What Sperm DNA Can Tell Us About Miscarriage and Fertility Struggles
When "Everything Looks Normal" but You’re Still Not Pregnant
When people come to me for fertility support, they’ve often already been through a lot. Blood tests, semen analysis, maybe even IVF. But sometimes, despite being told repeatedly that everything looks "normal," pregnancy either doesn’t happen or ends before it should.
What Is Sperm DNA Fragmentation?
One possible reason is sperm DNA fragmentation. This refers to small breaks or damage in the DNA carried by sperm. It’s not something a standard NHS semen analysis will detect, but it can have a significant impact on fertilisation, embryo development and early pregnancy.
The Research: Sperm DNA and Miscarriage Risk
A 2023 review published in Andrology found that men with high levels of sperm DNA fragmentation were much more likely to be part of a couple experiencing recurrent pregnancy loss (PubMed). An earlier meta-analysis in Human Reproduction showed that miscarriage risk more than doubled in cases where sperm DNA was significantly damaged (PubMed).
What Causes Sperm DNA Damage?
There are several factors that can cause this kind of DNA damage, including oxidative stress from smoking, poor diet, environmental toxins, repeated heat exposure (such as from hot baths or laptops), and ageing. Conditions such as varicocele or chronic infection can also contribute.
Why Egg Health Still Matters Too
The egg may try to repair this damage after fertilisation, but its ability to do so depends on egg quality and mitochondrial health. Both naturally decline with age. Mitochondria also power sperm movement, so if they’re under strain, motility and fertilisation may be affected.
The Role of Vaginal pH and Timing
During ovulation, the vaginal environment becomes more alkaline to support sperm survival. But even under ideal conditions, severe DNA damage can interfere with healthy embryo development.
What You Can Do About It
If you’ve had IVF that didn’t work, experienced early miscarriage, or are facing unexplained infertility, testing for sperm DNA fragmentation can offer valuable insights. In many cases, changes in diet, supplements, lifestyle or sperm retrieval method can make a meaningful difference.
And if egg health is also part of the picture, looking at both partners gives us the best chance of success. We always get the best outcomes when men take responsibility for their side of the problem.
Support That’s Personalised and Evidence-Based
And while this can all feel very overwhelming, working with a fertility specialist can help you navigate it with support and clarity. A specialist can help you understand which tests are worth doing, interpret results in the context of your unique situation, and create a personalised plan that supports both partners. You don’t have to figure it all out on your own — and you’re not expected to.
Book a Free Chat
If you’re trying to conceive and want to explore whether sperm DNA fragmentation could be playing a role, I’m here to help you understand your options. Together, we can create a supportive, personalised plan to give you the best possible chance of a healthy pregnancy.
Book an appointment or get in touch if you’d like to talk it through..
