Levonorgestrel

Levonorgestrel is a hormonal medication which is used in many birth control methods (sold under the brand names Plan B One-Step and Julie, among others). It is combined with an estrogen to make combination birth control pills. As an emergency birth control, it is useful within 72 hours of unprotected sex.

The more time that has passed since sex, the less effective the medication becomes. It should be taken as soon as possible after sex to prevent pregnancy. The drug (Plan B) is less effective in more overweight people, and it will not work as well if the person weighs more than 165lbs (74.8kg). Note that other forms of birth control (like a Copper IUD or cervical implant) are still effective above this weight. Ella (birth control) is more suited for people above 195lbs. It can be taken even if the combined oral contraceptive pill can not. Levonorgestrel does not work after pregnancy (implantation) has happened.

Levonorgestrel works by preventing ovulation or fertilization from happening. It decreases the chances of pregnancy by 57–93%.

References

  1. ↑ "Progestins (Etonogestrel, Levonorgestrel, Norethindrone)". The American Society of Health-System Pharmacists. Archived from the original on 2015-09-07. Retrieved Aug 21, 2015.
  2. ↑ Postgraduate Gynecology. Jaypee Brothers Medical Pub. 2011. p. 159. ISBN 9789350250822. Archived from the original on 2015-09-26.
  3. ↑ "Levonorgestrel 1.5 mg Tablet Emergency Contraceptive: New Drug Application 21998, Supplement 5" (PDF). U.S. Food and Drug Administration.
  4. ↑ "How to take the emergency contraceptive pill (morning after pill)". nhs.uk. 2024-02-29. Retrieved 2025-10-22.
  5. ↑ "What's the weight limit for Plan B?". www.plannedparenthood.org. Retrieved 2025-10-22.
  6. ↑ "Who can take the emergency contraceptive pill (morning after pill)". nhs.uk. 2024-02-29. Retrieved 2025-10-22.
  7. ↑ "Now Is the Time to Change Label on Emergency Contraceptives". Relias Media | Online Continuing Medical Education | Relias Media - Continuing Medical Education Publishing. Archived from the original on 2022-05-24. Retrieved 2022-08-16.
  8. ↑ Gemzell-Danielsson K (November 2010). "Mechanism of action of emergency contraception". Contraception. 82 (5): 404–409. doi:10.1016/j.contraception.2010.05.004. PMID 20933113.