Female age is a more decisive factor than male when it comes to fertility. The ability of women to become pregnant – naturally or assisted – and give birth to a healthy child decreases by 46% from 30 to 40-42 years, while in men the chances of being fertile fall by 20% in the same period.
But a study by the Beth-Israel Deaconess Clinical Center in Boston and Harvard Medical School has found that, in the case of in vitro fertilization (IVF), the chances of successful treatment also decrease considerably as the number of patients increases. age of the male member of the couple, something that has been found in cases where the woman is younger than the man.
The research analyzed 19,000 IVF cycles carried out in 7,753 couples between 2000 and 2014. The women were divided into age blocks (less than 30, 30 to 35, 35 to 40 and 40 to 42). In the case of men, the same was done, and a segment of those over 42 years of age was added.
The results showed that, unsurprisingly, the lowest success rate was found in couples in which the woman was 40 to 42 years old, a group in which male age had no influence. However, in the other age bands, the viability of assisted reproduction was affected by the age of the man. The higher this, the lower the chance of pregnancy.
According to Dr. Laura Dodge, one of the authors of the study, “in women between 30 and 35 years of age, having a partner older than them reduces their chances of pregnancy by 11%.” The mechanisms that explain this decline in male fertility over time are unclear, although the poorer quality of semen in those over 40 appears to be the main cause.
