IVF at Young Age May Raise Breast Cancer Risk
Researchers Find Increased Risk for Breast Cancer When IVF Started at Age 24
Although the study results should be "reassuring" to women who begin IVF treatment in their 30s and 40s, "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," the researchers write.
The study also found that delivery of twins or other multiples was associated with a reduced breast cancer risk, which has also been observed in some previous studies.
The study "provides another piece in the puzzle of risk factors and the likelihood of getting it [breast cancer] or not getting it," says Barbara Collura, MA, executive director of RESOLVE: The National Infertility Organization. "Is it going to make women think differently about IVF or not? I don't think so."
Breast cancer is perhaps the furthest thing from women's minds when their doctor suggests IVF, Collura says. "Your thought is, 'will this get me pregnant'" she says, followed by concerns about paying for it.
Sometimes a possible connection between the drugs used in IVF treatment and breast cancer does come up in hindsight, though, especially in women over 35 who've had more than three cycles, Collura says. "It's this after-the-fact kind of question people have, and they want some data."
Stewart's study doesn't have an answer for those women, however. Half of the women in her study underwent only one or two cycles of IVF, and information about the types or doses of fertility drugs they received weren't available. The researchers suggest 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.
Stewart's study appears online in the journal Fertility and Sterility.