Cancer & Birth Control

Cancer & birth control at a glance

• Taking birth control pills (oral contraceptives) has been shown to increase the risks of breast cancer and cervical cancer, and may increase the risk of liver cancer.
• Taking birth control pills reduces the risk of ovarian and uterine cancers.
• The primary female sex hormones, estrogen and progesterone, have been shown to affect the development and growth of some cancer cells; these hormones are present in some birth control pills and in other hormone-based patches, implants, injections and rings.
• The evidence of a link between birth control pills and breast cancer isn’t clear and seems to be related to several factors, including family genetics, age and the type of birth control pills taken.

Breast cancer risk & birth control

Many studies have been conducted on a link between birth control pills and breast cancer with mixed results. The National Cancer Institute says that an evaluation of multiple studies found that taking birth control pills results in a slightly higher risk of breast cancer than not taking birth control pills. The highest risk was found among women who started taking birth control pills as teenagers. Ten years after stopping birth control pills, women show no increase in breast cancer risk.

More studies are needed before a definitive relationship can be established between birth control pills and breast cancer.

The link between birth control pills and breast cancer centers on the fact that birth control pills contain the female hormones that, when occurring naturally in elevated levels, increase a woman’s risk of getting breast cancer. Some of these risk factors that cause a natural increase in hormone exposure include:

• Starting menstruation at an early age
• Having a child at a later age
• Not having a child
• Experiencing menopause at a later age

Women with a family history of breast cancer should discuss the possible increase of their risk of breast cancer by taking birth control pills.

Some studies indicate that women age 45 and over who take birth control pills have a greater risk of getting breast cancer. This could be because earlier versions of birth control pills, known as a “combined oral contraceptive,” contained higher doses of the estrogen and progesterone hormones. Although combination birth control pills are still in use today by many women, the hormone dosages are lower.

A newer form of birth control pill, called the “mini pill,” contains lower doses of a man-made substitute for progesterone called progestin, which may be a better form of birth control for women already at risk for breast cancer. 

Cervical cancer risk & birth control pills

Use of birth control pills for longer than five years is linked to an increased risk in cervical cancer; and the longer the use, the higher the risk. However, after women stop taking birth control pills the risk of cervical cancer declines over time.

Most cervical cancers are caused by infection with tumor-forming or high-risk types of the human papillomavirus (HPV). A World Health Organization analysis found that women infected with HPV who took birth control pills were almost three times more at risk of getting cervical cancer.

It is thought that the hormones in birth control pills may make the cervical cells more susceptible to HPV infection or enable the HPV to progress to cervical cancer, although the connection is not clear.

Liver cancer & birth control pills

Taking birth control pills is associated with an increase in benign liver tumors. These tumors rarely become malignant (cancerous).

Some research has suggested that women who take birth control for more than five years are at a higher risk of developing malignant tumors, also called hepatocellular carcinoma. However, this research considered the older form of birth control pills with higher doses of hormones. More research must be conducted before a link between birth control and liver cancer can be proved or refuted.

Ovarian cancer risk & birth control pills

Many studies have shown a direct correlation between the use of birth control pills and a reduction in the risk of ovarian cancer. The reduction increases with the duration of time that birth control pills are taken.

An analysis of several studies shows that a woman who has taken birth control pills for one year decreases her risk of ovarian cancer by 10 to 12 percent, and after being on the pill for five years the risk for ovarian cancer is cut in half.

Studies to determine whether the positive effects are related to the type of birth control pill taken (the older combination form or the newer low-dose form) have mixed results, but both appear to be beneficial in reducing ovarian cancer risk.

Uterine cancer risk & birth control pills

Using birth control pills reduces the risk of uterine cancer, also known as endometrial cancer. The lowered risk is greatest among women who have been on the pill longer. This reduced risk of uterine cancer extends for at least 10 years after a woman stops taking birth control pills.

Should I use birth control pills if I have cancer?

Women who have had or currently have breast cancer should not take birth control pills. Women who have uterine cancer also should not take birth control pills. The hormones in birth control pills have a negative effect on some cancer tumors. It is best for women with any form of cancer to consult their physician about taking birth control pills.

Women who are receiving chemotherapy treatment for cancer do not want to get pregnant, as chemotherapy drugs can harm a developing baby. They should consult their physician to see if they can take birth control pills or discuss what method of birth control would be most effective.

Should I use other estrogen-based birth control devices if I have breast cancer?

Not without consulting your physician. Birth control implants, patches, injections and vaginal rings that deliver estrogen to prevent conception may not be safe for a woman who has or has had breast cancer. Your physician will know whether these types of birth control are right for you.