Birth Control & Cancer: Which Methods Raise, Lower Risk

If you're a woman of childbearing years who wants to delay pregnancy, you might have heard that some birth control methods are linked to cancer. Spend a minute online and you'll probably find more than a handful of contradicting reports saying some types cause cancer, while others fend it off. How do you know what to believe?

"This is a perplexing issue for many women," says Mia Gaudet, Strategic Director of Breast and Gynecologic Cancer Research at the American Cancer Society. For example, "there is consistent evidence that oral contraceptives (birth control pills) increase a woman's risk of breast and cervical cancer but decrease the risk of endometrial and ovarian cancer."

Here is a quick look at some popular birth control options and what we know today about their links to common cancers.

Increased Risk: Breast Cancer

If you take or have taken birth control pills in the recent past, you are slightly more likely to develop breast cancer than women who've never used them. Researchers aren't sure if the link is due to the estrogen or progesterone. Some research hints it might be caused by high-dose estrogen, but women in studies who took the progesterone-only shot Depo-Provera have also been found to have higher rates of breast cancer.

"It is just not really clear," says Gaudet. "But interestingly, the increased risk goes away after you've been off the oral contraceptive for 10 or more years."

Things that might lower your risk:

• Reducing the number of years you are taking birth control pills.
• Choosing a different form of contraception. For example, a non-hormonal intrauterine device (IUD) is a reversible form of birth control that is not linked to breast cancer. Bonus: It might also lower your risk of cervical and endometrial cancer.

Increased Risk: Cervical Cancer

Taking birth control pills for 5 or more years might make you more likely to get cervical cancer. The longer you use them, the higher your risk. The risk tends to go back down over time when you stop taking the pills.

However, most cervical cancers are caused by a persistent infection with the human papilloma virus (HPV). Today, doctors typically screen for such infections during a woman's health exam and Pap smear. "If you receive regular check-ups and HPV screening, this cancer should be less of a concern," says Gaudet.

Things that might lower your risk:

• Getting regular HPV screenings.
• Choosing another form of birth control, like an IUD.

Reduced Risk: Endometrial Cancer

Birth control pills containing both estrogen and progesterone can lower your risk of this type of cancer. The longer you take them, the lower your risk. The benefit seems to last for at least a decade after you stop.

An IUD might also help lower your risk of endometrial cancer.

Reduced Risk: Ovarian Cancer

Combo estrogen/progesterone birth control pills can lower your risk of this type of cancer. The benefit starts within 3 to 6 months after starting the pill. The longer you take it, the lower your risk. Depo-Provera also lowers the risk, especially if you use it for more than 3 years.

Don't want to take the pill? "Women who are finished with reproduction might choose to have their tubes removed or have tubal ligation, which also help reduce the risk of ovarian cancer," says Gaudet.

Reduced Risk: Colon Cancer

The protective benefits of birth control pills might not be limited to certain reproductive cancers. Growing evidence says the pill may lower your risk of developing colorectal cancer while you take it. More research is needed.

The Bottom Line

When choosing a form of birth control, talk to your doctor about all of your options. There are many factors to consider. Cancer risk is only one of them. Birth control can have many health effects; some may be bad while others may be good – like more regular menstrual cycles. Know that oral contraceptives play an important role not only in family planning but also managing other health problems like endometriosis," says Gaudet. "It's also important for a woman to consider her own family history and spectrum of cancers in her family."