IVF in young women tied to breast cancer: study

REUTERS - Women who go through in vitro fertilization (IVF) early in life are at a higher risk of developing breast cancer compared to those who dont undergo the treatment, according to an Australian study. But the findings, based on a study of more than 21,000 women and published in the journal Fertility and Sterility, cannot determine whether IVF contributed to the cancers or whether something else could explain the risk.

Roughly 1.7 percent of the 13,644 women who only used fertility drugs without IVF ended up developing breast cancer by the end of the study. That figure was about two percent for women who used fertility drugs and underwent IVF - a difference that researchers said wasnt statistically significant. When they divided the women into different age groups, though, that changed. Women who started taking fertility drugs around their 24th birthday and went through IVF had a 56 percent greater chance of eventually developing breast cancer compared to those in the same age group who only went through fertility 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. 

A possible reason that younger women see an increased risk of breast cancer is that they are exposed to higher levels of circulating estrogen during their cycles of IVF treatment. 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.

Editor: I Googled "IVF and breast cancer" and there were 275 news items about this already within just over 24 hours. Meanwhile, the abortion/breast cancer link gets scant attention. [Corrected comment.]