Sperm DNA Fragmentation and Abnormal Embryos: What a New Study Shows
When the embryo results keep coming back abnormal
Few moments in IVF feel as heavy as opening genetic testing results and learning that most of your embryos are chromosomally abnormal. When it happens once, it is painful. When it happens again, couples understandably start asking what else could be going on, and whether anything has been missed.
Much of the conversation around embryo quality focuses on the egg. Egg quality, especially as it changes with age, remains the biggest factor in whether an embryo has the right number of chromosomes. But an embryo is made from two cells, and a large new study published in Human Reproduction Open in 2026 adds to a growing body of research suggesting that the health of the sperm's DNA may also play a part. For couples facing repeated abnormal results, this is a valuable aspect of embryo health worth understanding.
What is sperm DNA fragmentation?
A standard semen analysis looks at how many sperm there are, how well they swim, and what they look like. It does not tell us much about the genetic material each sperm carries. Sperm can look completely normal under the microscope and still carry DNA with breaks or damage in it.
Sperm DNA fragmentation testing measures how much of that damage is present. The result is usually reported as a percentage called the DNA fragmentation index, or DFI. In general, a lower number means more of the sperm carry intact DNA, while a higher number means more of them carry damaged DNA. Many clinics consider a DFI above roughly 30 percent to be high.
What the new study found
Researchers at a large fertility centre in China, led by Lou and colleagues, looked back at eight years of data from nearly four thousand couples going through IVF. More than three and a half thousand embryos had genetic testing to check whether they carried the correct number of chromosomes. The team then compared these results against the male partner's sperm DNA fragmentation level.
When the partner had high sperm DNA fragmentation, embryos were more likely to be aneuploid, meaning they had too many or too few chromosomes. Roughly 38 percent of embryos were aneuploid in the high fragmentation group, compared with about 24 percent in the low group. Even after the researchers accounted for factors like the age of both partners, smoking, and overall semen quality, the higher risk remained.
Interestingly, moderate levels of fragmentation did not appear to make a difference. The increased risk showed up mainly once fragmentation was high.
Which couples this may impact the most
The link was strongest in two groups. The first was couples where the female partner was 35 or older. In this group, about half of embryos were aneuploid when sperm DNA fragmentation was high, compared with closer to four in ten when it was low.
The researchers offer a thoughtful hypothesis for this. After fertilization, the egg carries out a marvellous function in which it can repair any damage in the sperm's DNA. However, as eggs age that repair capacity naturally declines. So when an older egg meets sperm carrying a heavier load of damage, the egg may simply be less able to keep up.
The second group was men with significantly reduced sperm count, movement, and shape. In these men, high fragmentation roughly doubled the rate of aneuploid embryos compared with low fragmentation.
The study also found that high fragmentation was linked to fewer top quality blastocysts in men under 40, suggesting the effects of damaged sperm DNA may show up more in later embryo development than in the first few days after fertilization.
A note on the limits of this research
This was a large study, but it reviewed at existing records from a single clinic, so it can show a link rather than prove that damaged sperm DNA directly causes abnormal embryos. Larger, forward looking trials are still needed before firm conclusions can be drawn.
Why it is worth a closer look
Even with these limits in mind, sperm DNA fragmentation is a reasonable thing to check for couples who have seen repeated aneuploid embryos, particularly when everything else that can reasonably be done is already being done. It is a simple test, and it looks at something a standard semen analysis cannot see.
This study also fits into a wider picture. Earlier reviews have linked high sperm DNA fragmentation with lower pregnancy rates in IVF and a higher risk of miscarriage and recurrent pregnancy loss. The research is not entirely consistent, but taken together, it suggests sperm DNA health deserves a place in the conversation rather than being overlooked.
The authors themselves note that approaches such as guided lifestyle changes, therapeutic antioxidant support, and advanced sperm selection techniques in the lab are worth studying for men with high fragmentation. Whether these improve embryo results has not yet been proven, which is exactly why a personalized conversation with a clinician who knows your history matters more than any general rule.
Next steps if you have had aneuploid embryos
Repeated abnormal embryo results can leave couples feeling as though they have run out of questions to ask. Sperm DNA fragmentation will not explain every case, and egg quality remains the biggest piece of the puzzle. Still, it is one more question worth asking, and one that brings the male partner's health fully into the picture.
If you have been through cycles with repeated aneuploid embryos and want to understand whether sperm DNA health could be part of your story, working with a fertility focused clinician can help you look at the full picture together, alongside your fertility clinic and the care you are already receiving.
Disclaimer
This article is for educational purposes only and is not medical advice. It is not intended to diagnose, treat, or prevent any condition. Individual circumstances vary, and decisions about your care should be made with your own healthcare team. If you are trying to conceive or are currently in treatment, please speak with your physician or a licensed naturopathic doctor before making changes.
Reference: Lou L, Xu P, Xie P, et al. High sperm DNA fragmentation is associated with increased embryonic chromosomal abnormality: a retrospective study of 8 years involving 5637 couples undergoing ART. Human Reproduction Open, 2026.
About Dr. Harsimranjeet Singh Bhatia, ND
Dr. H. Singh is an award winning Fertility Naturopath based in Ottawa with over ten years of experience focusing exclusively on reproductive health. He has been named Naturopath of the Year by Faces Magazine Ottawa four years in a row and received the 2026 Emerging Leader award from the Ontario Association of Naturopathic Doctors for his patient advocacy and impact within the community.
He works with individuals and couples across Ontario and Quebec, supporting patients trying to conceive naturally or alongside treatments such as IUI and IVF.
Care focuses on evidence informed strategies to support egg quality, sperm health, hormonal balance, implantation, and early pregnancy. Each plan is built around your own history and test results, and is designed to work alongside the care you receive from your fertility clinic.
If you would like dive deeper to understand where naturopathic care could fit into your fertility journey, you are invited to book an initial consultation.
