Researchers at the Danish Cancer Society have ascertained that taking fertility drugs does not increase a woman's chance of developing ovarian cancer. The results of the study are published in the British Medical Journal.

Allan Jensen and colleagues studied 54,362 women referred to fertility clinics between 1963 and 1998, and determined that none of the four groups of fertility drugs monitored as part of the research project contributed to ovarian cancer. Of all the women followed, 156 went on to develop ovarian cancer. However, as many of the women have not yet reached the age where ovarian cancer is most common, researchers will continue to monitor them going forward.

Previous studies have yielded conflicting results about whether fertility drugs increase the risk of ovarian cancer in the case of women who undergo several cycles of IVF, but the study found that there was no increased risk among women who underwent 10 or more cycles of IVF or those who did not become pregnant. There was increased incidence of ovarian cancer among women who had taken the drug clomiphene, but researchers determined that this was a coincidental association.

Allan Jensen, assistant professor of cancer epidemiology at the Danish Cancer Society, commented that, 'you should always balance a possible small increase in ovarian cancer risk with the physical and psychological benefits of pregnancy made possible only by use of these drugs'. Complicating the research is the fact that infertile women appear to be at a higher risk of developing ovarian cancer aside from undergoing fertility treatment.

Ovarian cancer is also rare, and so the research benefited by using a large study population. Professor Hani Gabra, Director of the Ovarian Cancer Action Research Centre at Imperial College London, commented that, 'this large-scale study supports previous research that found that overall there is no increased risk of developing ovarian cancer amongst women receiving fertility treatment. The researchers point out that longer follow up is required for a more definitive answer. This will be a huge relief to many women who have undergone fertility treatment'. Dr Allen Pacey, Secretary of the British Fertility Society, commented that the study was 'reassuring' and stated, 'there are a few caveats, but this should put most people's minds at rest'.

In the UK 6,800 women are diagnosed with ovarian cancer annually, and the disease results in 4,400 deaths per year. The disease is difficult to detect in the early stages when it is most treatable, and it has a poor survival rate, with only 30 per cent of women living five years after diagnosis.