When it comes to fertility, age isn’t just a number; you can’t outrun the biological clock. It’s (yes, still) one of the biggest predictors of reproductive outcomes. This doesn’t mean you won’t get pregnant if you’re on the north side of 35, but it does mean that as you get older, your chances of conception decrease. But don’t panic. Learn more about how age impacts fertility for both males and females, and even more importantly, how to slow down some of that aging process.
Why does age impact fertility?
Both eggs and sperm are cells and, as we age, biological and environmental changes contribute to cellular decline, including changes in DNA replication, increased oxidation, the stability of genetic material, and changes to cellular signalling, to name just a few reasons. These changes affect everything from degenerative diseases to wrinkles and grey hair, and fertility.
Why does age affect fertility for females?
As females age, they experience a decline in both egg quality (how healthy) and egg quantity (how many). Generally, female fertility begins to decline around age 32 and more rapidly after age 37. By the age of 40, relative fertility is about half of that compared to females in their 20s to early 30s, which is considered peak fertility.
You can see this decline by taking a look at the probability of conception each cycle, based on maternal age:
Egg quantity and age
You’re born with all of the eggs you will ever have, and this number decreases with age. By the time you reach menopause, your pool of eggs is nearly depleted. The number of eggs and the rate at which they decline can’t be changed or slowed, though it can be tracked by assessing ovarian reserve (how many eggs you have left) with tools like FSH tests (which can be done at home) and antral follicle counts (done in a clinic).
Egg quality and age
Egg quality also decreases with age, thanks to increased oxidative stress and DNA damage, mitochondrial dysfunction, and increased chromosomal abnormalities. Each of these impacts egg quality (which in turn can impact embryo quality) and contributes to an increased risk of miscarriage. The good news? There’s room for improvement when it comes to egg quality—or at least there’s room to slow down the effects of cellular aging (more on that in a sec).
Learn More About Egg Quantity vs. Egg Quality →
How does age affect fertility for males?
Spoiler alert: Age also impacts male fertility. Sperm health does decline with age—the same principles of cellular aging apply here, too.
One of the main age-related reasons sperm health declines is an increase in sperm DNA fragmentation. Studies show that sperm DNA fragmentation increases with age, particularly over the age of 40, likely due to changes in spermatogenesis (production of sperm) and increased oxidative stress. This DNA damage can impair the sperm's ability to fertilize an egg and can also contribute to higher rates of miscarriage and genetic abnormalities.
Testosterone production and semen parameters like sperm concentration, motility, and morphology also change; older males tend to have lower sperm counts and reduced motility, which can decrease the likelihood of successful fertilization. This is likely relates to age-dependent changes in the testicular environment, including increased reactive oxygen species (ROS) production, which can damage sperm cells.
Can you reverse or undo the effects of aging on fertility?
Unfortunately, there’s no way to stop the effects of aging on fertility. But, certain lifestyle changes and supplements can support both male and female fertility and potentially mitigate some age-related declines. Here’s what helps:
1. A Mediterranean-style diet:
Prioritizing a Mediterranean diet, which is rich in vegetables, fruits, fibre-filled grains, and healthy fats, has been associated with improved fertility outcomes. This can also help maintain a healthy body weight, which is crucial, as both obesity and being underweight can negatively impact fertility
2. Antioxidants—specifically CoQ10
Antioxidants such as Coenzyme Q10 (CoQ10) have shown promise in improving egg quality and increasing pregnancy rates in females with diminished ovarian reserve. Both eggs and sperm require a lot of energy, and CoQ10 (and another antioxidant, NAC) are the preferred fuel source. CoQ10 supplementation can also improve sperm concentration, motility, and morphology, and has been associated with higher pregnancy rates, for both spontaneous conception and IVF. Antioxidants (which also include Vitamins C and E, Beta-Carotene, and Zinc) are a powerful way of decreasing the oxidative stress that can impair both eggs and sperm.
What is CoQ10—and Why Do I Need It? →
3. Fertility-supporting supplements:
Vitamin D, Folic Acid, and Omega-3 Fatty Acids can also benefit reproductive health and fertility. Folic Acid isn’t just for pregnancy—it’s particularly important to support normal DNA replication and integrity in aging eggs and sperm (that's right, Folic Acid has benefits for men, too).
4. Lifestyle changes
Reducing stress, avoiding smoking and excessive alcohol consumption, and engaging in regular exercise can also support reproductive health at any age.
4 Simple Lifestyle Changes to Boost Your Fertility →
While you can support your fertility and reproductive health, you can’t fully reverse the effects of aging on ovarian reserve, egg quality, or declining sperm health. Thinking about your fertility sooner—whether that means growing your family earlier, egg freezing or sperm preservation, or adjusting your supplements and lifestyle to focus on fertility support—can make all the difference in your journey.
