Birth Control Pill and Breast Cancer Risk

Since the early 1960s, birth control pills have become the most popular and one of the most effective forms of birth control used in the U.S. But an association between estrogen and an increased risk of breast cancer has led to a continuing debate about the role birth control pills may play in developing breast cancer.

For most women, especially young women, experts say the benefits of birth control pills far outweigh the risk. But here are some frequently asked questions and answers about the controversy.

Does Taking Birth Control Pills Increase My Risk of Developing Breast Cancer?

Maybe. Studies that have examined the use of oral contraceptives as a risk factor for breast cancer have produced conflicting results. Some researchers think this might be due to the fact that the level of hormones in birth control pills has changed since they were first studied. Early birth control pills contained much higher levels of hormones than today's low-dose pills and posed a higher risk.

Scandinavian researchers have noted an increase in breast cancer in a group of women that were currently taking or had recently taken birth control pills. Longer use of the pill seemed to increase the risk. Similar research found that 10 years or more after women stopped using birth control pills, their breast cancer risk returned to the same level as if they had never used birth control pills.

However, another reputable study by Women's Contraceptive and Reproductive Experience (Women's CARE) done between 1994 and 1998 showed there was no increased risk of breast cancer in current or former users of birth control pills.

In general, most studies have not found an overall increased risk of breast cancer due to the use of oral contraceptives.

My Family Has a History of Breast Cancer. Should I Take Birth Control Pills?

Those with a family history of breast cancer related to mutations in the BRCA genes should use caution before taking birth control pills. Families at increased risk of breast cancer who are carriers of alterations in these genes may further increase their risk of breast cancer by taking birth control pills. Recent studies show taking birth control pills did not increase the risk in women who are carriers of the abnormal form of the BRCA2 gene, but did in those with the altered BRCA1 gene.

Women should discuss their family history of cancer with their doctor when evaluating the risks and benefits of using birth control pills.

Does the Risk of Breast Cancer Associated With Birth Control Pills Vary by Age?

Yes, according to the latest research. A study of more than 100,000 women suggests that the increased breast cancer risk associated with birth control pills is highest among older women. The study found that the risk of breast cancer was greatest among women aged 45 and over who were still using the pill. This group of women was nearly one-and-a-half times as likely to get breast cancer as women who had never used the pill.

But experts caution that many of the women were using older birth control pills that contained higher doses of hormones. Today's lower-dose birth control pills are thought to reduce this risk.

Do Birth Control Pills Reduce the Risk of Any Other Cancers?

Yes. The pill's protective effect against ovarian cancer has been well documented. Ovarian cancer risk is reduced by as much as 30%-50% among women taking birth control pills for at least three years. New studies show that as little as six months of use can dramatically reduce the risk of ovarian cancer, and that protective effect increases the longer a woman is on the pill.

There was also a reduced incidence of endometrial cancer.

And a new study suggests oral contraceptives may also reduce the risk of colorectal cancers. The European study found that women who had ever used birth control pills were about 20% less likely to develop colorectal cancers than women who had never used the pills. The reduced risk was great even if the woman had used the pills recently.

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