicotinamide adenine dinucleotide), which is important for healthy pregnancy. The study of 88 women suggests these blood markers could potentially help doctors identify women at higher risk for miscarriage before they become pregnant again. While the findings are promising, the research is still in early stages and needs to be tested in larger groups of women.

The Quick Take

  • What they studied: Whether women who have had multiple miscarriages have different levels of NAD-related molecules in their blood, plasma, and urine compared to women without miscarriage history
  • Who participated: 88 women aged 20-40 years old: 37 who had experienced two or more miscarriages in a row, and 51 who had not experienced miscarriages. All participants were not currently pregnant when tested.
  • Key finding: Women with recurrent miscarriage had higher levels of three specific molecules (1MNA, 2PY, and 4PY) in their blood and urine. When these three molecules were measured together with the woman’s age, they correctly identified miscarriage risk about 89% of the time.
  • What it means for you: This research suggests doctors may eventually be able to use simple blood or urine tests to identify women at higher risk for miscarriage before pregnancy. However, this is early-stage research, and these tests are not yet available for clinical use. Women with recurrent miscarriage should continue working with their healthcare providers on proven prevention strategies.

The Research Details

This was a pilot cohort study, which means researchers followed a group of women and compared two subgroups: those with and without miscarriage history. The study took place at a hospital in Sydney, Australia, between March 2022 and December 2023. All participants were between 20 and 40 years old and not currently pregnant when they joined the study.

Women completed detailed questionnaires about their health, lifestyle, diet, and medications. They then provided blood and urine samples collected in the morning after fasting (not eating). Researchers measured 26 different NAD-related molecules in these samples using advanced laboratory equipment that can detect very small amounts of substances.

The researchers used statistical methods to compare the two groups and identify which molecules were different between women with and without miscarriage history. They also used computer learning programs to test whether these molecules could predict miscarriage risk.

This research approach is important because it looks for biological markers—measurable signs in the body—that might explain why some women experience recurrent miscarriage. By measuring multiple related molecules rather than just one, the study provides a more complete picture of how NAD metabolism differs in women with miscarriage history. The use of machine learning helps determine which combinations of markers are most useful for prediction.

Strengths: The study used validated laboratory methods to measure molecules accurately, and all participants were carefully selected and characterized. The research was conducted at a single hospital, which ensures consistent procedures. Limitations: The sample size is small (88 women), which means findings may not apply to all women. The study only measured molecules once, so it doesn’t show whether levels change over time. The research was conducted in Australia, so results may differ in other populations. Most importantly, this is a pilot study, meaning it’s designed to test whether the idea is worth pursuing in larger studies, not to provide definitive answers.

What the Results Show

Women with recurrent miscarriage had significantly higher levels of three molecules called 1MNA, 2PY, and 4PY in their blood and urine. These molecules are byproducts of how the body processes NAD. The difference was consistent across all three types of samples tested (whole blood, plasma, and urine), suggesting these are reliable markers.

When researchers looked at 1MNA in plasma specifically, they found that for every small increase in this molecule, the odds of having experienced miscarriage increased by about 2%. This relationship remained even after accounting for the woman’s age.

When researchers combined information about all three molecules (1MNA, 2PY, and 4PY) along with the woman’s age, they could correctly identify whether a woman had experienced recurrent miscarriage about 89% of the time. This is much better than using age alone.

Two additional molecules—anthranilic acid in blood and nicotinamide (NAM) in urine—were also elevated in women with recurrent miscarriage, though these were not as strong as the other three markers.

The study found that the three main molecules (1MNA, 2PY, and 4PY) showed strong positive correlations with each other across all three sample types. This means if one was high, the others tended to be high too, which strengthens confidence in these as reliable markers. The research also noted that several health conditions already known to increase miscarriage risk—such as inflammation, obesity, and advanced maternal age—are also associated with changes in NAD metabolism, suggesting these molecules may reflect underlying biological problems.

This is one of the first studies to systematically examine NAD-related molecules in women with recurrent miscarriage. Previous research in animal models (mice) showed that raising NAD levels during pregnancy could prevent miscarriage and birth defects. This human study provides the first evidence that NAD metabolism is actually different in women experiencing recurrent miscarriage, supporting the idea that NAD may play a role in pregnancy loss.

The study included only 88 women from one hospital in Australia, so results may not apply to all women worldwide. The researchers measured molecules only once, providing a snapshot rather than showing how levels change over time or during pregnancy. The study couldn’t determine whether these molecules cause miscarriage or are simply markers of other underlying problems. The women were tested when not pregnant, so the results may not reflect what happens during pregnancy when miscarriage actually occurs. Finally, this is a pilot study designed to test whether the idea is worth pursuing further, not to provide definitive clinical answers.

The Bottom Line

Current evidence level: Early-stage research (pilot study). At this time, there are no clinical recommendations based on this research. Women with recurrent miscarriage should continue working with their healthcare providers on proven approaches, which may include testing for blood clotting disorders, infections, immune problems, and structural issues with the uterus. Future research may lead to new blood tests to identify at-risk women, but this is not yet available.

Women with recurrent miscarriage and their healthcare providers should be aware of this emerging research. Researchers studying miscarriage prevention should pay attention to NAD metabolism as a potential target. Women without miscarriage history do not need to take action based on this research. This research does not apply to women with single miscarriages, as the study focused on recurrent miscarriage (two or more in a row).

This is very early-stage research. It will likely take several years before these findings are confirmed in larger studies and potentially developed into a clinical test. Even if a test becomes available, it would be used to identify risk, not to treat the problem. Treatment approaches would need to be developed separately.

Want to Apply This Research?

  • Track dietary intake of B vitamins (especially B3/niacin) and overall nutrition quality, as NAD is related to B vitamin metabolism. Users could log daily B vitamin sources and note any symptoms or health changes. This creates a baseline for future discussions with healthcare providers.
  • Users with recurrent miscarriage history could use the app to monitor and optimize their diet, particularly ensuring adequate B vitamin intake from sources like chicken, tuna, turkey, peanuts, and mushrooms. They could also track lifestyle factors known to affect miscarriage risk, such as stress levels, sleep quality, exercise, and weight management.
  • Create a long-term health tracking dashboard that monitors overall wellness factors associated with miscarriage risk: nutrition quality, exercise, stress management, sleep, weight trends, and medical appointments. This helps users maintain healthy habits while waiting for future research to develop into clinical tools. Users should share this information with their healthcare providers.

This research is preliminary and has not yet been validated for clinical use. The findings are from a small pilot study and should not be used to make medical decisions. Women with recurrent miscarriage should work with their healthcare providers to identify causes and develop personalized prevention strategies using proven approaches. This article is for educational purposes only and does not replace professional medical advice. Anyone concerned about miscarriage risk should consult with their obstetrician or reproductive health specialist.