At what age does male fertility decrease?

We often talk about the female biological clock, which we know how to inexorably mark the fertility of women while there is too little talk about the male one except for sensational news such as those of famous people who become fathers late in life (see Mick Jagger).

A new study shines the spotlight on the age-related decline in male fertility . In short, males are not fertile forever (we had already talked about it here ) and as the years go by, the possibility of having a child also decreases for them.

When a couple decides to expand their family, they must not only consider the age of the woman (whose fertility decreases after the age of 36) but also that of the man, underestimated for too long.

A man’s age appears to have a ‘substantial impact’ on his ability to have children if the decision is made too late.

I study

The study was conducted by researchers at Harvard Medical School and Beth Israel Deaconess Medical Center and was presented at the Annual meeting of the   European Society of Human Reproduction and Embryology which was held between July 2 and 5, 2017 in Geneva.

The study focused on the outcomes of assisted reproduction treatments which become less effective as partners age.

Data were collected for 15 years, for a total of 19,000 IVF cycles (8,000 couples).

The couples were divided into 4 groups

• under the age of 30,
• aged between 30 and 35 years
• between the ages of 35 and 40
• between the ages of 40 and 42

The birth rate was lower in couples where the female partner was 40-42 years old, which was expected given previous studies.

However, it has been seen that in the younger age groups the age of the male partner directly influenced the couple’s probability of conceiving.

Study conclusions

According to the researchers, the results clearly show that the man’s age is a predictor of the effectiveness of IVF. As male age increases, IVF success rates decrease.

For example, if a woman is under 30 and her partner is between 40 and 42, the birth rate is about 30% lower than for a partner between 30 and 35.

Women between the ages of 35 and 40 to increase their chances of success should have a male partner younger than 30, as they see a relative improvement of 30% compared to women whose partner is between 30 and 35 years old .

Increasing age in men, according to the authors, is also linked to fewer pregnancies, an increase in the time to pregnancy and an increased risk of miscarriage even in natural conceptions .

The reason is not yet clear, although it could be linked to an increase in genetic mutations affecting sperm cells.

The outcome of this study may serve as a reason for men to decide earlier to become parents (often they are the ones who want to postpone pregnancy).