Fertility treatment technique 'could cause IVF failure, birth defects'

4th July 2011 — Older women undergoing fertility treatment might face extra risks of IVF failure and the development of birth defects such as Down's syndrome as a result of ovarian stimulation, experts have suggested.

Ovarian stimulation involves injecting a woman with medication to increase the number of eggs she produces in her ovaries in order to boost the chance of IVF treatment succeeding.

Chromosome abnormalities

However, Professor Alan Handyside, Director of The London Bridge Fertility, Gynaecology and Genetics Centre in London, and colleagues from eight countries, say there is a possibility that ovarian stimulation may be responsible for causing chromosome abnormalities. They say these might result in IVF failure, miscarriage and sometimes abnormalities such as Down's syndrome.

The research was based on tests involving 34 couples undergoing IVF treatment.

One IVF expert is cautioning that the research is at a very early stage.

Stockholm conference

In a paper being presented to the European Society of Human Reproduction and Embryology (ESHRE) conference in Stockholm, Sweden, the researchers suggest that the fertility treatment technique might exploit weaknesses in the way that the woman's chromosomes are glued together.

Handyside and his colleagues suggest that ovarian stimulation may be disturbing the process by which cells divide to form eggs because, in women over the age of 35, chromosomes are becoming unglued prematurely — particularly smaller ones like chromosome 21 which is involved with the development of Down's syndrome.

Improving treatment

"The results of such research should enable us to identify better clinical strategies to reduce the incidence of chromosome errors in older women undergoing IVF," Handyside says in a statement.

Co-author Professor Joep Geraedts from the Department of Genetics and Cell Biology, Maastricht University, says in a statement: "We also believe that our research will help identify women who want to have their own offspring but have practically no chance of doing so that we can advise them to use donor oocytes [cells from which eggs develop]." Geraedts continues:  "This in itself is already a big step forward that will aid couples hoping for a healthy pregnancy and birth to be able to achieve one."

'No proof'

Stuart Lavery, Consultant Gynaecologist and Director IVF Hammersmith, London, cautions that the research is at a very early stage. "We don't know that it is the process of stimulation that is causing this risk," he tells us. "The Handyside paper has found some additional genetic risks that were not appreciated before, but it's only a hypothesis — with no proof — that it is the process of stimulation that's causing it."

Lavery says more research is needed. "The study suggests that the risks of chromosomal disorders may be higher in fertility treatments than in nature. We now need to examine whether there is a higher incidence of Down's through ovarian stimulation."