Oestrogen receptor link to infertility

Some women may not respond to fertility drugs if they lack a certain oestrogen-related gene, according to a new study on mice. Scientists at the National Institute of Environmental Health Sciences (NIEHS) in the US found that mice engineered to lack the gene for oestrogen receptor beta did not ovulate in response to fertility drugs.

'We found that the beta oestrogen receptor plays a role in moving the egg outside the ovary so it can be fertilised', said Kenneth Korach of the NIEHS. If the same is true in humans, it could help explain some cases of infertility and also help women to choose the most effective treatments. The NIEHS is hopeful that the results could lead to a simple blood test that would be able to provide enough information to determine if a genetic mutation may be altering the function of oestrogen receptor beta. The blood test, coupled with information from other medical tests and evaluations by physicians will help diagnose infertility and better determine treatment options.

The researchers treated normal and genetically engineered female mice with fertility drugs similar to those used by women undergoing fertility treatments. The mice bred to lack the receptor gene were more likely to be infertile, or had fewer offspring. When treated with fertility drugs, they did not produce more eggs.

The NIEHS may also investigate whether defects in oestrogen receptor beta are inherited, or caused by environmental effects - and whether diet can change the effects. Genisten, a compound found in soy products, can mimic the effects of oestrogen and could possibly interact with the receptor and alter ovarian function.

'Dealing with infertility can be emotionally, financially and physically draining', said Dr David Schwartz, director of the NIEHS. 'If we can help couples understand the reasons for their infertility, doctors can further define their treatment options, help them to minimise the expense and risk of taking drugs that may be less effective for them, and increase their chances of having a healthy child'.