Can IVF Cause Cancer?

Today’s post addresses a question that I am often asked at the clinic – Can IVF cause cancer?

This concern very likely stems from a study done 12 years ago, which has since been well-publicised. It reported that the use of Clomid, which is a fertility medication widely used to treat ovulatory dysfunction in women, might increase the risk of breast and uterine cancer.

Understandably, this has caused some infertility patients to wonder if the treatments they will undergo are safe. Therefore, today I’d like to reassure you by providing references to other studies on the subject.

It’s important to note that since that study was first published, more studies have been conducted and most have found no significant link between Clomid use and cancer risk. One such study, which in fact offers the strongest evidence that Clomid and other ovarian-stimulating drugs do not increase the risk of ovarian cancer, comes from the Cochrane Review.

Published in 2013, the review looked at studies from 1990 to February 2013 that involved 182,972 women. The review not only found no evidence of increased ovarian cancer in women who use any fertility drug, but also pointed out that studies claiming there is an increased cancer risk were unreliable. This is because their sample sizes were too small for drawing conclusions and they did not take into consideration other potential risks for cancer.

For example, if a woman has never experienced pregnancy, her risk of cancer increases. Certain causes of infertility can also cause an increased risk of cancer, for example obesity, PCOS and endometriosis. So in fact, the increased risk of cancer noted in those studies may not be related to the medications at all.

In fact, ironically, some studies showed a decreased risk of developing breast and uterine cancer among infertile women on Clomid, in comparison to infertile women who did not seek treatment for infertility.

There are two other studies, with substantial sample sizes, which included 25,108 women from the Netherlands who received IVF treatment between 1980 and 1995, found that there was no increased risk of breast cancer. Another study, by the Institute of Child Health at University College London, which involved over 250,000 British women undergoing IVF between 1991 and 2010, also found no increased risk of breast or uterine cancer in those patients. However, they learned that IVF patients had a slightly higher risk of ovarian cancer – 15 in 10,000 odds, as compared to women who had never undergone IVF, who had 11 in 10,000 odds.

So as a consensus, from the studies quoted above and others like them, you can rest assured that fertility drugs like Clomid do not increase your risk of developing breast or uterine cancer. However, because infertility itself is a cancer risk factor, it is best that you undergo the necessary follow-up after your infertility diagnosis.

Should you have any concerns on the medications and treatments for infertility, please don’t hesitate to speak to your infertility consultant.