A recent study suggests that women who take birth control pills may be increasing their risk of developing breast cancer. The study, which was conducted at the Fred Hutchinson Cancer Research Center in Seattle and published in the journal Cancer Research, found that oral contraceptive users were 50% more likely to be diagnosed with the disease compared to women who did not take birth control pills. Each year, approximately 40,000 women die from breast cancer in the United States.
What Kind of Oral Contraceptives Increase the Risk of Breast Cancer?
According to the study, the breast cancer risk varied depending on the type of birth control pill the women took:
- The use of high-dose estrogen birth control pills was associated with a 2.7-fold increase in breast cancer risk;
- Moderate-dose estrogen contraceptives were linked to a 1.6-fold increase;
- Pills which contained ethynodiol diacetate (which are sold as Continuin or Femulen) were related to a 2.6-fold higher risk;
- Triphasic combination pills containing approximately 0.75 mgs of norethindrone each (sold as Ortho 75) increased the risk of breast cancer 3.1-fold, and
- No increased risk was found with low-dose estrogen birth control pills.
“Our results suggest that 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, author of the study. Beaber went on to state that previous studies have suggested that the breast cancer risk decreases sharply after women stop taking oral contraceptives.
For the study, researchers looked at health records and birth control pill use in 1,102 women between the ages of 20 and 49 who had been diagnosed with breast cancer, and 21,952 women in the same age range who did not have the disease. Unlike earlier studies that relied on data which depended on women’s self-report or recall, the new research was based on electronic pharmacy records that included the medication name, dosage and duration of use.
How Can Birth Control Pills Cause Cancer?
Estrogen signals the breasts to stimulate the growth of epithelial cells. When there’s too much estrogen, the body is giving an unusually high signal. Normally, estrogen makes women’s breast proliferate and grow larger. However, multiple proliferations could allow this growth to continue in an unregulated way, which could ultimately result in a cancerous tumor. The results of the study are consistent with previous research which has found that the breast cancer risk increases with some birth control pills, though other studies have not identified this link.
Breast Cancer Symptoms
Change in how the breast or nipple feels:
- Nipple tenderness or a lump in or near the breast
- Change in the skin texture or an enlargement of pores in the skin of the breast
- A lump in the breast
Change in the breast or nipple appearance:
- Any unexplained change in the size or shape of the breast
- Dimpling on the breast
- Unexplained swelling/shrinkage of the breast (especially if on one side only)
- Recent asymmetry of the breasts
- Nipple that is turned slightly inward or inverted
- Skin of the breast, areola, or nipple that becomes scaly, red, or swollen
- Milky, bloody or clear discharge that is present when a woman is not breastfeeding should be checked by her doctor, although this is not always a symptom of breast cancer.
A risk factor is anything that increases the likelihood that you will develop breast cancer. Many risk factors for breast cancer are beyond a woman’s control such as age, family history and medical history. However, there are a number of major risk factors that you can control including:
- Having children – Women who have had no children or who had their first child after the age of 30 have an increased risk of breast cancer.
- Birth control pills – Women who take oral contraceptives may be at an increased risk of developing breast cancer compared to women who use other forms of birth control.
- Hormone therapy – Has been used for decades to treat the symptoms of menopause and to help prevent osteoporosis. Earlier research suggested it may have other health benefits as well, but these benefits have not been found in more recent studies.
- Breastfeeding – Some studies have found that breastfeeding may lower the cancer risk slightly, especially if it is continued for up to 2 years. However, this has been a difficult area to study, particularly in countries like the U.S., where breastfeeding for this long is uncommon.
- Alcohol – The use of alcohol has been well documented as a risk factor for breast cancer. This risk increases with the amount of alcohol consumed: compared with non-drinkers, women who consume one alcoholic beverage per day have a slight increased risk. Women who consume two to five drinks daily have about 1½ times the risk of women who don’t drink alcohol.
Birth Control Pill Side Effects
In addition to having the potential to cause breast cancer, birth control pills have been linked to the following serious side effects:
- High blood pressure
- Blood clots
- Heart attack
- Liver tumors
Other, more moderate birth control pill side effects may include:
- Breakthrough bleeding or spotting
- Breast soreness
- Decreased libido
- Weight gain