High doses of IVF drugs may cause harm to eggs

High doses of drugs used to stimulate the ovaries of older women undergoing fertility treatment may be causing chromosomal abnormalities in their eggs, leading to failed pregnancies and even, potentially, babies with conditions such as Down's syndrome. Hormonal drugs are used in IVF to encourage the ovaries to produce extra eggs, increasing the chances that some will be successfully fertilised and implanted in the womb. One of the biggest hazards of IVF is overstimulation, which can make a woman very ill. Under the age of 35, mild stimulation is used. But over 35, when the ovaries are naturally producing fewer eggs, larger doses of hormones have conventionally been used. Research led by a UK team, presented at the annual European Society of Human Reproduction and Embryology (ESHRE) conference in Stockholm, has now shown that the resultant eggs have a higher proportion of chromosomal abnormalities than would be expected in untreated women of the same age group. Embryos created from eggs with chromosomal abnormalities do not usually proceed to a successful pregnancy and live birth. They may not implant in the...