Fertility treatment does not raise overall cancer risk in women

Women who have undergone fertility treatments show a similar incidence of cancer compared to women of the same age, according to a large Australian study.

Researchers from the University of New South Wales (UNSW), Australia, analysed data from nearly 418,000 women who underwent fertility treatment between 1991 and 2018, comparing their cancer rates over a ten-year period to those found in similar aged Australian women from the same areas. The results, published in JAMA Network Open, showed that while small differences emerged in the incidence of certain cancers, the total number of cases was a close match between both groups.

'It is very normal for a specific group of people to have a slightly different cancer profile from the general population', Dr Adrian Walker, joint lead author and research fellow at UNSW Sydney's Centre for Big Data Research in Health, said to FemTech World, 'but as we see here, that doesn't mean that their overall risk is increased.'

The general incidence of invasive cancer in women who had undergone IVF or IUI was comparable to that found in the general population. Women who had been prescribed Clomiphene – a medication used to stimulate ovulation – showed a slight increase, with this difference translating to 8.6 additional cases for every 100,000 women treated per year.

The rate of a few specific cancers was slightly higher among women who had received fertility treatment. This included melanoma, uterine cancer and ovarian cancer (in those who had IVF or IUI with ovarian stimulation), as well as a form of non‑invasive breast cancer (in former IVF patients). The increase represented about three to seven additional cases for every 100,000 women treated per year.

In contrast, certain cancers were slightly less common in women who had received fertility assistance, such as cervical and lung cancers.

The authors stressed that their study cannot demonstrate whether fertility treatments have a causative or protective effect on cancer. As Professor Claire Vajdic, lead researcher at UNSW's Kirby Institute, explained to Femtech World: 'Women who need fertility treatment may differ from other women in ways that affect cancer risk.'

For instance, fertility patients may have pre-existing reproductive conditions, such as endometriosis or polycystic ovary syndrome, which are linked to increased risk of ovarian or uterine cancers. They are also less likely to smoke and more likely to receive cervical screening compared to the general population, which could reduce their risk of developing associated cancers.

These results align with previous findings suggesting that IVF treatment is not linked to increased cancer risks (see BioNews 694, 749, 861 and 1073). As fertility treatment use grows worldwide, researchers emphasise the need for continued monitoring going forward. Future studies will focus on better understanding how underlying infertility, lifestyle factors and treatment exposures interact, helping to refine risk counselling and ensure women receive clear, evidence‑based guidance when considering fertility treatment.