Birth control is any method used to prevent pregnancy. Options range from a daily pill to a device placed once and left in for years, and they work through different biological mechanisms: blocking sperm from reaching an egg, stopping ovulation so no egg is released, or changing the uterine environment to prevent implantation. With over a dozen methods available, choosing one comes down to how effective it is, how much maintenance it requires, and how it fits your body and life.
How Birth Control Prevents Pregnancy
Every contraceptive method targets at least one step in the process of conception. Hormonal methods primarily suppress ovulation, the monthly release of an egg from the ovaries. They also thicken cervical mucus so sperm can’t pass through, and thin the uterine lining to make implantation unlikely. Barrier methods physically block sperm from reaching the egg. Permanent surgical methods close off the tubes that eggs or sperm travel through. Some methods, like the copper IUD, create a chemical environment inside the uterus that’s toxic to sperm without using any hormones at all.
Hormonal Methods
Hormonal birth control delivers synthetic versions of the hormones your body naturally produces during the menstrual cycle. Combined methods contain both estrogen and progestin, while others use progestin alone. The delivery format determines how often you interact with it.
The combined pill is taken at the same time every day, typically for 21 to 24 active days followed by a short break. With typical, real-world use, about 9 out of 100 people on the pill become pregnant in a year. With perfect use, that drops to 0.3 out of 100. The progestin-only pill is also taken daily and has the same effectiveness numbers, but it works without estrogen, which makes it an option for people who can’t tolerate estrogen due to migraines with aura, high blood pressure, or other conditions.
The patch sticks to your skin and releases hormones through it. You apply a new one weekly for three weeks, then go patch-free during the fourth week. The vaginal ring works on a similar schedule: three weeks in, one week out. Both have the same 9% typical-use failure rate as the pill.
The injection is a progestin-only shot given every three months, either by a healthcare provider or self-administered. It’s slightly more effective than the pill in typical use, with a 6% failure rate, largely because there’s less room for human error.
Long-Acting Reversible Methods
If you want something you don’t have to think about daily, weekly, or even monthly, long-acting reversible contraceptives (LARCs) are the most effective reversible options available. They’re placed once and work for years.
The hormonal IUD is a small T-shaped device placed inside the uterus. It releases progestin locally, thickening cervical mucus so sperm can’t get through. Depending on the specific device, it lasts 4 to 5 years by FDA approval, though research from the contraceptive CHOICE study found the most common type remains effective for at least 7 years. The typical-use failure rate is just 0.2%, making it one of the most reliable methods on the market.
The copper IUD contains no hormones. Instead, the copper creates an inflammatory reaction inside the uterus that’s harmful to sperm. It’s approved for up to 10 years and has a typical-use failure rate of 0.8%.
The implant is a thin, flexible rod inserted under the skin of the upper arm. It releases progestin and lasts up to 3 years. Its failure rate is 0.05%, the lowest of any reversible method, essentially matching the effectiveness of sterilization.
Barrier Methods
Barrier methods physically prevent sperm from reaching the egg. They’re used only when you have sex, which means effectiveness depends heavily on consistent, correct use every time.
The male (external) condom, made from latex or synthetic materials, has an 18% typical-use failure rate but only 2% with perfect use. That gap reflects how often condoms are used inconsistently or incorrectly. Condoms are also the only contraceptive that reduces the risk of sexually transmitted infections, including HIV. The female (internal) condom offers some STI protection as well, though the evidence is more limited. Its typical-use failure rate is 21%.
The diaphragm is a shallow silicone cup placed over the cervix before sex and used with spermicide. It has a 12% typical-use failure rate. The cervical cap works similarly but is smaller. The sponge combines a physical barrier with spermicide and is available over the counter, but its effectiveness varies significantly: 12% failure in people who haven’t given birth, 24% in those who have, because the cervix changes shape after childbirth. None of these methods protect against STIs.
Emergency Contraception
Emergency contraception is a backup option used after unprotected sex or contraceptive failure. It’s not designed as a primary method. Two types of emergency contraceptive pills are widely available, and both work best the sooner you take them, within a 5-day window.
The more common type, a single-dose pill containing levonorgestrel, is available over the counter at pharmacies. A newer option, ulipristal acetate, requires a prescription. Both are similarly effective in the first 3 days after unprotected sex. Between days 3 and 5, ulipristal acetate is more effective. The copper IUD can also serve as emergency contraception if inserted within 5 days, and it doubles as ongoing birth control afterward.
Permanent Methods
Sterilization is intended to be permanent. For people with fallopian tubes, the most common procedure is laparoscopic tubal ligation, where the tubes are sealed, clipped, or cut through small abdominal incisions. Recovery takes about 48 to 72 hours, with mild abdominal soreness. The cumulative 10-year pregnancy rate is about 1.85%, which is higher than many people expect for a “permanent” method.
Vasectomy, for people with testes, involves sealing or cutting the tubes that carry sperm. It’s typically done with local anesthesia through a small puncture in the scrotum, and discomfort lasts 2 to 3 days. The failure rate is 0.15% with typical use, making it more effective than tubal ligation and one of the most reliable contraceptive methods overall. It’s also less invasive and carries fewer surgical risks.
Over-the-Counter Options
Most hormonal birth control in the U.S. requires a prescription, but that’s starting to change. The FDA approved the first nonprescription daily oral contraceptive, a progestin-only pill called Opill, making it available at drug stores, grocery stores, convenience stores, and online without needing to see a provider. Condoms, spermicides, sponges, and levonorgestrel emergency contraception have long been available without a prescription as well.
Common Side Effects of Hormonal Methods
Most side effects from hormonal birth control are mild and often improve after the first few months. The most frequently reported issue with combined pills is breakthrough bleeding, or spotting between periods. Nausea, headaches, breast tenderness, abdominal cramping, and changes in libido are also common. Progestin-only methods tend to cause fewer systemic side effects but more unpredictable bleeding patterns. Some progestin-only pill users also report acne flare-ups and ovarian cysts.
Serious risks are uncommon but real, particularly with combined (estrogen-containing) methods. Blood clots are the most significant concern, especially in the first year of use. A large meta-analysis found that combined pill users have about 1.7 times the risk of ischemic stroke and 1.6 times the risk of heart attack compared to non-users. These risks are substantially higher for smokers over 35, which is why combined hormonal contraception is not recommended for people in that group who smoke more than 15 cigarettes a day. People with a history of blood clots, certain clotting disorders, migraines with aura, or uncontrolled high blood pressure are also advised against combined methods. Hormonal birth control can raise blood pressure in 4% to 5% of otherwise healthy users.
Medical Uses Beyond Pregnancy Prevention
Hormonal birth control is widely prescribed for reasons that have nothing to do with preventing pregnancy. It’s a frontline treatment for painful periods, heavy menstrual bleeding, and irregular cycles. For people with polycystic ovary syndrome (PCOS), combined pills help manage two visible symptoms of excess androgens: acne and unwanted hair growth. The estrogen component stimulates production of a protein that binds to testosterone in the blood, reducing the amount of active testosterone circulating in the body. The progestin component blocks testosterone’s effects at the skin level. Together, they address both the cosmetic symptoms and the underlying hormonal imbalance.
Birth control is also used to manage endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, causing pain. And for people approaching menopause, combined pills can smooth out irregular cycles, reduce hot flashes, and help maintain bone density.
Comparing Effectiveness at a Glance
Effectiveness varies enormously across methods. The numbers below reflect the percentage of people who become pregnant in the first year of typical, real-world use:
- Implant: 0.05%
- Hormonal IUD: 0.2%
- Vasectomy: 0.15%
- Female sterilization: 0.5%
- Copper IUD: 0.8%
- Injection: 6%
- Pill, patch, or ring: 9%
- Male condom: 18%
- Female condom: 21%
- Withdrawal: 22%
- Fertility awareness methods: 24%
- No method: 85%
The pattern is clear: methods that require less day-to-day effort tend to be more effective, because they remove the chance of human error. The gap between typical and perfect use is smallest for LARCs and sterilization, where the two numbers are nearly identical, and largest for condoms and fertility awareness, where consistent, correct use makes a dramatic difference.