Levonorgestrel: Emergency contraception and birth control basics
What levonorgestrel does, how it works as emergency contraception or regular birth control, effectiveness rates, and what to expect from this progestin-based medication.
What levonorgestrel is
Levonorgestrel is a synthetic progestin used in two main ways: as emergency contraception taken after unprotected sex, and as a regular birth control method in pills, implants and other forms.
How it works
Levonorgestrel prevents pregnancy by stopping or delaying ovulation. When taken as emergency contraception, it's most effective within 72 hours of unprotected intercourse, though some formulations work up to 120 hours. As regular birth control, it works by thickening cervical mucus and thinning the uterine lining.
Effectiveness
As emergency contraception, levonorgestrel is about 60 to 90 percent effective at preventing pregnancy, depending on timing and body weight. Effectiveness drops as time passes after intercourse. As a regular birth control method, typical use effectiveness is around 91 percent when combined with other hormones in standard pills.
Getting levonorgestrel
Emergency contraception with levonorgestrel is available over the counter at pharmacies without age restrictions or prescription. Regular birth control containing levonorgestrel requires a prescription from a doctor or nurse practitioner. Many telehealth providers can prescribe birth control online after a brief medical history and questionnaire.
Side effects and considerations
Common side effects include nausea, headache, fatigue and irregular bleeding. Taking it with food can reduce nausea. Levonorgestrel is not as effective in people weighing over 165 to 175 pounds, depending on the formulation.
Getting care
For emergency contraception, visit a pharmacy or order online. For regular birth control prescriptions, talk to your primary care doctor, gynecologist or use an online telehealth service that offers contraceptive prescribing.