Abortion Unlikely to Raise Risk of Breast Cancer, Danish Study Finds

A large study has concluded that an abortion is unlikely to raise a woman’s risk of breast cancer, as many have feared.

The new research, conducted in Denmark, is by far the biggest and most sophisticated examination yet of this contentious issue.

Earlier studies have conflicted, but taken together, they suggest that abortion raises a woman’s breast cancer risk by about 30%. However, those studies have been criticized because they depend on women speaking honestly about whether they have had abortions.

Some researchers believe that cancer victims are more likely than healthy women to acknowledge having had an abortion because they have already disclosed other intimate medical details to their doctors. That would tend to make the risk of breast cancer after an abortion look higher.

The new Danish study gets around the issue of lying by relying solely on medical records. Everyone in Denmark gets an identification number and their medical histories may be tracked.

The results, published in Thursday’s New England Journal of Medicine, were based on a review of all the cases of breast cancer and abortion in Denmark among the 1.5 million women born between 1935 and 1978.