Doctors can reassure women undergoing fertility treatments that IVF does not increase their risk of ovarian cancer after a large study has found no relationship.
The question of a link has been under dispute for many years and has worried women having assisted conception treatments since the late 70s.
With growing numbers of women having infertility treatments and high incidence of ovarian cancer in Western countries, a team from Denmark have collected results from the largest group of infertile women to date.
54,362 women with infertility problems referred to all Danish fertility clinics between 1963 and 1998 were included in the research. 156 went on to develop ovarian cancer.
Allan Jensen, assistant professor of cancer epidemiology and colleagues at the Danish Cancer Society examined how four groups of fertility drugs (gonadotrophins, clomifene citrate, human chorionic gonadotrophin, and gonadotrophin releasing hormone) administered over an average period of 16 years may have impacted on cancer risk.
They found no overall increased risk for ovarian cancer after use of any fertility drug. They also found no increased risk among women who had undergone 10 or more cycles of treatment or among those who did not become pregnant.
The researchers did however find a 67% increase in risk of serious cancers and use of clomifene. This was found mainly amongst women followed up for 15 years or more after first use of the drug as compared with never use.
But they add: "The risk of serious cancer was not, however, related to the number of cycles using clomifene, and the risk did not differ according to parity." They also speculate that the link might be due to chance.
They conclude their results are "generally reassuring" to women but say they will continue to monitor risk as the majority of women have not reached the age range when ovarian cancer is most likely to develop (early 60s).
"In a society where infertility in women and maternal age at birth of the first child are increasing, the unfavourable effects of fertility drugs (for example, a possible small increase in risk of ovarian cancer) should be balanced against the physical and psychological benefits of a pregnancy made possible only by the use of these drugs," they add.
The article is published on bmj.com