Contraception is any method used to prevent pregnancy. Options range from daily pills to devices that last over a decade, and they work through different biological mechanisms: blocking sperm, stopping ovulation, or both. There are five main categories: long-acting reversible contraception (LARC), hormonal methods, barrier methods, emergency contraception, and sterilization.
How Hormonal Methods Prevent Pregnancy
Hormonal contraceptives work primarily by stopping ovulation. The synthetic hormones in these methods send signals to the brain that reduce the release of the chemicals needed to develop and release an egg each month. Without a mature egg, pregnancy can’t happen.
That’s not the only line of defense. These hormones also thicken the mucus at the cervix, creating a barrier that makes it much harder for sperm to reach the upper reproductive tract. Some formulations slow the movement of the egg through the fallopian tubes and thin the uterine lining, adding additional layers of protection. This is why hormonal methods remain highly effective even when one mechanism doesn’t work perfectly on its own.
Hormonal options include the daily pill, patches, vaginal rings, injections, hormonal IUDs, and the subdermal implant. The pill has a 9% failure rate with typical use (meaning how people actually use it, with occasional missed doses or late timing), but only 0.3% with perfect use. That gap highlights how much user compliance matters with short-acting methods.
Long-Acting Reversible Contraception (LARC)
LARC methods are the most effective reversible options available. They include IUDs (both hormonal and copper) and the contraceptive implant, a small rod placed under the skin of the upper arm.
The implant is approved for 3 years, though research shows its effectiveness extends further. In studies tracking prolonged use, no pregnancies were reported among participants who kept the implant for one or two additional years beyond the approved duration. Its typical-use failure rate is 0.05%, making it the single most effective reversible contraceptive.
Hormonal IUDs are approved for up to 8 years, depending on the specific device. Studies following users for 6 to 15 years reported zero pregnancies, and their typical-use failure rate is 0.2%. The copper IUD, which contains no hormones and instead uses copper to create an environment toxic to sperm, is approved for 5 to 10 years. For people over 30 at the time of insertion, extended use of 12 to 20 years, or even to menopause, can be considered as a form of reversible, near-permanent contraception.
The major advantage of LARC methods is that they require no daily action. Once placed, they work continuously, which is why their typical-use and perfect-use failure rates are nearly identical.
Barrier Methods
Barrier methods physically block sperm from reaching the egg. The most common is the male condom, which has an 18% typical-use failure rate and a 2% perfect-use rate. Female condoms are slightly less effective, with a 21% typical-use failure rate. These numbers are significantly higher than hormonal or LARC methods, but condoms offer something no other contraceptive does: protection against sexually transmitted infections, including HIV.
Other barrier options include diaphragms and cervical caps, which cover the cervix and are typically used with spermicide. These are less popular today, as longer-acting methods have gained preference.
Emergency Contraception
Emergency contraception is a backup option used after unprotected sex, not a primary method. All emergency options should be used as soon as possible, and all can be effective within 5 days of unprotected intercourse.
Emergency contraceptive pills work best when taken quickly. One common type remains effective through day 4 but shows higher pregnancy rates at 4 to 5 days. Another type maintains consistent effectiveness through the full 5-day window. The copper IUD can also be placed within 5 days of unprotected sex as emergency contraception, and it doubles as a long-term method going forward.
Sterilization
Sterilization is intended to be permanent. Tubal surgery (for women) has a first-year failure rate of about 0.5%, and the procedure provides immediate protection. Vasectomy (for men) has a lower failure rate of 0.15% in the first year, but it doesn’t work immediately. Sperm remain in the reproductive tract for weeks after the procedure. By 12 weeks, about 80% of men have no sperm in their semen, but a follow-up semen analysis at 8 to 16 weeks is needed to confirm success. Until that confirmation, another method like condoms is necessary. Once confirmed, the risk of pregnancy drops to roughly 1 in 2,000.
Benefits Beyond Pregnancy Prevention
Hormonal contraceptives were originally approved by the FDA for treating menstrual disorders, not just preventing pregnancy. That history reflects how broadly useful they are. Oral contraceptives effectively treat heavy or irregular periods, severe menstrual cramps, and premenstrual syndrome. For people with endometriosis, they manage pain symptoms as effectively as more expensive alternatives, with fewer side effects and the ability to be used long-term.
Formulations with specific hormone types can treat acne, excess hair growth, and oily skin by counteracting the effects of androgens. Hormonal contraceptives also eliminate persistent ovarian cysts by fully suppressing the monthly hormonal cycle, preserve bone density, and reduce the frequency of menstrual migraines.
Perhaps most significant: long-term use substantially reduces the risk of ovarian, endometrial, and colon cancers. It also lowers the risk of pelvic inflammatory disease, delays the onset of multiple sclerosis in susceptible individuals, and helps control benign breast disease.
How the Right Method Gets Chosen
No single method is best for everyone. Medical eligibility depends on individual health conditions. The CDC’s 2024 guidelines cover dozens of conditions that influence which methods are safe, including blood clotting disorders, heart conditions, liver disease, kidney disease, lupus, sickle cell disease, obesity, and breastfeeding status. Certain medications, particularly some antiretrovirals, also interact with hormonal methods and require adjustments.
The broader trend is clear: interest in long-acting methods is rising sharply. An analysis of global search trends from 2004 to 2024 found that searches for IUDs and vasectomies increased significantly, while searches for birth control pills, condoms, and tubal ligation all declined. The shift reflects growing preference for methods that require less daily effort, offer higher effectiveness, and in the case of IUDs, remain fully reversible.