Doctors are worried that celebrities who have children in their 40s are giving women false hope about motherhood.

Many who parade their ‘Miracle babies’ will not have gotten pregnant naturally but will often have used IVF or donor eggs.

Failure by celebrities not to make this public means their fans fail to realise that fertility declines dramatically after the age of 37.

The issue was thrown into the spotlight by a study showing that at 44 it is almost 20 times harder to get pregnant than at 39.

The rapid speeding up of their biologically clock means women in their mid-40s have only a 1.3 percent chance of the treatment working.

But at the ages of 38 or 39, the success rate is 23.6 percent. The point at which fertility starts to fall significantly is 38, according to researcher Marta Devesa.

“I’m amazed that even the most well-informed of women still don’t realise just how much age affects fertility,” said Professor Charles Kingsland of the Hewitt Fertility Centre at Liverpool Women’s Hospital, UK.