It has long been known that the older a woman is when she conceives, the more likely her chances of having a baby with Down’s syndrome.
Doctors originally thought the chromosomal abnormalities were related to the age of the egg, but experts now say it could be a result of the IVF treatments older women were receiving.
As Michelle Roberts reports for BBC News, UK researchers who studied 34 couples think drugs used to ready ovaries for IVF can disturb the genetic material of the eggs.
All of the women in the group were older than 31 and had been given drugs to make their ovaries release eggs ready for their IVF treatment. Researchers studied their fertilized eggs and found genetic errors that could cause the pregnancy to fail or the baby to be born with a genetic disease.
A closer look at 100 of the faulty eggs revealed that many of the errors involved a duplication of coiled genetic material, known as a chromosome. Often, the error resulted in an extra copy of chromosome 21, which causes Down’s syndrome. But unlike “classic” Down’s syndrome which is often seen in the babies of older women who conceive naturally, the pattern of genetic errors leading to Down’s in the IVF eggs was different and more complex. And this led the researchers to believe that it was the fertility treatment that was to blame.
UK fertility expert Mr Stuart Lavery says “It’s a little unclear as to whether it’s the medication itself that is affecting the egg quality or whether it’s the medication that is just forcing the issue and allowing eggs that nature’s quality control system would have otherwise excluded, to arise.”
The findings were presented at the European Society of Human Reproduction and Embryology’s annual conference. Doctors say more research is needed to confirm their suspicions. If more tests back up their suspicions then it would mean that doctors should be more cautious about using these treatments.
The researchers believe their work could also help identify which women might be better off using donor eggs for IVF instead.
The discovery is astounding, considering the huge increase of women undergoing IVF when they’re older because they’ve delayed starting a family because of their career.