Birth Control Pills and Cancer
Donald Aulds, M.D.
Every week, patients express concern about the risk of developing cancer if they are presently, or have previously been on birth control pills. Birth control pills were first introduced to the United States in the early 1960s. Since then the pill has become the most popular form of birth control in this country. Slowly questions have begun to surface about side effects and long-term effects. Adequate time has passed since the introduction of the pill for researchers to perform studies to support the following information.
What has raised the concern about the risk of cancer with use of birth control pills?
Medical research suggests that some types of cancer depend on hormones for their development and growth. Because of this research data, researchers have focused attention on birth control pills over the past 40 years. Estrogen stimulates growth and development of the endometrium during the first half of the menstrual cycle and influences breast tissue throughout life. Progesterone prepares the endometrium during the second half of the cycle to accept an egg if pregnancy occurs. Because of this, progesterone in birth control pills suppresses ovulation. The synthetic or man-made progesterone used in birth control pills are called progestins.
How do birth control pills affect breast cancer risk?
The risk of developing breast cancer depends on several factors, including female hormones. Hormonal factors that have been shown to increase the risk of breast cancer include early start of menstrual period (before age 12), hormonal fluctuations during menopause, and not having been pregnant. Early studies suggested a very slight increase in breast cancer for women using birth control pills. The findings of the Women's Contraceptive and Reproductive Experiences Study showed that current or former use of birth control pills did not significantly increase the risk of breast cancer. There was no significant difference in incidence regardless of race, age, or family history of breast cancer.
Is there a relationship of birth control pills and endometrial or ovarian cancer?
In numerous studies, birth control pills have been shown to reduce the risk of ovarian cancer. Research from Harvard University reported an analysis of 20 different studies, which showed that the risk of ovarian cancer decreased with increasing length of use of the pill. After one year of use, the risk of ovarian cancer was reported to have decreased by as much as 10 to 12 percent. Studies have shown that the type of hormones or the strength of hormones does not change the results of the studies.
Birth control pills have also been shown to reduce the risk of endometrial cancer. Again, the risk of endometrial cancer decreased with increasing length of use of the pill. This effect has bee shown to continue for many years after use of the pill is discontinued.
Ovarian and endometrial cancer are decreased due to the pill blocking ovulation and replacing and stabilizing the hormone levels in the body. During the monthly cycle, hormone levels fluctuate from high to low levels in order to control the pattern of the menstrual flow. With birth control pills, the hormone levels are more consistent, which decreases stimulation to the ovarian and endometrial tissues. Birth control pills also have a tendency to decrease the build up of the endometrium, so there is a decreased risk of abnormal cell growth.
If you have concerns about your risk of cancer with the birth control pill, you should talk to your doctor and get your questions answered. If you are on birth control pills, as with all prescription medications, it is important that you are aware of any associated risks and complications.
More about Dr. Aulds
Donald G. Aulds, MD is an Obstetrician and Gynecologist and currently serves as the Medical Director for both the Women's Center and the Best Start Program of North Alabama. He is a Diplomat of the American Board of Obstetrics and Gynecology and Fellow of the American College of Obstetricians and Gynecologists.
Dr. Aulds completed his medical education at Louisiana State University School of Medicine, New Orleans, LA and his Internship and Residency in Obstetrics and Gynecology at Ochsner Medical Foundation, New Orleans, LA.
Dr. Aulds has been an active member of the Huntsville Hospital Medical Staff since 1980.
