During IVF conceptions, age of both man and woman matters equally and it is not just a woman’s age that can cause a problem in pregnancy, researchers have found through a study.

The findings are based on almost 19,000 IVF treatment cycles in the Boston region between 2000 and 2014 wherein a decline in success rate with increase in male partner age was found. Scientists point out an independent effect of male age on the cumulative incidence of live birth.

The female partners in these cycles were stratified according to four age bands – under 30, 30-35 years, 35-40 years and 40-42.

Men were stratified into these same four age bands, with an additional band of 42 and over.
As expected, the cumulative live birth rate (measured from up to six cycles of treatment) was lowest in those couples where the female partner was in the 40-42 age band, and in this group the age of the male partner had no impact, demonstrating the dominant detrimental effect of female age.

However, within the other bands of female age, the cumulative incidence of live birth was significantly affected by male partner age and was found to decline as the man grew older.
For example, in couples with a female partner aged under 30, a male partner aged 40-42 was associated with a significantly lower cumulative birth rate (46 percent) than a male partner aged 30-35 (73 percent).

Similarly, in couples with a female partner aged 35-40 years live birth rates were higher with a younger than with an older male partner.

For women between ages 30 and 35, having a partner who is older than they are is associated with approximately 11 percent relative decreases in cumulative incidence of live birth when compared with having a male partner within their same age band, authors of the study note.

In natural conceptions increasing male age is associated with a decreased incidence of pregnancy, increased time to pregnancy, and increased risk of miscarriage, researchers noted.

The mechanisms, she added, are unclear but may include impaired semen parameters, increased DNA damage in sperm, and epigenetic alterations in sperm that affect fertilisation, implantation, or embryo development.