Birth control doesn’t have a simple yes-or-no relationship with cancer. Hormonal contraceptives modestly increase the risk of breast cancer while significantly lowering the risk of ovarian, endometrial, and colorectal cancers. For most women, the protective effects outweigh the risks, but the balance shifts depending on your age, how long you use contraception, and your personal risk factors.
Breast Cancer: A Small but Real Increase
Current or recent use of hormonal contraceptives raises breast cancer risk by roughly 20% to 30%. That applies to combined pills (estrogen plus progestin), progestin-only pills, hormonal IUDs, implants, and injectable contraceptives. A large UK study found the increase was essentially the same regardless of which type of hormonal method was used, with no meaningful difference between combined and progestin-only options.
To put that 20% to 30% in perspective: breast cancer is uncommon in younger women, so a small percentage increase on a small baseline number translates to very few additional cases. For a 30-year-old, the absolute risk of developing breast cancer in the next 10 years is about 0.5%. A 25% relative increase would push that to roughly 0.6%. The picture changes for women in their 40s, when baseline breast cancer rates are higher and the same relative increase produces more additional cases.
The reassuring part is that this elevated risk fades after stopping. Research from the National Cancer Institute indicates that breast cancer risk returns to normal about 10 years after discontinuing the pill.
Why Hormones Affect Breast Tissue
Estrogen and progesterone receptors are abundant in breast cells. When activated by the hormones in contraceptives, these receptors switch on genes that drive cell growth, alter how cells process sugar and fats, and may awaken dormant precancerous cells. The combination of estrogen and progestin together appears to push cells toward characteristics associated with more aggressive growth patterns, including increased reliance on a type of rapid energy production typical of cancer stem cells. Once you remove the hormonal stimulus by stopping contraception, these effects wind down over time.
Ovarian Cancer: Strong, Lasting Protection
The most striking benefit of oral contraceptives is a 30% to 50% reduction in ovarian cancer risk. This protection grows the longer you take the pill and persists for up to 30 years after you stop. Because ovarian cancer is difficult to detect early and has a high mortality rate, this lasting reduction is one of the most clinically meaningful effects of oral contraceptive use.
Endometrial and Colorectal Cancer Risk Drops Too
Women who take combined oral contraceptives for at least one year cut their endometrial cancer risk roughly in half. This benefit is especially pronounced in women who haven’t had children, a group that otherwise faces a higher baseline risk for this type of cancer.
Oral contraceptive use is also linked to about a 19% reduction in colorectal cancer, based on pooled analyses of multiple studies. The mechanism isn’t fully understood, but it likely involves the way hormones influence the lining of the digestive tract.
Cervical and Liver Cancer: Worth Knowing About
Long-term oral contraceptive use is associated with a higher risk of cervical cancer, though this relationship is complicated by the role of HPV. Women who take the pill for longer periods may be more likely to have persistent HPV infections, which are the primary driver of cervical cancer. Regular cervical screening largely mitigates this risk.
Benign liver tumors are rare but clearly linked to pill use. The risk climbs with duration: after 3 to 5 years of use, it’s about 2.5 times higher than for short-term users. After 9 or more years, the risk jumps to 25 times higher. These tumors are almost always noncancerous, but they can occasionally cause complications. The link between oral contraceptives and malignant liver cancer is much weaker and mainly relevant for women who already have other liver disease risk factors.
BRCA Mutations Change the Equation
Women who carry BRCA1 or BRCA2 gene mutations face a dramatically elevated lifetime cancer risk. BRCA1 carriers have up to a 72% chance of developing breast cancer and up to a 44% chance of ovarian cancer by age 80. For BRCA2 carriers, those figures are about 69% and 17%, respectively.
Oral contraceptives do reduce ovarian cancer risk in BRCA carriers, just as they do in the general population. However, an increase in breast cancer risk from the pill cannot be ruled out in this group. Current guidance advises that BRCA carriers who are considering oral contraceptives should weigh the potential breast cancer risk against the ovarian cancer benefit and consider alternative contraceptive methods. Oral contraceptives should not be used solely to prevent ovarian cancer in BRCA carriers when contraception itself isn’t needed, because risk-reducing surgery remains the more effective option.
How the Risks and Benefits Balance Out
For most women of reproductive age, the cancers that hormonal contraceptives protect against (ovarian, endometrial, colorectal) are collectively more common and more deadly than the modest breast cancer risk increase. The ovarian cancer protection alone persists for decades after stopping the pill, meaning former users carry a benefit well into the age range where these cancers become more common.
Your individual calculation depends on several factors: your age, how long you plan to use contraception, your family history of breast or ovarian cancer, and whether you carry known genetic mutations. A woman in her 20s with no family history of breast cancer faces a very different risk profile than a 40-year-old BRCA1 carrier. The breast cancer risk increase is temporary and resolves within a decade of stopping, while the protective effects against ovarian and endometrial cancer last far longer. That asymmetry is why, in population-level analyses, long-term oral contraceptive use is generally associated with a net reduction in cancer-related deaths.