Scientists have found further evidence to suggest that, like women, fertility drops in men as they age, heard delegates at the annual meeting of the European Society of Human Reproduction and Embryology. The research, led by Dr Stephanie Belloc of the Eylau Centre for Assisted Reproduction in Paris, France, said that the results - the first to show such a strong paternal effect on pregnancy and miscarriage rates - will have important implications for couples wanting to start a family.
'I think it's important to consider not only the woman, but both members of the couple in natural conception but also in assisted reproduction', Belloc told the Times, adding: 'We believe that the use of IVF should be suggested to infertile patients where either party is over 35 years of age'.
The researchers recorded rates of pregnancy, miscarriage and birth in 12,000 couples undergoing fertility treatment in the form of intrauterine inseminations (IUI), where sperm is injected into the woman's uterus while she is ovulating. They also examined the quality and quantity of the sperm, including their ability to swim, size and shape.
The results showed that, independent of the woman's age, the chances of miscarriage rose from 16.7 per cent if the man was 30-35 years old, to 32.5 per cent if he was over 40. Although the impact of the female 'biological clock' on fertility has been widely studied, this is the first time that such a strong paternal effect on reproductive outcome has been shown, said Belloc. 'Some recent studies have established a relationship between the results of IUI and DNA damage, which is also correlated with is also correlated with a man's age, suggesting that it might be an important factor, but until now there was no clinical proof', she said.
