It is a well known fact that people are waiting longer to have children. The average age of women having their first child has increased from 21.4 years in 1970 to 26.3 years in 2014. The average age of men having their first child was even higher, at 32.4 years in 2010. In fact, of the men having their first child, those who were age 40 years or older increased from 1 in 11 in 1996 to 1 in 7 men in 2010.
What exactly constitutes “advanced paternal age” has never been officially defined, but most sources tend to use the cut-off of 40 years and older. Since so many men are now waiting longer to start a family, questions arise regarding whether there are associated negative implications, with decreased fertility potential as well as an increased risk of health problems in the resulting offspring. An example of the growing importance of advanced paternal age is illustrated by six articles being published in the February 2017 edition of the journal Fertility and Sterility devoted entirely to the subject. What follows is a summary of the latest findings and management recommendations for older men considering starting (or continuing) down the road to fatherhood.
Fertility Potential
In general, fertility potential in men inevitably decreases with age during adulthood, but this decrease usually occurs at a significantly later age then for women. There are many well-known cases of older men successfully establishing pregnancies naturally, with a recent case-in-point being the venerable Mick Jagger fathering his 8th child in 2016 at the age of 73. Anecdotal cases also exist of men in their 80’s and even 90’s successfully impregnating their partners naturally. However, for most of us mere mortals, our semen parameters start to decline in our mid-30’s, but good fertility potential is usually maintained until our late 40’s and even early 50’s.
A wide variety of reasons explain this decrease in fertility potential with age, including changes in hormone levels, sexual dysfunction, increased body fat, accumulated genetic mutations in the spermatic germ cells, medication side effects, and various chronic diseases that can affect fertility (such as diabetes mellitus and hypothyroidism). Most studies of semen analysis parameters in older men show decreases in ejaculate volume, sperm counts, motility, and morphology with time. Elevated levels of sperm DNA fragmentation have also been noted to increase with age in most men. These changes can decrease the chances of establishing a successful pregnancy both naturally and in conjunction with female fertility treatments such as IUI (intrauterine insemination). For couples are who are successful at conceiving naturally, an increased time to pregnancy has also been identified when the man is older. In couples utilizing in vitro fertilization (including ICSI), success rates can also be impacted negatively by advanced paternal age, especially in men with baseline lower sperm counts.
The bottom line is that most men in their 40’s and even 50’s retain good fertility potential and will not have significant problems establishing a pregnancy. However, older men are at an increased risk for having male factor fertility issues which can hinder their ability to conceive.
Health Risks in the Offspring of Older Men
It must be noted that the vast majority of babies born to fathers who are in their 40’s and 50’s are completely healthy. However, studies have consistently shown that the overall risk of pregnancy problems and/or health issues in the offspring of older men is higher compared to that of younger dads. In couples who are successful at establishing a pregnancy, the risks of having a spontaneous abortion or a stillbirth increase if the man is older. Studies have shown that rates of certain health problems (such as autism, schizophrenia, and Down Syndrome) are also increased in situations of advanced paternal age. A number of rare chromosomal disorders are also seen in higher levels in the children of older dads, including achondroplasia (dwarfism), osteogenesis imperfecta, Marfan Syndrome, and neurofibromatosis, among others. Birth defects (such as cleft palate and club foot) are also seen more frequently in the children of men who are older.
The bottom line is that although the rates of health and/or chromosomal problems are significantly higher in the children of older dads, the absolute number of babies born with these problems is still quite low (at least for men in their 40’s and 50’s).
Summary
The reality is that men are increasingly likely to begin starting their families at an older age, and this trend is likely to continue due to the prevailing social and economic pressures that are associated with modern society. Most of these men will not have problems in establishing a pregnancy and the majority of their children will be completely normal and healthy. However, older dads should recognize that they are at a higher risk of having problems with sperm quality, and may want to check semen analysis testing earlier if they are having problems establishing a pregnancy (maybe at 6 months, instead of the typical 12 month recommendation). As for health screening of the baby, a variety of fetal screening mechanisms exist for detecting abnormalities, such as routine ultrasounds, triple/quad blood testing, chorionic villus sampling, amniocentesis and percutaneous umbilical cord sampling. Greater consideration could be given to more aggressive screening in pregnancies achieved by older men. For couples undergoing IVF, advanced maternal age is one of the current indications for preimplantation genetic diagnosis or screening (PGD/PGS). Advanced paternal age is not a current indication for these evaluations, but these recommendations may change in the future as more research data accumulates, and a conversation about this option with your reproductive endocrinologist is never a bad idea.
For more information on advanced paternal age and its relationship to male fertility, please visit the link below on the Male Infertility Guide website:
https://www.maleinfertilityguide.com/older-dads-and-fertility