The age-related decline in fertility for women is very well known, as well as the fact that after menopause, women’s fertility comes to an abrupt halt. But what about men? There are plenty of anecdotes about men fathering children into their 70s and even their 80s. We may have the impression that men stay fertile for as long as they’re sexually active. This is not the case. Compared with women, the decline in male fertility rates is more like a gentle downhill slope than the proverbial cliff edge, but it’s still there.

When does male fertility start to decline? In this article we examine the evidence showing when and how male fertility declines. This includes age-related reductions in sperm count, sperm motility and changes to the overall health and reproductive potential of sperm as men become older.

At what age does male fertility start to decline?

Even though there is no sudden cessation of fertility for men, the age at which fertility starts to decline is remarkably similar for both sexes. A study carried out in Israel’s Soroka University analyzed the relationship between age and measures of semen health in men with a normal semen concentration. It found a statistically significant inverse correlation between a man’s age and semen volume and sperm quality. The top measures were scored by men between the ages of 30 and 35 years. The most significant reduction on all measures occurred after the age of 55.

Another study carried out across eight European centers looked at the combination of the age of the man and the woman. It found, as expected, that age was an important factor in rates of conception for women. Rates were highest for women aged 19 to 26, slightly lower for women between 27 and 34, and then lowest for women of 35 to 39 years. For men, however, the decline in fertility started to show around the late 30s, across the board. Looking at the combination of ages, the study found that for a woman between 35 and 39, if her partner was five or more years older, successful conception and pregnancy rates dropped by around half, to only 15%.

How does male fertility decline?

Several factors combine to produce male fertility decline with age. These even include frequency of sex. This is because prolonged abstinence from sex also has the effect of reducing semen quality. On the contrary, frequent sex creates healthier sperm.

• Sperm count: An American study confirmed that sperm count does decline with age. It drops from around 107 million for men in their 20s, to half that amount, at 35.5 million for those in their 50s. However, any sperm count over 20 million, as long as the motility and quality is good, is still considered above the level of sub-fertility. The sperm count itself is probably less of a factor in declining fertility than sperm motility and sperm quality.
• Sperm motility: Motility is the measure of how well sperm ‘swim’. Here we see a significant decline from a peak at age 25 to a much lower level after the age of 55. In fact, the number of sperm with good motility declines by 54%, over half, between the ages of 35 and 55. However it’s worth remembering that men, unlike women, continue to produce sperm all of their lives. Therefore, in spite of the decline in sperm count and motility, the possibility of fathering a child, while it may reduce, never becomes zero.
• Overall sperm health: A further similarity in declining fertility between men and women relates to the quality, as well as the quantity, of their reproductive cells, the gametes. These are the ovocytes in women and the sperm in men. Just as the older a woman is, the more likely her remaining eggs are to have some age-related decline in genetic quality. The same applies to men and the quality of their sperm. These genetic defects can be the cause of decreased fertility. But also there can be increased chance of miscarriage, a higher chance of some birth defects and a higher likelihood of stillbirth.

Can fertility treatment help men with declining fertility?

There are a few ways in which fertility treatment can help a man with a low sperm count or low sperm quality for whatever reason. Each patient is different. Any recommended treatment would also depend on the fertility status of your partner. Nevertheless, in general the two main ways that treatment could help would be either artificial insemination (AI) or the well-known assisted fertility treatment in vitro fertilisation (IVF), often with the addition of intracytoplasmic sperm injection (ICSI). Both treatments include a process of sperm optimization which increases the chance of conception. You can learn more in our article ‘What can be done when sperm motility is low?’.

Sperm optimization

The difference between trying to conceive naturally and either of the treatment options above is that your sperm sample can be prepared, and optimized, in advance. This is achieved by the andrology laboratory in our IVI clinics. During the process, our andrologists concentrate the healthiest sperm by eliminating those with poor morphology or motility. This means the remaining sperm is healthy and has the best chance of reaching and penetrating the egg.

IVF with ICSI

IVF uses sperm optimization to boost the chances of conception. However, whenever we use ICSI in the process, the sperm get even more help. In this technique, our embryologists select a single healthy sperm and microinject it directly into the egg. A successful pregnancy is not guaranteed. This method though really removes most of the element of chance to further increase the likelihood of egg fertilisation.

Contacting us at IVI

Would you like to know more about the techniques available to help with declining fertility? Or about any other issue around fertility treatment? Do get in touch with us as IVI.