Researchers at Harvard Medical School, US, have conducted the largest study ever into IVF live births, using data from Boston IVF and Israel Deaconess Medical Centre, in an attempt to quantify the success rate of IVF in both younger and older women. The findings are published in the New England Journal of Medicine.

Typically, outcomes of IVF are reported as pregnancies per IVF cycle, but patients undergoing IVF are more interested in their odds of achieving a live birth over the entire course of treatment. The study concludes that for infertile women under 35, IVF can give them the same level of fertility as their fertile peers, but that IVF cannot reverse the effects of ageing on fertility in women over 40.

Senior study author Dr Alan S Penzias, director of Boston IVF and Professor of Obstetrics, Gynaecology and Reproductive Biology at Harvard Medical School, commented that 'IVF is a mainstay of the treatment of infertility, and it can overcome most causes of infertility in those under 40, but fertility is a function of age. It starts to decline at 27, and the most pronounced decline is over 40'.

The researchers followed more than 6,000 women undergoing IVF, with a total of more than 15,000 IVF cycles completed. The overall live birth rate after six cycles of IVF was between 51 and 72 per cent, with the rate for women under 35 at 65 - 85 per cent. The rates differed because not all women returned for six cycles and, in order to account for those women, the researchers took both a best case scenario (that the women who did not return for treatment all did so because they had had a baby) and a worst case scenario (that none of them had had a baby). The actual number is therefore between the two numbers listed. 

However, the study also noted that live births decreased as women became older, with only a 23 - 40 per cent chance of a woman over 40 having a baby. This is because IVF cannot counteract the effects of aging on a woman's egg supply, and this can only be avoided if a woman uses eggs donated by a younger woman. Dr Penzias commented that, 'one of the sad states of affairs is that there are many women who are not aware that there is an effect of aging', with this misconception being perpetuated by births to older celebrities and the fact that older women generally feel healthy. 

Dr Jamie Grifo, Programme Director for the New York University Langone Medical Centre's fertility clinic, said that there was no test that indicated when fertility began to decline, and urged women to think carefully about their options. He warned women not to 'expect to be able to get pregnant at any time. You don't have to be pessimistic, but the older the patient, the lower the chance of success, unless a couple is willing to consider donor eggs'.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.