Some Birth Control Pills with High-Dose Estrogen May Increase Breast Cancer Risk

It turns out that some birth control pills could increase a woman's risk of breast cancer. Scientists have found that pills containing high-dose estrogen and a few other formulations could contribute to a woman's likelihood of developing the disease.

In order to study the impacts of birth control pills on women, the researchers examined 1,102 women diagnosed with breast cancer and 21,952 controls. The scientists used electronic pharmacy records to gather detailed information on contraceptive use, including drug name. In the end, they found that recent oral contraceptive use actually increased breast cancer risk by 50 percent, compared with never or former use.

"Our results suggest that the use of contemporary oral contraceptives [birth control pills] in the past year is associated with an increased breast cancer risk relative to never or former oral contraceptive use, and that this risk may vary by oral contraceptive formulation," said Elisabeth F. Beaber, one of the researchers, in a news release.

In fact, the researchers found that birth control pills containing high-dose estrogen increased breast cancer risk 2.7-fold. Those containing moderate-dose estrogen increased the risk about 1.6-fold. Contraceptives containing ethynodiol diacetate increased the risk 2.6-fold, and tirphasic combination pills containing an average of .75 milligrams of norethindrone increased the risk 3.1-fold.

That said, the researchers caution that more research needs to be conducted before any firm conclusions are drawn.

"Our results require confirmation and should be interpreted cautious," said Beaber. "Breast cancer is rare among young women and there are numerous established health benefits associated with oral contraceptive use that must be considered. In addition, prior studies suggest that the increased risk associated with recent oral contraceptive use declines after stopping oral contraceptives."

The findings reveal that more research should be conducted in order to find out how oral contraceptives may impact women. This way, scientists can determine whether the benefits outweigh the drawbacks.

The findings are published in the journal Cancer Research.