IVF treatment early in adulthood dramatically increases a woman’s chance of developing breast cancer, research at University of Western Australia suggests.
Women who started taking fertility drugs and went through IVF around their 24th birthday were found to have a 56 per cent greater chance of developing breast cancer than those in the same age group who went through treatments without IVF.
But there was no increased risk for women who started fertility treatments when they were about 40 years old, regardless of whether they had IVF or not, according to the Australian study
The researchers said: ‘For younger women there is some cause for concern, because it appears that they may face an increased risk of breast cancer after IVF treatment.’
The findings were based on a study of more than 21,000 women and published in the journal Fertility and Sterility.
Study author Louise Stewart from the University of Western Australia said younger women might see an increased risk of breast cancer because they are exposed to higher levels of circulating estrogen during their cycles of IVF treatment.
However, Stewart said they couldn’t yet say that IVF was causing the increased cancer risk in younger women, as these women could be different in some significant way from those who only have other types of fertility treatment.
‘If for example, younger women who had IVF were more likely to have a specific cause of infertility, and this was related to an increased risk of breast cancer, then it would appear that IVF was related to breast cancer when in fact it was the type of infertility that was more common in women who had IVF,’ she said.
Linda Giudice, president-elect of the American Society of Reproductive Medicine, added: ‘The development of breast cancer is linked to estrogen exposure and the longer one is exposed, the greater the risk.
‘In an IVF cycle there is a short, but significant elevation in circulating estrogen, and whether this is linked to the observations found in the study is not clear at this time.’
The researchers said the study results would reassure women who start IVF treatment in their 30s and 40s.
However, they added: ‘Women should be aware that delivering their first child late in reproductive life, whether assisted by IVF or not, is associated with an increased risk of breast cancer.’
Statistically, younger women have a greater chance of successfully having a baby following IVF.
They suggested a follow-up study of women who undergo a greater range of cycles to see if there’s a connection between IVF ‘dose’ and breast cancer rate.