Scientists have discovered the reason why women find it difficult to conceive later in life - they have used up 90 per cent of their "ovarian reserve" by the age of 30.
The new research by the Univeristy of St Andrews and Edinburgh University is the first to colate the actual decline of the "ovarian reserve" - the potential number of eggs women are born with - from conception to the menopause.Oh dear. I haven't read the original research, maybe it does demonstrate what the authors claim, but not on this evidence. Given that the average woman has 4-500 menstrual cycles in her lifetime then losing 90% of these eggs hardly makes a dent. Over 90% of eggs formed in gestation are lost by birth, does this explain why newborn and pre-pubescent children are infertile?
It shows that on average women are born with 300,000 potential egg cells but this pool declines at a much faster rate than first thought.
By the age of 30 there is only 12 per cent left on average and by the age of 40 just three per cent. Dr Hamish Wallace, the co-author, said: "Our research shows that they are generally over-estimating their fertility prospects.
The researchers said many women make the mistake of thinking that because they are still producing eggs that their fertility remains constant. But this new research shows that it delcines rapidly.