The need for safe, effective birth control is shared by many women around the world. More than 10 million American women use birth control pills — and many use this method of contraception for long periods of time. If you’re one of them, you know why: the tiny pills are easy to take and extremely effective if you take them as directed. Plus, they help some women deal with other challenging issues such as acne, PMS, heavy periods, and mood swings.
Easy, effective birth control is important for many women. But it’s also important that birth control be safe. There are concerns that birth control pills and other contraceptives that use hormones to block pregnancy may overstimulate breast cells, which can increase the risk of breast cancer.
The concern is greater if you’re at high risk for the disease because of:
- strong family history of the disease
- past breast biopsies showing abnormal cells
- you or someone in your family has an abnormal breast cancer gene
If you’ve already been diagnosed with breast cancer, you shouldn’t use contraceptives that use hormones. That’s because there’s evidence that these medicines might increase the risk of the cancer coming back (recurrence).
Doctors have debated about the seriousness of these breast cancer-related concerns for decades. Still, many people believe we don’t completely understand how hormonal contraceptives affect our bodies, so we need to be careful. If you’re someone who uses birth control pills or are thinking about using them in the future, it’s important to have the most up-to-date information so you can make the best decisions for YOU.
How does hormonal birth control work?
“Hormonal contraceptive” is any type of birth control that contains man-made versions of the female hormones estrogen and progesterone (called progestin), or progestin only. The most popular form of hormonal contraceptive is the pill, but hormonal birth control also comes in the form of a patch, an injection, an under-the-skin implant, an intrauterine device, and a ring that fits inside the vagina.
The dose of hormones is different in each form of hormonal birth control. Different brands of pills also have different doses. Some pills provide a steady dose of hormones throughout the month while others offer doses that vary by week. Some pills give you an overall smaller dose of hormones than others. Still, all of today’s hormonal contraceptives use much smaller doses of hormones than earlier versions of birth control pills. The original pills released in the 1960s contained up to 5 times more estrogen and up to 10 times more progestin compared to current versions.
Hormonal contraceptives work by taking control of your menstrual cycle. Their man-made hormones overpower your body’s own natural estrogen and progestin hormones that control your periods. Hormonal contraceptives prevent pregnancy in a combination of ways:
- by preventing the release of eggs from the ovaries (ovulation)
- by changing the lining of the uterus so the egg can’t develop
- by thickening cervical mucus, which blocks sperm from entering the uterus
Do hormonal contraceptives cause cancer?
We know that estrogen and progestin can affect the development and growth of some cancers. Since hormonal contraceptives increase blood levels of these hormones, researchers have looked for possible links between hormonal contraceptive use and cancer risk.
All of the big studies on any possible link track large numbers of women using hormonal contraception and compare them to women using other forms of contraception. It’s nearly impossible to do a controlled study randomizing women to different types of contraception such as an IUD versus hormonal contraceptives versus a diaphragm. That’s because there are medical reasons, strong personal preferences, insurance coverage issues, religious considerations, and other reasons that influence which method a particular woman chooses. Plus researchers could NEVER do a study that compares birth control pills to a placebo (sugar pill) because it could result in unwanted pregnancies.
Here’s what we do know: it appears that hormonal birth control has both risks and benefits when it comes to cancer.
- Hormonal birth control slightly reduces the risk of uterine and ovarian cancer. This is probably because ovarian function is mostly shut down in women who take the pill. When the ovaries stop releasing eggs and making the usual supply of hormones, the ovaries are less likely to develop cancer. Also, the uterine lining is less likely to develop cancer when hormone levels are low. You only have to take hormonal contraception for 5 years to be protected against ovarian cancer (you can take the pills for 5 years straight or for periods that add up to 5 years).
- Hormonal birth control is associated with an increased risk of cervical cancer. The link between using hormonal birth control and cervical cancer is probably just coincidental. That’s because women who are sexually active — which includes most women on hormonal birth control — have a higher risk of becoming infected with human papilloma virus. The human papilloma virus is an infection that causes almost all cervical cancers. (There is a vaccine that helps protect women and girls against some of the most common strains of the human papilloma virus.)
- Hormonal birth control may slightly increase the risk of breast cancer, especially among younger women. Still, this link hasn’t been firmly established.
What’s the debate about hormonal birth control and breast cancer risk?
There could be a slight increase in breast cancer risk from hormonal birth control, but the study results have been mixed.
- A review of 54 studies in 1996 found that women have a slightly higher risk of breast cancer while taking birth control pills that contain both estrogen and progestin and during the 10 years after they stop taking the pills. Progestin-only pills also increased risk, but less so.
- A large 2002 study found that current or past use of birth control pills didn’t increase the risk of breast cancer in women aged 35 to 64. But the researchers noticed a small increase in risk among women aged 35 to 44 who used birth control pills and had a family history of breast cancer.
- A 2010 analysis of the Nurses’ Health Study found that past use of any oral contraceptive was not related to breast cancer risk. But results also suggested that current use slightly increased risk. The increased risk occurred mostly among women taking a “triphasic” pill, in which the dose of hormones changes over three stages of the monthly cycle.
- A 2012 analysis of the research on risk factors for breast cancer in women aged 40 to 49 years found that current use of hormonal contraceptives slightly increased risk.
Based on the current evidence, the World Health Organization and other medical groups tell women who’ve been diagnosed with breast cancer or who have a higher-than-average risk of the disease to avoid hormonal birth control. This includes all forms of birth control that use hormones, including the birth control patch, ring, injections (Depo-Provera), and implants, as well as progestin-only pills.
Women who start out with a higher-than-average risk of breast cancer may have an increased risk of breast cancer from taking hormonal contraceptives. This includes women with a family history of breast cancer and women with abnormal BRCA1 and BRCA2 genes. Making a higher-than-average risk a little higher isn’t a good idea for these women.
Age also plays into the safety profile of hormonal contraception. That’s because both breast cancer risk and the risks of hormonal contraception go up with age. If you’re young, your risk of breast cancer is relatively low. So taking hormonal contraception while you’re young and at low risk for breast cancer is considered relatively safe. (You can also get the anti-ovarian cancer benefit of 5 years of hormonal contraception when you’re young.) But as you grow older, your risk of breast cancer goes up and your risk of serious complications, such as blood clots, from hormonal contraceptives also goes up.
When your risk is higher for any reason, including being older, then you want to be more careful to avoid anything that could make that risk even higher. So, taking a drug that increases a higher risk of breast cancer even a little bit can add up to more risk. That’s why hormonal contraception isn’t recommended for women who’ve had breast cancer.
Are there other worries about hormonal contraceptives?
Early on, the high doses of hormones in birth control pills were associated with a relatively high risk of serious health problems in some women, including stroke, heart attack, and blood clots in the lungs (pulmonary embolism). But once the dose of hormones in birth control pills was lowered, these side effects have become much less common.
Still, hormonal contraceptives can cause a small but real increase in the risk of heart attack and stroke. Heart attacks happen when a blood clot blocks the flow of blood through part of the heart. Strokes happen when a blood clot blocks a blood vessel in the brain.
The higher risk of blood clots is because of the estrogen and progestin in hormonal contraception. Estrogen boosts levels of clotting factors in blood and progestin relaxes blood vessels. Together, these actions increase the likelihood that blood will pool in the veins and clot.
While the risk of heart attack and stroke is extremely low — less than 1% — in women who use hormonal birth control pills and have no other risk factors, it’s important to know that it still means twice as many heart attacks and strokes as in women who don’t use any type of hormonal contraception.
Also, the risk of heart attack and stroke goes up as we age, particularly in women 35 and older. It also goes up with certain conditions that increase the risk of blood clots, including high blood pressure, diabetes, migraine with aura, a history of blood clots, being extremely overweight, and smoking. Some women with these conditions may still be able to use some kinds of hormonal contraception, but need to talk to their doctors to find the best type for their situation.
Also, some people think that hormonal birth control can cause other significant but less serious side effects, including moodiness and a diminished sex drive. As with the other concerns, it’s difficult to clearly link these side effects directly to hormonal birth control.
Of course, individual women can have own their unique side effects with any medication.
Alternatives to the pill
Safe and effective birth control is critically important for millions of women. Birth control is particularly important for sexually active women who are currently being treated for breast cancer and may be fertile. Even if your periods may have stopped within the past year, it may be temporary. You may still be fertile and could possibly get pregnant at any time. It’s important not to get pregnant during treatment and for a period of time after.
You may be wary of switching from hormonal birth control to a non-hormonal version. But easy, effective, and safe alternatives to hormonal contraceptives do exist. Here are some options:
- Many doctors recommend using barrier methods of birth control. Condoms or a diaphragm are good options for most women. Still, the latex in some condoms may irritate the vagina in some women and make using them uncomfortable. A diaphragm is a good alternative and is effective if used properly. A diaphragm is used along with a spermicide, which also can help with lubrication. If the spermicide irritates your vagina, you can rinse the vagina out with water 5 hours after intercourse, after removing the diaphragm (you can use plain warm tap water in a small portable douche bag with a nozzle that you insert into the vagina). A water rinse limits the amount of time that your vagina is in contact with the spermicide. But I don’t recommend douching on a regular basis because it changes the natural acidic balance of your vagina, which can leave you susceptible to harmful bacteria and infection.
- Another option is a non-hormonal intrauterine device (IUD) such as ParaGard. This copper IUD is highly effective for birth control, doesn’t carry the risk of added hormones, and works for 10 years after your doctor inserts it into your uterus. If you wish to become pregnant, it can be removed. (It’s best to avoid IUDs that use hormones, such as Mirena.) IUDs have a small risk of side effects, including heavier periods, cramps, and a slightly increased risk of pelvic inflammatory disease, but not cancer.
- If you’re at a time in your life when you’re absolutely certain you don’t want to expand your family now or in the future, permanent birth control is an option. For women, a surgical procedure can close the fallopian tubes, stopping eggs from entering the uterus where they could be fertilized. For men, vasectomy cuts and seals the tubes that carry sperm so there’s no longer any sperm in the semen.
No matter which type of birth control you decide to use, ask your doctor if you have any questions on how to use it effectively. Birth control is an important choice. It’s better to be safe than sorry and you do have options. Non-hormonal contraceptives may require more work, but they may be safer and better for your health and well-being. It’s also important to remember that hormonal birth control, IUDs, and the diaphragm provide no protection against sexually transmitted diseases (STDs). Using a condom is also very important for STD protection.
If you’ve been diagnosed with breast cancer and need to use birth control, which type do you use?