Nov 23, 2025 22:00:00

New clues found to understand the causes of habitual miscarriage

A research group from

the University of Sydney 's Victor Chan Heart Institute and Royal Women's Hospital has announced the results of a study that could shed light on the mechanism behind habitual miscarriage, a serious problem that affects a significant proportion of couples trying to conceive, with one in 50 cases occurring.

Identification of potential NAD-related biomarkers of recurrent miscarriage risk
https://academic.oup.com/humrep/advance-article/doi/10.1093/humrep/deaf195/8307317

New clues to why some women experience recurrent miscarriage
https://medicalxpress.com/news/2025-11-clues-women-recurrent-miscarriage.html

An Australian research team led by Dr. Hartmut Knie and Professor Sally Dunwoody investigated whether individual differences in the metabolism of vitamin B3 (niacin) and NAD (nicotinamide adenine dinucleotide) in the body are involved in the cause of miscarriage. Professor Dunwoody's 2017 study showed that 'in a mouse model, low NAD levels cause congenital abnormalities and miscarriage, but this can be prevented by vitamin B3 supplementation,' suggesting that NAD deficiency may be a contributing factor to miscarriage.

Analysis of blood, plasma, and urine samples from 88 women who had experienced two or more consecutive miscarriages and women with no history of miscarriage revealed clear changes in three NAD-related metabolites in women who had experienced recurrent miscarriages. These differences were observed regardless of whether or not they took vitamin B3 supplements, suggesting that metabolic imbalances may be involved. It has been revealed that in humans, not only is NAD insufficiency present, but changes in the metabolic process of vitamin B3 also play an important role.

Building on these findings, the research team is embarking on a new three-year project due to begin in February 2026. Three groups of women will be recruited from the Royal Hospital for Women and Nepean Hospital: those with a history of recurrent miscarriage, those currently experiencing recurrent miscarriage, and those with no history of miscarriage. Blood and urine samples will be collected from these groups, who will complete detailed health and lifestyle questionnaires, as well as assess NAD levels and related metabolites to determine:

- Identifying NAD-related biomarkers that may indicate an increased risk of miscarriage
- Investigating how the timing and number of miscarriages correlate with NAD metabolite levels
-Evaluation of the effects of dietary content and nutritional supplements on NAD metabolism
- Examining other clinical factors that may interact with NAD metabolism and the risk of recurrent miscarriage

It is hoped that this research will ultimately lead to the development of diagnostic tests to identify women at risk of recurrent miscarriage, and that a better understanding of the biological mechanisms involved may one day make it possible to prevent some miscarriages. 'Our goal is to understand the biological mechanisms behind this so that fewer families have to go through this grief,' says Dr. Cuny.