Recent figures released by the UK fertility regulator, the Human Fertilisation and Embryology Authority (HFEA), show a tenfold plus increase in women over 40 seeking fertility treatment using their own eggs. The number of women over 40 seeking fertility treatment using donated eggs is not know, but could run into several hundred.

In 1991, 596 treatment cycles were performed on women between the ages of 40-45; by 2006 this figure had risen to 6,174. According to HFEA figures, in 2006 women aged 40-45 accounted for 15.5 per cent of all treatment cycles performed in the UK, compared to just 9.2 per cent in 1991. Despite this massive increase of older women seeking fertility treatment, the live birth rate among women over 40 remains relatively low at just 11.8 per cent, compared to 7.6 per cent in 1991.

The HFEA has not released a social profile of women in their forties seeking IVF. The reasons, however, are thought to be societal rather than medical and concerns have been raised by the massive increase in demand for treatment. Dr Allan Pacey, secretary of the British Fertility Society told the BBC: 'The data from the HFEA register would seem to reflect the general trend of couples in the UK to wait until they are older to have their families. But it is dangerous to think that because IVF is now so widely available that couples can delay their attempts to start a family because IVF is some kind of safety net'.

Later pregnancies represent a much higher risk to both the mother and child, than pregnancy in a woman's 20s and earlier 30s. Women over 40 have a greater chance of miscarriage, and there is an increased likelihood of ectopic pregnancy, premature birth, neonatal death and birth defects.

Angela McNab, Chief Executive of the HFEA told the Times: 'It may well be that one of the messages we need to concentrate on is reminding women about their biological clocks, and the increasing difficulties they will have having a baby after 40, and especially after 45'.