Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on February 15th, 2026.
Plan B is most effective when taken within 24 hours of unprotected sex
Emergency contraception prevents pregnancy, it does not terminate an existing pregnancy
Different types of morning-after pills have varying effectiveness rates
Consultation with a healthcare provider can help determine the best option
Emergency contraception provides a critical option for individuals who want to prevent unintended pregnancy after potential contraceptive failure or unprotected sexual activity. The birth control pills landscape has evolved significantly, offering multiple emergency intervention methods.
While many people feel anxious about emergency contraception, understanding how these medications work can help reduce stress and enable informed decision making. Plan B and similar morning-after pills are designed to be a backup method, not a primary form of birth control.
Emergency contraception works by preventing or delaying ovulation, which means stopping an egg from being released from the ovary. If no egg is available for fertilization, pregnancy cannot occur. The effects of ethinyl estradiol in some emergency contraception can impact hormone levels and reproductive processes.
These over-the-counter medications include brands like Plan B One-Step. They are most effective when taken within 72 hours of unprotected intercourse, with peak effectiveness in the first 24 hours. The success rate drops from approximately 94% to 58% as time passes.
Available by prescription, this option extends the window of effectiveness to 120 hours (five days) after unprotected sex. Studies indicate it maintains high effectiveness, reaching up to 98% when taken promptly.
Medication Type |
Time Window |
Effectiveness |
Availability |
|---|---|---|---|
Levonorgestrel |
72 hours |
58-94% |
Over-the-counter |
Ulipristal |
120 hours |
85-98% |
Prescription |
Combination Birth Control |
72 hours |
Lowest efficacy |
Prescription |
Most individuals experience minimal side effects with emergency contraception. Common experiences include temporary changes in menstrual cycle, fatigue, dizziness, nausea, headache, abdominal pain, and slight breast tenderness. If you're taking medications that might interact, consulting a healthcare provider is recommended.
Emergency contraception does not protect against sexually transmitted infections. It's a one-time intervention designed to prevent pregnancy. For ongoing protection, discuss long-term contraceptive options with a healthcare professional.
Take it as soon as possible, ideally within 24 hours of unprotected sex for maximum effectiveness.
No, it prevents pregnancy by delaying ovulation. It will not terminate an existing pregnancy.
While safe, it's not recommended as a regular contraceptive method. Consult a healthcare provider for sustainable birth control options.
In most regions, Plan B is available without age restrictions, but local regulations vary.
Coverage differs. Many insurance plans cover prescription medications like emergency contraception.
Emergency contraception offers a crucial reproductive health option. Understanding its mechanisms, effectiveness, and proper use can help individuals make informed choices about their sexual health.
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Emergency contraception provides a critical option for individuals who want to prevent unintended pregnancy after potential contraceptive failure or unprotected sexual [...]
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