A large Australian study has found that women who undergo medically assisted reproduction (MAR) do not appear to have a higher overall risk of cancer compared with the general population.
The population-based cohort study, published in JAMA Network Open, analysed cancer incidence among nearly 418,000 Australian women who received fertility treatment between 1991 and 2018.
Using linked national administrative and registry datasets, researchers compared cancer incidence in women exposed to MAR—including assisted reproductive technology (ART), intrauterine insemination with ovarian stimulation (IUI/OS), and ovulation induction with clomiphene citrate—with that of the age-, jurisdiction-, and calendar year–matched general population. Some women were exposed to more than one treatment type during the study period.
CLINICAL SUMMARY
What was examined
A population-based Australian cohort study compared cancer incidence in 417,984 women who underwent medically assisted reproduction between 1991 and 2018 with that of the age-matched general population.
Key findings
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Overall cancer incidence among women exposed to medically assisted reproduction was similar to that of the general population.
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Higher incidence was observed for some cancers, including uterine cancer, ovarian cancer after ART or IUI/OS, melanoma, and in situ breast cancer after ART.
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The incidence of cervical cancer and lung cancer was lower in women who had received fertility treatment.
Clinical implications
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Fertility treatment does not appear to increase overall cancer risk at a population level.
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Small increases in some hormone-related cancers may reflect underlying infertility, surveillance effects, or lifestyle factors rather than treatment itself.
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The findings may help inform counselling and follow-up care for women undergoing medically assisted reproduction.
Across all treatment groups, overall invasive cancer incidence was similar to that of the general population. Standardised incidence ratios were 1.00 for women who had used ART and 0.99 for those who had undergone IUI with ovarian stimulation. Cancer incidence was slightly higher among women who had used clomiphene citrate (SIR 1.04), although the absolute increase was small.
Some individual cancers occurred more frequently in women who had received fertility treatment. Uterine cancer incidence was higher across all MAR groups, with standardised incidence ratios ranging from 1.23 to 1.83. Ovarian cancer incidence was also elevated among women who had undergone ART (SIR 1.23) or IUI with ovarian stimulation (SIR 1.18), and melanoma incidence was modestly increased across all cohorts.
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In situ breast cancer was more common among women who had received ART, although the incidence of invasive breast cancer was similar to that of the general population.
Conversely, several cancers were less common among women exposed to MAR, including cervical cancer and cancers of the trachea, bronchus, and lung.
Despite these differences for specific cancer types, the absolute excess risk was small. For cancers with increased incidence, the additional number of cases ranged from fewer than one to around six extra cases per 100,000 person-years.
The authors note that observed differences may reflect underlying infertility-related factors, lifestyle characteristics, or increased medical surveillance rather than a direct effect of fertility treatment itself.
They conclude that the findings may help reassure women considering or undergoing fertility treatment, while also highlighting the importance of ongoing attention to modifiable cancer risk factors and routine preventive care.
Paper: Vajdic, C M., et al. Cancer Incidence in Women After Medically Assisted Reproduction. JAMA Network Open. 2026;9(3):e261332.doi:10.1001/jamanetworkopen.2026.1332 Access online here.
