A new study in the British Medical Journal has found no evidence that the drugs used in infertility treatment increase women's risk of ovarian cancer.
Researchers at the Danish Cancer Society analysed data on 54,362 women who had undergone infertility treatment between 1963 and 1998.
They found no evidence to suggest that fertility drugs increase the risk of ovarian cancer, even if used during multiple cycles of IVF.
They concluded: "The results of our large nationwide study, which represents the largest number of cases of ovarian cancer in any cohort of women with infertility problems to date, generally concur with those of most previous epidemiological studies."
The researchers added that the results provide "reassuring evidence for the absence of a strong association between use of fertility drugs and risk of ovarian cancer".
Liz Baker, Cancer Research UK's senior science information officer, said that the study reinforces the findings of previous research.
She noted that the biggest influence on the risk of ovarian cancer is a woman's increasing age.