Older men cause infertility

Dr. Randy Morris

Older men cause infertility

Dr. Randy Morris

Couples with fertility problems where the male is over 40 have increased difficulty in conceiving. We know reproductive health is associated with age. Most studies and findings focus on the female age as the determining factor for a successful, healthy pregnancy. While it is true that most miscarriages are due to chromosomal abnormalities and that this is attributed to the age of a female egg, recent findings suggest that the male age has something to do with infertility and miscarriage rates more than previously thought.

Age and Male Reproduction

Men can reproduce at almost any age because they never stop making sperm. Women, on the other hand, are born with all the eggs they will ever have. This means that the eggs age as the woman ages, which can increase the risk for chromosomal abnormalities in an embryo. Although the risk for sperm chromosomal abnormalities does not increase as men age, the potential for DNA damage does increase as men age. Sperm are produced from stem cells in the testicles that must keep dividing. In order for the cells to divide, the DNA in these cells must divide as well. Because the DNA is dividing to a larger extent, the chances for a genetic mutation occurring increase over time. Combine this with older females chances for reproductive success and the outcomes for a successful pregnancy are quite low. A study completed in 2002 found that the risk of miscarriage increased in older men but only when the women were also older.

Other Factors affecting male fertility

Other age related factors could contribute to a male’s sperm production and quality. The incidence of vascular diseases, accumulation of toxic substances, and infections all increase with age. Infections actually have been shown to significantly lower sperm counts when compared to men with normal function. Erectile dysfunction could be another cause of male infertility, as this problem also increases with age.

A number of studies have also found an increase in the risk of several types of diseases in children who are born to older men .

Paternal Effect

At a recent conference for the European Society of Human Reproduction (ESHRE) in Barcelona, Spain, Dr. Stephanie Belloc of the Eylau Centre for Assisted Reproduction presented results of a new study regarding the effect of male age on fertility. The study observed a decrease in pregnancy rates and an increase in miscarriage when the father is over 40. For the first time, a strong paternal effect on reproductive outcomes was discovered. The study followed a large number of intrauterine insemination (IUI) cases. Around 21,239 procedures were studied. It should be noted that most of these couples were treated because of the husbands infertility problems. In an IUI, the sperm are "washed" in a centrifuge to separate the sperm from the seminal fluid. Then the sperm are injected directly into the uterus. The sperm of each partner was examined at the time of the IUI for sperm count, motility (movement), and morphology (shape and appearance). Miscarriage, pregnancy, and delivery rates were also recorded.


Analysis of the data allowed researchers to separate out the male and female effects on pregnancy. Increased maternal age has always been associated with a decreased rate of pregnancy and an increase in miscarriage. This study supported that fact. Only 8.9% of women age 35 and older achieved pregnancy while in younger women, 14.5% were successful in getting pregnant. The surprising factor was that men over 40 had a negative effect on pregnancy rates and it seemed to be attributed to an increase in miscarriage rates. Up until now, there was no clinical proof determining that older males contributed to infertility. Older men generally, take a longer time to conceive but miscarriage rates were never attributed to older male age. Conclusion Because the numbers of couples observed in this study is so large, it enables researchers to come to firm conclusions. This data could be essential in the decision for couples to wait to start a family or begin sooner. This data was obtained only in IUI patients. Other research shows that in patients undergoing more invasive procedures like IVF and ICSI where sperm is injected directly into the egg, male age was not as big of a factor. While more invasive, the treatments are also more effective. The current study recommends using these treatments in couples if either the male or female is over 40. While these methods are not guaranteed, they are the best choices for achieving pregnancy and preventing miscarriage in couples with older men.