Can Sperm Cause Miscarriage? What a Normal Semen Analysis Might Miss
Can Sperm Cause Miscarriage? What a Normal Semen Analysis Might Miss
Can sperm cause miscarriage, even when your partner's semen analysis has come back completely normal?
Yes, sperm can be part of the miscarriage picture. And it's something that can get overlooked when all the attention is on the female.
Think about it.
You've experienced a miscarriage, perhaps more than once. You've had blood tests, hormone checks, scans and all sorts of investigations.
And everything seems to be coming back normal.
Meanwhile, your partner had a semen analysis, was told his sperm count and movement were fine, and that was that.
But here's something you might not realise.
A normal semen analysis doesn't necessarily mean the DNA inside those sperm is undamaged. It's explaining things like how fast they swim, their shape, not what their constitution is.
Researchers are learning more about why that distinction may matter when couples experience repeated miscarriages.
Can sperm really contribute to miscarriage?
Absolutely. After all, your partner provides half the embryo's nuclear genetic material.
We tend to focus heavily on the egg because maternal age is such an important factor in embryo chromosome abnormalities.
But sperm carries genetic instructions too.
And those instructions need to be intact enough to support normal embryo development.
So while an egg can fertilise successfully and a pregnancy can begin, that doesn't automatically tell us everything about the genetic material the sperm contributed.
That's why some researchers have been investigating sperm DNA damage in couples experiencing recurrent miscarriage.
And the findings are interesting.
What is sperm DNA fragmentation?
Think of sperm DNA like an instruction manual.
When the sperm fertilises an egg, it delivers genetic information needed for the embryo to develop.
Now imagine some of the pages in that manual have been torn or damaged.
The instructions are still there, but parts may be harder to read correctly.
That's a simple way of understanding sperm DNA fragmentation — breaks in the genetic material carried by sperm.
Some DNA damage can be repaired by the egg after fertilisation. But that repair capacity isn't unlimited.
And studies have found that men whose partners experience recurrent miscarriage tend, on average, to have higher levels of sperm DNA fragmentation than men in comparison groups.
In fact, the American Society for Reproductive Medicine's 2026 guidance recognises this association and recommends considering testing in selected couples with unexplained recurrent miscarriage.
Now, that doesn't mean sperm DNA fragmentation caused every miscarriage in those studies.
But it does give us another useful piece of the fertility puzzle. And ladies, I know how frustrating this can be when your guy insists there's 'Nothing wrong with me'. But we have answers.
If you've experienced repeated losses with no clear explanation, wouldn't you want to know whether his side of the equation has been properly considered?
Can sperm DNA fragmentation be high when his semen analysis is normal?
Yes. And this is probably the most important thing to understand.
A standard semen analysis usually looks at things such as sperm count, movement and shape.
Think of it like inspecting cars coming off a production line.
You count how many cars there are, check that they're moving and look to see whether they appear properly assembled.
But that doesn't tell you whether all the wiring inside is in good condition.
Sperm DNA fragmentation testing looks at something different: damage to the genetic material inside the sperm.
So a man can have reassuring semen parameters and still have elevated DNA fragmentation.
That doesn't mean every man with normal results needs additional testing.
It means that when there's a history of repeated unexplained miscarriages, the normal semen analysis might not be the end of the conversation.
What causes sperm DNA fragmentation?
This is where things get particularly interesting, because sperm DNA damage can be associated with several different factors.
Researchers have identified generic contributors. The main ones are as below but there's a tonne of others too:
Smoking and environmental exposures: Certain chemicals and tobacco smoke can increase oxidative stress and damage sperm DNA.
Varicocele: Enlarged veins around the testicle can affect sperm production and may be associated with higher DNA fragmentation.
Illness and fever: A significant fever can temporarily affect sperm development.
Age: Increasing paternal age is associated with changes in sperm DNA integrity.
Metabolic and general health: Excess weight and some health conditions may be associated with poorer sperm health.
And here's why this so important.
Not all these factors are fixed.
Some are modifiable, while others warrant medical assessment.
But that doesn't mean we should automatically put every man on supplements or assume he has a problem.
The first question is whether there's actually a reason to investigate.
And the second is what the findings mean for that particular couple.
Can improving sperm health reduce the risk of miscarriage?
There's something encouraging about sperm production. Unlike a woman's eggs, sperm are continually being produced. It takes roughly two to three months for new sperm to develop and mature. So changes in a man's health or exposures may influence sperm produced over the following months.
For example, stopping smoking, addressing significant lifestyle risks and seeking treatment for a relevant medical condition can be worthwhile.
But there's an important distinction.
Improving a sperm DNA fragmentation result hasn't yet been conclusively shown to prevent recurrent miscarriage.
And I wouldn't want you spending money on an enormous collection of antioxidants simply because somebody says they're good for sperm. Because the same applies to men as applies to ladies, if your body isn't able to take onboard those eg antioxidants, because of underlying issues, then the money, time and emotional investment is already wasted before you start.
Think about it.
If a man's sperm health is being affected by smoking, a varicocele or another specific issue, shouldn't we first understand that rather than throwing ten different supplements at him and hoping something works?
That's how I approach Fertility Bandwidth™.
Find out what actually deserves attention in HIS body because we're all different. Address the priorities. And avoid overwhelming either partner with changes that may not be relevant.
Should my partner have sperm DNA fragmentation testing after miscarriage?
This depends on your history.
After one miscarriage, particularly where there was a confirmed sporadic chromosome abnormality, specialist sperm DNA testing isn't routinely necessary.
But if you've experienced two or more miscarriages, especially where the cause remains unexplained, discussing male-factor evaluation becomes more relevant.
ASRM's 2026 guidance says sperm DNA fragmentation testing may be considered in couples with otherwise unexplained recurrent pregnancy loss or recurrent pregnancy loss alongside infertility.
A reproductive urologist or fertility specialist can help determine whether testing is appropriate, how to interpret the result and whether anything clinically relevant needs attention.
And remember, sperm DNA fragmentation isn't the same as sperm chromosome abnormalities.
If miscarriage testing identifies an inherited structural chromosome rearrangement, genetic counselling and parental chromosome testing may be more relevant.
The right test depends on the question we're trying to answer.
Why looking at both partners matters
Let's imagine you've been through several miscarriages.
Your blood tests are reassuring.
Your scans haven't revealed anything significant.
And your partner's semen analysis has been described as normal.
It's easy to reach the conclusion that there's nothing else to investigate.
But have you both had your reproductive histories considered together?
Has anyone asked about his health, medications, smoking, illnesses or other relevant exposures?
Does your miscarriage history justify looking more closely at sperm DNA?
And have your previous pregnancy chromosome results been properly interpreted?
Because fertility isn't simply about whether the woman can get pregnant.
It's about two people contributing to the development of an embryo, followed by the complex process of establishing and supporting a pregnancy.
That's why Fertility Bandwidth looks at the wider picture rather than treating every fertility result as an isolated piece of information.
Sometimes the most useful next step is a medical investigation.
Sometimes it's addressing an identified health issue.
And sometimes it's recognising that the results you already have are genuinely reassuring.
The aim isn't to find more things wrong with either of you.
It's to understand where your attention is actually needed.
If you're still wondering why miscarriages keep happening despite reassuring results, read my companion article: Why Do I Keep Miscarrying When Tests Are Normal?
What should we do before trying again?
I'd start with three questions.
1. Have we properly understood the previous miscarriage results?
If genetic testing was performed, what did it actually show? Was there a chromosome abnormality, or is the cause still unexplained?
2. Has my partner's reproductive health been considered?
Not simply whether his sperm count was normal, but whether anything in your combined history suggests further male-factor assessment would be useful.
3. Do we know what genuinely deserves attention before another pregnancy?
Because there's an enormous difference between making ten changes in the hope that one might help and understanding why a particular change is relevant to your situation.
And that's where I would love you to start thinking differently.
At Fertility Bandwidth, we look at your fertility history as a couple, helping you understand the information you already have and recognise which areas may deserve further investigation or support.
Rather than both of you following another enormous fertility checklist, we start by understanding what's actually relevant.
If you'd like a clearer idea of where to begin, take my Free Fertility Analysis.
START MY FREE FERTILITY ANALYSIS
Because when you're trying to build a family together, surely it makes sense to consider both sides of the equation?
Frequently asked questions
Can poor sperm quality cause miscarriage?
Certain sperm factors, including elevated DNA fragmentation and some genetic abnormalities, are associated with miscarriage. But an abnormal sperm result alone doesn't establish the cause of an individual pregnancy loss.
Can sperm DNA fragmentation cause a chromosomal miscarriage?
Sperm DNA fragmentation and embryo chromosome-number abnormalities are different problems. Sperm can contribute genetic abnormalities to embryos, but elevated fragmentation doesn't necessarily mean sperm caused an aneuploid miscarriage.
Can sperm DNA fragmentation improve?
Sometimes. Certain lifestyle changes or treatment of an underlying medical problem may reduce fragmentation, although evidence that doing so prevents recurrent miscarriage remains limited.
About Karen Botha
Karen Botha is the founder of Fertility Bandwidth™, helping women and couples understand their wider reproductive health, make sense of fertility results and identify what genuinely deserves attention before pregnancy or IVF.
Her approach focuses on individualised preparation, recognising relevant patterns and helping couples make better-informed decisions alongside their medical care.
Research and references
This article is educational and doesn't replace individual medical assessment, genetic counselling or fertility treatment.
Evidence reviewed: November 2026.
