File photo: Early trials have shown that when such women were given tamoxifen, approximately one in five were able to have a baby using their own eggs. Picture: Reuters

London - A breast cancer wonder drug is being used in IVF to boost success rates for older women.

Tamoxifen is normally given to patients who have undergone surgery for breast cancer to prevent tumours growing back.

But a British clinic is pioneering its use in fertility treatment to help women over 40 who have a limited number of eggs.

Normally older women with a low ovarian reserve have to use donor eggs from someone else, meaning they are not biologically related to the baby.

But early trials have shown that when such women were given tamoxifen, approximately one in five were able to have a baby using their own eggs.

The technique is being tried by Professor Geeta Nargund, medical director of Create Fertility, which has branches across the UK. She carried out a study at a London clinic earlier this year on 31 women with low ovarian reserve whose average age was 40.

They were given daily tamoxifen pills for between five and ten days. The women underwent 54 cycles of IVF between them using fresh and frozen eggs.

The results – first presented at the British Fertility Conference in Edinburgh in January – showed six of the 31 women went on to have babies.

Professor Nargund says her clinic has since used tamoxifen in 100 cycles and the success rate has matched that of the trial.

Tamoxifen has been shown to slash the risk of breast cancer by up to 40 percent.

Researchers believe it works for fertility treatment by lowering oestrogen levels. This triggers the ovaries to produce higher quality eggs, which are more likely to be fertilised into a healthy embryo.

Professor Nargand said: "As the women had more than one embryo transfer, the cumulative birth rate was 19.3 percent per patient using their own eggs.

"But this is an excellent result for women with very low egg reserve because most of them had been told to try donor eggs. The results would be a lot higher in women with normal egg reserve."

Tamoxifen could potentially slash the costs of fertility treatment. In a traditional IVF cycle, a woman would typically inject herself daily for up to four weeks.

She would first use drugs that suppress her own hormones and then use stimulating drugs to produce a large number of eggs.