A brand new review, published today, of almost 19,000 IVF treatment cycles has put paid to myths about ‘ageless’ male fertility.
Men, unlike women, do not experience menopause or a predictable and detectable decline in their fertility. For this reason, female age has been, to date, the dominant factor in predicting a couple’s chance of conception, whether natural or assisted.
Men, age and fertility: the story so far
The large majority of research on age-related infertility has concentrated on women, with much advice given on when women should start building a family. Large studies have shown that couples hoping for a one-child family should start trying to conceive when the female partner is 35 years old or younger, with IVF as an acceptable option, for two children the latest starting age would be 31 years, and for three children 28 years.
A large population study in the UK also found that non-assisted conception during a twelve-month period was 30 percent less likely for men aged over 40 than for men younger than 30. There have been several explanations for this age-related decline in fertility – notably, a decline in sperm count and quality, and an increase in DNA fragmentation. Increasing male age is also associated with a greater incidence of medical conditions, which can affect fertility.
A few studies have found that the chance of natural conception can be affected by the age of the male partner, particularly in the genetic health of sperm cells, but the celebrity examples of Charlie Chaplin (his youngest son was born when Chaplin was 73) and Steve Martin (first-time dad at the age of 67) have kept alive the notion that male fertility goes on forever.
Ground-breaking
Brand new research, the results of which are due to be presented today at the 33rd Annual Meeting of ESHRE in Geneva, shows quite clearly that live birth outcome is clearly affected by the age of the male partner. Investigator Dr Laura Dodge of Harvard Medical School in Boston, also found that – in certain younger female age groups where the effect of age is less potent – the chances of live birth can be reduced by the male partner’s increasing age.
The large-scale study was an analysis of all IVF cycles performed at a busy IVF centre in the Boston area between 2000 and 2014, with a total of almost 19,000 cycles performed in 7753 couples. The female partners in these cycles were categorised according to four age bands: under 30, 30-35 years, 35-40 years, and 40-42. Men were placed into the same four age bands, with an additional band of 42 and over.
As expected, the cumulative live birth rate (this refers to the chance of delivery of a live baby after one or more cycles of treatment – in this case measured from up to six cycles of treatment) was lowest in those couples where the female partner was in the 40-42 age band. However, within the other bands of female age, the live birth rate was significantly affected by male partner age and was found to decline as the man grew older.
Increased risk of miscarriage
Commenting on the surprising results, Dr Dodge noted that in natural conceptions increasing male age is associated with a decreased incidence of pregnancy, increased time to pregnancy, and increased risk of miscarriage. The mechanisms, she added, are unclear but may include increased DNA damage in sperm, and alterations in sperm that affect fertilisation, implantation, or embryo development.
“Generally, we saw no significant decline in cumulative live birth when women had a male partner the same age or younger. However, women aged 35-40 did significantly benefit from having a male partner who is under age 30, in that they see a nearly 30 percent relative improvement in cumulative incidence of live birth when compared to women whose partner is 30-35 – from 54 percent to 70 percent.
“Where we see significant decreases in the cumulative incidence of live birth is among women with male partners in the older age bands. For women age 30-35 having a partner who is older than they are is associated with approximately 11 percent relative decreases in cumulative incidence of live birth – from 70 percent to 64 percent – when compared to having a male partner within their same age band.”
Can older men improve their fertility?
So, what can men with younger female partners do to compensate for this age effect in IVF? Dr Dodge says that it’s hard to say without knowing the precise mechanisms involved:
“Most preconception advice for men focuses on semen quality, though studies suggest that this likely cannot fully ameliorate the effects of male reproductive ageing. So in the absence of clear evidence of the mechanisms, the best pre-conception advice we can offer is to maintain a healthy lifestyle.”
