Levonorgestrel
pharmaceutical drug
Levonorgestrel is a hormonal medication used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand names Plan B One-Step and Julie, among others, it is useful within 72 hours of unprotected sex. The more time that has passed since sex, the less effective the medication becomes. Levonorgestrel works by preventing or delaying ovulation so an egg cannot be released. The dosage used for emergency contraception is ineffective when ovulation has already occurred, and has been found to have no effect on implantation. It decreases the chances of pregnancy by 57–93%. In an intrauterine device (IUD), such as Mirena among others, it is effective for the long-term prevention of pregnancy. A levonorgestrel-releasing implant is also available in some countries.
Common side effects include nausea, breast tenderness, headaches, and increased, decreased, or irregular menstrual bleeding.
“Levonorgestrel” enters the record as pharmaceutical drug. Crown Archives preserves that source wording while asking what Levonorgestrel, pharmaceutical and drug can confirm, complicate or overturn.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated May 4, 2026. The linked authority identifier is Q416950. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Levonorgestrel” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.