Sperm Health and Fertility, Miscarriage and Your Chances of Conception
When a couple is trying to conceive, so much of the focus lands on the woman's body. Her cycle, her hormones, her eggs. And while all of that matters enormously, it tells only part of the story. Sperm contributes around half of the genetic blueprint for a baby, and sperm health has a real say in conception, in the quality of an embryo, and even in the risk of miscarriage.
This is one of my favourite conversations to have because it shifts the load. Fertility becomes a shared project rather than something one person carries alone. So let's talk honestly about sperm health, what it has to do with miscarriage, and how it shapes the chances of conception.
Sperm health is half of the equation
To make a baby, a few things need to come together. Healthy eggs, a receptive uterus, and viable sperm with good count, movement, shape, and DNA integrity. If any one of these is off, the whole picture is affected. Sperm is not a minor player. It is one of the three core ingredients.
Here is a reframe I find really helpful. Both eggs and sperm take roughly three months to mature, with sperm development taking around 72 to 76 days from start to finish. That window is the opportunity. The choices made in those three months, around nutrition, lifestyle, and reducing exposures, directly shape the quality of the sperm that turn up at conception. It is one of the most hopeful facts in this whole area, because it means there is something you can actually do.
What does a healthy sperm sample look like?
A standard semen analysis looks at several things. As a rough guide to what is considered a healthy baseline:
• Concentration of more than 15 million per millilitre, though we love to see more.
• Total motility around 40 percent, with progressive motility (sperm swimming forward) above 32 percent, and ideally higher.
• Morphology, the shape of the sperm, around 4 percent normal forms or above, depending on the lab.
One thing worth knowing is that a single semen analysis is only a snapshot of one moment in time. It captures sperm produced over the previous couple of months, so it reflects a window rather than a fixed destiny. That is genuinely good news, because it means the picture can change.
It is also worth holding some perspective on the bigger trend. Research tracking sperm counts over recent decades has found a significant decline, which is part of why preconception support for men has never been more relevant.
The piece that often gets missed: DNA fragmentation
A standard analysis tells us about count, movement, and shape, but it does not tell us about the integrity of the DNA inside the sperm. This is measured separately, often with a test called the sperm chromatin structure assay, which gives a DNA fragmentation index.
Why does this matter so much? Because the egg has to repair any DNA damage the sperm brings with it before an embryo can develop properly. The more damage, the more the egg has to compensate, and that can affect whether an embryo continues to grow. As a general guide, lower is better, with results under 15 per cent considered excellent and results above around 29 per cent considered poor.
The encouraging part is that DNA fragmentation is one of the more responsive markers. With the right support, it can often improve over a span of two to three months, which lines up neatly with that sperm development window.
Sperm health and miscarriage
This is the part many people have never been told. Miscarriage is so often framed as something to do with the woman's body alone, but sperm DNA quality is part of the conversation too.
Where there is a history of recurrent miscarriage, sperm DNA integrity becomes especially worth assessing, with the aim of seeing a low fragmentation index. A few other factors connect sperm health to miscarriage risk:
• Oxidative stress and DNA damage in sperm, which can affect embryo development.
• Nutrient status, with selenium being closely linked to miscarriage because of its role in the DNA within the sperm head, and homocysteine reflecting blood supply and sperm quality.
• Certain infections, which can cause historical DNA damage that lingers even after the infection itself has cleared.
Lifestyle factors weave through all of this. Smoking, including vaping, drives DNA fragmentation and raises miscarriage risk, and notably, it does so even when the female partner does not smoke. Sleep, alcohol, body weight, and exposure to environmental toxins all leave their mark on sperm quality too. Each of these is an area where change is genuinely possible.
Age, timing and the chances of conception
Let's set realistic expectations, because they are weirdly reassuring. Even for a couple with no fertility factors at all, the chance of conceiving in any given month is around one in five. Conception is often a numbers game played over several cycles, not something that happens on the first try, and that is completely normal.
Most couples who conceive naturally within a year will have done so by around the six-month mark. Age plays a role on both sides. For sperm, the highest chance of conception tends to be under 40, with testicular function and sperm quality gradually declining after that. So while the spotlight often falls on the woman's age, the male partner's age and health matter as well.
And when it comes to timing intercourse, the practical advice is refreshingly simple. Unless there is a known sperm count issue, regular intercourse, including daily around the fertile window, tends to support the best chances. If count is a concern, allowing a day in between can help. Either way, this is a shared and very human part of the process.
Please remember this:
Sperm health is not a footnote. It shapes conception, embryo quality, and miscarriage risk, and it is one of the most changeable parts of the whole fertility picture. Because sperm renew roughly every three months, the work you put in during a preconception window has a real chance to show up in the results.
If you are trying to conceive, bringing your partner into the conversation is one of the most supportive moves you can make. Fertility was never meant to be a solo effort, and addressing it together tends to feel a whole lot lighter.
References and source material
This article is written for patient education and draws on the following clinical reference material and named studies. Figures are presented for general understanding and should be verified against the original sources.
1. Levine, H., Jorgensen, N., Martino-Andrade, A., et al. (2017). Temporal trends in sperm count: a systematic review and meta-regression analysis. Human Reproduction Update, 23(6), 646-659.
2. Levine, H., Jorgensen, N., Martino-Andrade, A., et al. (2023). Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries. Human Reproduction Update, 29(2), 157-176.
3. Agarwal, A., Baskaran, S., Parekh, N., et al. (2021). Male infertility. The Lancet, 397(10271), 319-333. (Approximately half of infertility cases involve a male factor.)
4. Evenson, D. P. (2016) and related SCSA literature. Sperm chromatin structure assay and the DNA fragmentation index thresholds used in clinical interpretation.
5. Esteves, S. C., Zini, A., Coward, R. M., et al. (2021). Sperm DNA fragmentation testing: summary evidence and clinical practice recommendations. Andrologia / Translational Andrology and Urology.
6. Jimbo, M., Kunisaki, J., Ghaheri, M., et al. (2022). Fertility in the aging male: a systematic review. Fertility and Sterility. (Paternal age, sperm DNA methylation and pregnancy and perinatal outcomes.)
7. Hechtman, L. Preconception care and fertility lecture and male assessments handout: oocyte and sperm development timelines (sperm approximately 72 to 76 days), semen analysis parameters, DNA fragmentation, miscarriage considerations (selenium, homocysteine) and time to conception guidance.
8. Reproductive Health Clinical Foundations (2025). Spermatogenesis, age and conception, expected time to conception, smoking and miscarriage risk, and DNA fragmentation testing indications.
The Naturopathic Guide to Preconception
A comprehensive, naturopathic guide to preparing your body for conception, pregnancy and beyond.
Preconception care is about so much more than simply “trying” for a baby. The months before conception are a powerful window to support egg quality, sperm health, hormone balance, nutrient status, cycle health and the environment your future baby will grow in.
This guide was created to help you feel informed, prepared and empowered as you begin your fertility journey — with practical tools across nutrition, lifestyle, stress management, toxin reduction, cycle awareness and pathology testing.
Inside, you’ll learn how to support your body through:
Preconception foundations
Understand why the months leading up to conception matter for both partners, and how your daily habits can influence fertility, implantation and pregnancy health.
Fertility-focused nutrition
Learn how to build a Mediterranean-inspired, nutrient-dense diet with the right balance of protein, complex carbohydrates, healthy fats and fertility-supportive foods.
Toxin reduction and endocrine disruptors
Discover how everyday products may impact hormones and reproductive health, with simple swaps to reduce exposure to endocrine-disrupting chemicals.
Stress and reproductive health
Explore the connection between stress, hormones and fertility, with supportive tools to help regulate your nervous system during the preconception period.
Cycle tracking and fertile window awareness
Learn how to track basal body temperature, cervical mucus and key cycle signs so you can better understand ovulation and identify your most fertile days.
Essential nutrients and supplements
Understand the key nutrients involved in egg quality, sperm health, hormone production, implantation and early pregnancy — plus what to look for in a quality prenatal.
Optimal blood test ranges for conception
This guide also includes key pathology markers and optimal preconception ranges to help you understand whether your body is nutritionally, hormonally and metabolically supported for conception and pregnancy — not just whether your results are technically “in range”.
Male fertility support
Because fertility is a two-person equation, this guide also explores how men can support sperm quality through diet, lifestyle and targeted nutrients.
The two-week wait
Practical guidance for staying grounded, calm and supported during the emotional window between ovulation and pregnancy testing.
Whether you are just starting to think about pregnancy or actively trying to conceive, this guide will help you build a strong foundation for your fertility journey using evidence-informed naturopathic care.
Prepare your body. Support your fertility. Feel confident in your next steps.