A recent American study considers the impact of the age of the father on the health of babies at birth. Less intuitively, it also notes the influence of the age of the father on the mother’s health during pregnancy.
Masculine fertility: The age factor should not be neglected
The question of the age of paternity is less covered in the media than the age of maternity. On the question of fertility, the term “biological clock” is most often associated with women. Biologically, the notion of “ovarian stock” has no direct equivalent for masculine fertility. In fact, spermatogenesis is a more continuous process, which diminishes slowly with age. Cases of very late paternity are reported in the media, such as the famous actor Robert de Niro, at 80 years of age at the beginning of the year.
The bioethics law, which authorises self-preservation of gametes for no medical reasons, in September 2021 established “limits” by decree which take into account the biological differences and realities. It is therefore authorised for men and for women from their twenty-ninth year, and it remains possible up to 37 years of age for women, and 60 years of age for men.
In the recent debates on the falling birth rate in France, the increasing age of the mother for her first child has regularly been mentioned as an explanatory factor. According to INSEE, the French statistics institute, the average age of the mother for her first child has increased from 26.5 to 31 years old over the last fifty years. There is less mention that the age of the father for the first child has also increased. One of the most important factors is “mechanical”.
It is linked to the age differential in couples. INSEE, in a study dated 2016, had found that on average in a couple, the man was 2.5 years older than the woman.
The question of the impact of the father’s age on the couple’s fertility has been the subject of several studies. One of them was conducted by doctors at Toulouse hospital in 2012. In their conclusion, they stated: “Another key conclusion is the impact of the father’s age, just as the mother’s age, is an important and major factor to be considered. This should encourage couples to try to start planning to have children earlier.”
What is the impact of the father’s age for the child and for the mother ?
A recent study released last August in the United States looked at the “socio-demographic trends and the perinatal results in fathers over 50 years of age”. The authors consider that “the age of fathers at the birth of their child is increasing, with ever more births being attributed to older fathers “. The percentage of paternities “at an advanced age” remains low: 1.3% of births, but with an overall trend: 18% increase since 2011. 500,000 babies in the United States were born between 2011 and 2022 of fathers over 50.
The study concludes on the statistically significant impact of the advanced age of the father on the child and even on the mother.
For example, compared with a group of fathers aged between 30 and 39 years, for fathers aged between 50 and 59 years, the risk of a premature birth increases by 16%. The risk of a low birth weight also increases by 14%. Finally, the risk of gestational diabetes for the mother also increases by 13%. The risk of premature birth even rises to 21% if the father is over 70.
The authors also reported that resorting to artificial procreation techniques was twice more likely in the case of older paternities compared with the group of fathers aged between 30 and 39. This observation is probably linked to the fact that masculine fertility also declines with age.
Alongside these negative factors identified in the study, the authors note that positive factors may also exist such as” financial stability, the improvement of nutritional and educational possibilities”.
The delaying of births to an older age is a serious trend in our society, whether for mothers of for fathers.
The impact on fertility of the age of the man and the age of the couple (i.e. the man and the woman) are less documented than the age of the woman alone. According to the 2022 Report on the causes of infertility, “The deleterious effect of the age of the man on his fertility is also beginning to be recognised by specialists in reproduction, but it remains little apprehended by the general public. Sperm may deteriorate (in number, mobility, morphological or genomic anomalies). Age diminishes the concentration and quality of the sperm.
The increasing risk of masculine infertility due to age is moderate and very gradual from 40 years of age, but very definite from 50.
The statistical results of this new study underline the importance of informing the general public on the age factor and its impact in terms of both fertility and birth rate.