Tick Tock...

Dr Kirsty Horsey

Progress Educational Trust

08 May 2002

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[BioNews, London] The results of a study published in the May issue of the journal Human Reproduction show that both male and female fertility begins to decline earlier than was previously believed. A woman's fertility starts to decline in her late 20's (at around 27 years old), and not in her 30s, as wisdom had it.

The study, undertaken by researchers from the US National Institute of Environmental Health Sciences and the University of Padua, Italy, looked at 782 healthy couples using natural family planning methods to avoid pregnancy. Lead researcher, Dr David Dunson, believes that this is the first such study to show a decline in women's fertility before the age of 30. But he reassured women that the results indicate that it would take longer for a woman in her late 20s or early 30s to become pregnant, rather than her having an overall lower chance of ever becoming pregnant.

The study also showed that male fertility begins to decline when men reach their late 30s. Dunson said that 'the day-specific probability of pregnancy declined for women from the late 20s onwards, being around twice as high for women aged 19-26 as for women aged 35-39. When we controlled for the age of women, we found that fertility was significantly reduced for men aged over 35.'

The findings are not a complete shock, as it has long been assumed that fertility declines gradually with age through the reproductive years. What this study shows is that the decline begins a little earlier than was thought.

Reproduced with permission from BioNews, an email and online sources of news, information and comment on assisted reproduction and genetics.