Men who believe they can put off fatherhood and rely on IVF to have children have been given a reality check by research which suggests their fertility may drop off in a similar way to women before the menopause.
UK researchers found men in their fifties saw their chances of having a baby through IVF fall by a third compared to men in their mid-thirties. Women experience the menopause, on average, at the age of 51 after they stop producing eggs, but experts warn that a gradual build-up of damaging mutations in men’s sperm may produce a comparable effect.
This mechanism is thought to explain why rates of developmental disorders like autism are slightly higher in children who have older fathers, and researchers say more needs to be done to make men aware their fertility in old age is not guaranteed.
“Men’s sperm seems to be unaffected by their age right up to the age of 50, which is when there is a significant decline,” said Dr Guy Morris from the Centre for Reproductive and Genetic Health, which led the research along with University College London (UCL).
“Women lose the function of their reproductive organs when they go through the menopause. In men, the quality and quantity of sperm production declines with age and this seems to have a significant effect after the age of 50.”
Rod Stewart was 66 when his eighth child, Aiden, was born, and the silent film actor Charlie Chaplin had children into his seventies. But experts said these cases may be more down to the relatively wealthy men having much younger wives, and called for an awareness campaign to correct the myth that men can reproduce successfully into old age.
The UCL team analysed records from nearly 5,000 IVF cycles at the Centre for Reproductive and Genetic Health in London over the past nine years. The data, spanning 4,271 men, found that half of men under the age of 35 were able to get their partners pregnant, but by age 41 to 45 this had fallen to 35.1 per cent, and at age 51 success had slumped to just 30.5 per cent.
Previous studies have shown men’s chances of conceiving naturally drop off with age, but this study is one of the largest to look at success in IVF.
Professor Adam Balen, chair of the British Fertility Society Fertility Education Initiative, said: “We want to see fertility taught as part of the relationship and sex education curriculum and have been successful in getting it included. Young men need this information – they need to know that they won’t necessarily remain fertile their whole life and are more likely to have problems as they age.”
The findings were presented at the annual meeting of the European Society of Human Reproduction and Embryology in Vienna. However, experts believe there could be pressure to start applying these findings immediately.
There is currently no cut-off age for men to access IVF, though guidelines recommend that women should not be offered fertility treatment after the age of 42. Age could be added to weight, and a host of other criteria used, to restrict IVF access in England as budgets are squeezed.
“Commissioners want to see an upper age limit for men going to IVF as yet another way of rationing,” said Professor Allan Pacey, a fertility expert from the University of Sheffield. “I don’t think that’s justified because it’s a completely different biological mechanism – but commissioners want a number.”
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