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When a pregnancy ends in miscarriage, the conversation almost always turns to the woman focusing on her age, hormones, uterus condition, and immune system. She gets tested, monitored, and counselled. The man is handed a cup and told his job is done once the semen results come back "normal." That has been the standard approach for decades. The sperm contributes half the genetic material that builds an embryo. If that contribution carries damaged DNA, disrupted genetic instructions, or immune interference, the embryo may not develop properly due to poor sperm health, regardless of how healthy the mother is.
Yet in most clinical protocols for recurrent pregnancy loss, the male partner receives little more than a basic semen analysis - a test that checks count, movement, and shape, but says nothing about the integrity of the DNA inside each sperm cell.
This article first answers the question whether poor sperm health causes miscarriage. Additionally, it covers how sperm DNA fragmentation, DNA methylation abnormalities, and antisperm antibodies can contribute to miscarriage - and why a standard semen analysis alone is not enough to detect them.
Miscarriage Is More Common Than Most People Realise
Globally, miscarriage affects around 15% of all recognised pregnancies. A major 2021 analysis put the worldwide figure at approximately 23 million pregnancy losses every year - roughly 44 every single minute. The true number is likely higher still, because many early losses go unrecorded. (1)
Despite how common this is, the cause often goes unexplained. In up to 50% of recurrent pregnancy loss (RPL) cases, no clear reason is identified even after full investigation. The European Society of Human Reproduction and Embryology (ESHRE) defines RPL as the loss of two or more pregnancies, and its 2022 updated guidelines acknowledge that unexplained loss remains one of the most frustrating challenges in reproductive medicine (2).
So when half of all cases remain without an answer, it raises a fair question: are we testing the right person?
The Male Side of the Equation
A sperm cell does not just deliver DNA and disappear. Its genetic and epigenetic material actively shapes how the embryo develops during its earliest and most fragile days. If that material is damaged due to poor sperm health, development can stall or fail entirely, long before a heartbeat is ever detected.
A 2025 review found that men whose partners experienced recurrent miscarriage consistently showed higher levels of sperm DNA damage causing poor sperm health compared to men with fertile partners. A 2022 meta-analysis involving male partners of women with RPL found that these men had significantly higher DNA Fragmentation Index (DFI) scores, compared to men whose partners had successful pregnancies. Those findings were confirmed again in a 2022 updated meta-analysis. (3)
What Is Sperm DNA Fragmentation?
Standard semen analysis checks sperm count, movement, and shape. What it cannot detect is whether the DNA inside each sperm cell is actually intact. Sperm DNA fragmentation (SDF) refers to breaks or damage within that genetic material, and it can be present even when every standard result looks completely normal.
A 2025 study revealed that 61% had raised global DNA fragmentation and 52% had raised double-stranded DNA fragmentation. The researchers concluded that male investigation is essential in couples experiencing RPL, precisely because standard testing misses these abnormalities (4).
A separate study in Scientific Reports in 2024 found a direct positive correlation between DFI and miscarriage rate in assisted reproduction, with risk rising significantly when DFI exceeded 30%. (5)
What causes elevated fragmentation? Smoking, obesity, varicoceles, chronic infections, environmental toxin exposure, and advanced paternal age have all been linked to higher SDF levels. Oxidative stress is a key mechanism. When the body cannot neutralise free radicals fast enough, sperm DNA becomes vulnerable to damage causing poor sperm health that the embryo has to try to repair after fertilisation.
The Role of Sperm DNA Methylation
Beyond fragmentation, there is another layer of sperm health that has only recently started receiving proper attention: DNA methylation. This is an epigenetic process. It does not change the DNA sequence itself, but it controls which genes are switched on or off during early embryo development.
Sperm carry epigenetic instructions the embryo uses in its earliest cell divisions. If those instructions are disrupted, gene expression during embryogenesis goes wrong and the pregnancy can fail even when chromosomes appear normal.
A 2025 study found specific methylation abnormalities in the sperm of male partners from couples with unexplained RPL, identifying disrupted sites, which is known to be critical for embryo growth. (6) A 2021 review in Frontiers in Immunology reached a similar conclusion, noting that abnormal sperm DNA methylation may directly or indirectly affect embryo implantation and development, contributing to RPL. (7)
Antisperm Antibodies
Antisperm antibodies (ASA) are immune proteins that can attach to the surface of sperm cells. They can develop in either partner. In men, they typically arise following injury, infection, or vasectomy. In women, they can form through immune sensitisation after repeated sperm exposure.
The relationship between ASA and recurrent pregnancy loss is still being defined, but a 2020 review acknowledged that multiple studies have demonstrated increased miscarriage rates in women with ASA, making it a clinically relevant factor worth investigating in couples with unexplained losses, particularly before proceeding with IVF. (8)
Why a Standard Semen Test Is Not Enough
A standard semen analysis remains an important starting point, but it does not capture the full story. It tells you nothing about fragmentation, methylation, or immune interference. For couples dealing with recurrent pregnancy loss or unexplained infertility, stopping at a basic test means potentially missing a contributing male factor that is both identifiable and, in many cases, treatable.
If you are looking for a more complete picture of sperm health, Sapyen's Complete Analysis covers exactly this ground. It includes core semen analysis together with the Antisperm Antibody Test, the DNA Fragmentation Test, and the SpermEGT™ DNA Methylation Test, which assesses epigenetic abnormalities in sperm that standard pathology cannot detect.
For couples who have experienced miscarriage and still do not have answers, understanding these dimensions of sperm health is a logical, evidence-based next step. The answer to an unexplained loss is not always found on one side alone. Poor sperm health could also be responsible.
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References
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00682-6/abstract
https://academic.oup.com/hropen/article/2023/1/hoad002/7068067
https://www.sciencedirect.com/science/article/pii/S1472648325003918
https://link.springer.com/article/10.1186/s13148-025-02043-3
FAQs
Should couples with recurrent miscarriage consider advanced male fertility testing?
Many fertility specialists recommend considering advanced testing, such as sperm DNA fragmentation, DNA methylation, and antisperm antibody assessments, when recurrent pregnancy loss remains unexplained after standard evaluations.
Can a man have normal semen results but still have fertility-related issues linked to miscarriage?
Yes. Standard semen analysis evaluates sperm count, motility, and morphology but does not assess DNA fragmentation, DNA methylation abnormalities, or antisperm antibodies.
