FDA Updates the Label of a Levonorgestrel Emergency Contraceptive on How It Works (2022)

In December 2022 the U.S. Food and Drug Administration (FDA) revised the labeling of a nonprescription emergency contraceptive, a single 1.5 mg tablet of levonorgestrel, to change what it says about how the medicine works. After reviewing a request from the company that holds the product’s application and “additional scientific evidence,” the FDA concluded that the tablet works by inhibiting or delaying ovulation and that there is “no direct effect on fertilization or implantation.” Wording about fertilization and implantation was taken off the package’s Drug Facts label.

This page reports what the FDA’s own information page on the product says: what changed and why, what the FDA concluded about how the tablet works, its answer on pregnancy and abortion, which label statements stay, what happens to the generic versions, what the update does not do, its status as of October 18, 2026, and how it fits the product’s earlier FDA history. The product is described here only by its active ingredient; no brand or company is named. Related conditions are covered on the site’s Reproductive Medicine pages.

Table of Contents

  1. What the FDA Did in December 2022
  2. The Product: One 1.5 mg Levonorgestrel Tablet
  3. What Changed on the Label and Leaflet
  4. What the FDA Concluded About How It Works
  5. Pregnancy, Implantation and the Abortion Question
  6. Label Statements That Stay
  7. The Generic Versions
  8. What the FDA Says About Timing and Effectiveness
  9. What the Update Does Not Do
  10. Dates and Legal Status as of October 18, 2026
  11. How It Fits Earlier and Later FDA Actions
  12. Primary Documents
  13. Key Research Papers
  14. Connections
  15. Featured Videos

1. What the FDA Did in December 2022

The FDA’s information page on the product, whose content is dated December 23, 2022, explains the step in a question-and-answer section headed “Why was the mechanism of action modified on the Drug Facts label and Consumer Information Leaflet in 2022?” The mechanism of action is the way a medicine produces its effect in the body.

The page sets out the sequence:

The FDA page links a supplemental approval letter and a decisional memorandum for the action. Neither could be read for this page, so the exact day the FDA approved the labeling supplement is not given here; December 2022 is the month of the information page that announced it.

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2. The Product: One 1.5 mg Levonorgestrel Tablet

The FDA page describes the product as “an emergency contraceptive, a backup method to other birth control.” It is “in the form of one levonorgestrel pill (1.5 mg) that is taken by mouth after unprotected sex or contraceptive failure.” The page adds that “Levonorgestrel is a synthetic hormone used in birth control pills for over 35 years,” and that the product “is available as a nonprescription (over-the-counter or OTC) drug.”

On emergency contraception in general, the FDA page states:

The page also compares the tablet with ordinary birth control pills: it “contains a higher dose of levonorgestrel than birth control pills and works in a similar way to prevent pregnancy.”

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3. What Changed on the Label and Leaflet

A nonprescription medicine carries two kinds of written information that matter here:

The FDA page describes two changes:

  1. Drug Facts label. The FDA “removed information directly related to the mechanism of action from the ‘Other Information’ section of the Drug Facts label.” The page’s own heading for this answer describes the change as removing “wording about fertilization and implantation.”
  2. Consumer Information Leaflet. The FDA “updated the mechanism of action information in the Consumer Information Leaflet, which included removing references to the mechanisms not supported by the best available scientific evidence (that is, effects on fertilization and implantation).”

The page explains why the mechanism was moved off the package label rather than kept there. “The mechanism of action is rarely included in nonprescription drug labeling (and, more specifically, the Drug Facts label) and is not required under FDA’s regulations for nonprescription labeling, as this information is not needed for the safe and effective use of nonprescription drugs in general.” It continues: “Because consumers may be interested in how” the product works, “information on the mechanism was kept in the Consumer Information Leaflet and updated to be consistent with the best available evidence.”

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4. What the FDA Concluded About How It Works

The central finding is stated twice on the FDA page, once for each part of the labeling. For the Drug Facts label: “FDA determined the current science supports a conclusion that [the product] works by inhibiting or delaying ovulation and the midcycle hormonal changes. The evidence also supports the conclusion that there is no direct effect on fertilization or implantation.”

For the leaflet the wording is slightly broader: the evidence “supports the conclusion that there is no direct effect on postovulatory processes, such as fertilization or implantation.”

Three of the terms in plain words:

“Postovulatory processes” are the steps that come after ovulation, such as fertilization and implantation.

The updated leaflet, as the FDA page describes it, now explains that the product “works before release of an egg from the ovary. As a result, [it] usually stops or delays the release of an egg from the ovary.” The same two sentences open the FDA page’s own answer to the question “How does [it] work?”

The FDA’s scientific reasoning is set out in more detail in the decisional memorandum linked from its page. That memorandum was not read for this page and is not quoted here.

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5. Pregnancy, Implantation and the Abortion Question

The FDA page asks directly whether the product is “an abortifacient (causing abortion)” and answers:

“No. [It] will not work if a person is already pregnant, meaning it will not affect an existing pregnancy. [It] prevents pregnancy by acting on ovulation, which occurs well before implantation. Evidence does not support that the drug affects implantation or maintenance of a pregnancy after implantation, therefore it does not terminate a pregnancy.”

An abortifacient is a substance that ends an established pregnancy. The FDA’s answer rests on the same conclusion described in section 4: the tablet acts on ovulation, before fertilization and implantation take place, and the evidence the FDA reviewed does not show an effect after implantation.

The page connects this to the label’s existing pregnancy statements (section 6): because those statements say the tablet does not work in a person who is already pregnant, “when considering when in the reproductive cycle [it] might work, it will be clear to the consumer that [it] works very early in the reproductive cycle (prior to ovulation).”

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6. Label Statements That Stay

The FDA page states that “both the Drug Facts label and Consumer Information Leaflet retain statements that are consistent with the mechanism of action” and that they “continue to include information that relates to when in the reproductive cycle” the product works. It quotes the statements that remain, word for word:

These are the label’s own words as the FDA quotes them. The FDA page describes them as statements that “remind the consumer that [the product] does not work when a woman is already pregnant.”

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7. The Generic Versions

The FDA page states that there are “multiple (11) generics” of the product “with an active marketing status,” and that they “are approved for nonprescription use without age restrictions.”

It explains why the 2022 change reaches them too. “A generic drug is required to have the same labeling as the reference listed drug except for certain permissible differences, and generic drug holders are expected to update their labeling after FDA has approved relevant changes to the labeling for the corresponding reference listed drug.” The reference listed drug is the original approved product that generic versions are compared with; here, that is the 1.5 mg tablet whose label was changed.

The page concludes that the generics “are expected to update their labeling to reflect the changes made to the [product’s] labeling by submitting their revised labeling as soon as possible.” The FDA page does not say when each generic made the change, and that was not checked for this page.

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8. What the FDA Says About Timing and Effectiveness

The 2022 update concerned how the tablet works, not how well. The same FDA page, answering whether the product is effective, states: “The most important factor affecting how well emergency contraception works is how quickly it is taken after unprotected sex or contraceptive failure.”

From that, the FDA page sets out its own recommendations, given here as the FDA’s:

The page also invites consumers and health care professionals to report adverse reactions to the FDA’s MedWatch program (www.fda.gov/MedWatch, or 1-800-FDA-1088). Decisions about contraception belong with a clinician or pharmacist.

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9. What the Update Does Not Do

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10. Dates and Legal Status as of October 18, 2026

Status as of October 18, 2026: the revised labeling is in effect. The Federal Register is the U.S. government’s daily publication of rules and official notices. A check of FDA documents in it from mid-2022 through October 18, 2026, for the terms “levonorgestrel” and “emergency contraceptive,” returned only routine notices (guidance listings for generic drug studies, a 2025 advisory committee meeting notice, and notices withdrawing approval of batches of drug applications). None of them reverses or changes the 2022 mechanism-of-action labeling.

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11. How It Fits Earlier and Later FDA Actions

The FDA page gives a short history of the product line:

Each earlier step on the FDA’s list changed who could get the product and how; the 2022 step changed what its labeling says about how it works.

A later FDA action on nonprescription contraception is told on the site’s page FDA Approves the First Nonprescription Daily Birth Control Pill (2023). That page concerns a different medicine, a daily birth control pill, and reports that it is not for emergency use. Among other 2022 FDA drug actions, the FDA also warned of dental problems with buprenorphine dissolved in the mouth, another case of the agency changing what a label says about a medicine already on sale.

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12. Primary Documents

  1. U.S. Food and Drug Administration. (1.5 mg levonorgestrel) Information. Postmarket Drug Safety Information for Patients and Providers, content current as of December 23, 2022. Listed among the FDA’s Postmarket Drug Safety Information pages on fda.gov; its title and web address carry the product’s brand name, so it is given here as plain text without a link.
  2. U.S. Food and Drug Administration. The Over-the-Counter Drug Facts Label. Consumer information page, content current as of September 2, 2026 — fda.gov Over-the-Counter Drug Facts Label
  3. Federal Register, FDA documents from June 2022 through October 18, 2026 containing “levonorgestrel” or “emergency contraceptive”, checked through the federalregister.gov API on October 18, 2026 (status check; no document changing the 2022 labeling found) — federalregister.gov

The FDA page links three further documents that could not be read for this page and are not quoted: the product’s labeling on Drugs@FDA, the decisional memorandum, and the supplemental approval letter.

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Key Research Papers

  1. Gemzell-Danielsson K, Berger C, Lalitkumar PGL (2013). Emergency contraception – mechanisms of action. Contraception 87(3):300-308 — PubMed PMID: 23114735
  2. Durand M, del Carmen Cravioto M, Raymond EG, Durán-Sánchez O, De la Luz Cruz-Hinojosa M, Castell-Rodríguez A, Schiavon R, Larrea F (2001). On the mechanisms of action of short-term levonorgestrel administration in emergency contraception. Contraception 64(4):227-234 — PubMed PMID: 11747872
  3. Croxatto HB, Brache V, Pavez M, Cochon L, Forcelledo ML, Alvarez F, Massai R, Faundes A, Salvatierra AM (2004). Pituitary-ovarian function following the standard levonorgestrel emergency contraceptive dose or a single 0.75-mg dose given on the days preceding ovulation. Contraception 70(6):442-450 — PubMed PMID: 15541405
  4. Novikova N, Weisberg E, Stanczyk FZ, Croxatto HB, Fraser IS (2007). Effectiveness of levonorgestrel emergency contraception given before or after ovulation – a pilot study. Contraception 75(2):112-118 — PubMed PMID: 17241840
  5. Lalitkumar PG, Lalitkumar S, Meng CX, Stavreus-Evers A, Hambiliki F, Bentin-Ley U, Gemzell-Danielsson K (2007). Mifepristone, but not levonorgestrel, inhibits human blastocyst attachment to an in vitro endometrial three-dimensional cell culture model. Human Reproduction 22(11):3031-3037 — PubMed PMID: 17890724
  6. von Hertzen H, Piaggio G, Ding J, Chen J, Song S, Bártfai G, Ng E, Gemzell-Danielsson K, Oyunbileg A, Wu S, Cheng W, Lüdicke F, Pretnar-Darovec A, Kirkman R, Mittal S, Khomassuridze A, Apter D, Peregoudov A; WHO Research Group on Post-ovulatory Methods of Fertility Regulation (2002). Low dose mifepristone and two regimens of levonorgestrel for emergency contraception: a WHO multicentre randomised trial. Lancet 360(9348):1803-1810 — PubMed PMID: 12480356
  7. Shen J, Che Y, Showell E, Chen K, Cheng L (2019). Interventions for emergency contraception. Cochrane Database of Systematic Reviews 1(1):CD001324 — PubMed PMID: 30661244

The first five papers concern the question at the center of the 2022 labeling change: how levonorgestrel emergency contraception works. They include a review of its mechanisms, studies of its effects on hormones, the ovary and the lining of the womb when given at different points in the cycle, a study comparing its effectiveness when taken before or after ovulation, and a laboratory study of embryo attachment to womb-lining cells. The last two concern effectiveness: a large randomized trial run by the World Health Organization comparing levonorgestrel regimens, and the Cochrane systematic review of emergency contraception methods. None of the papers was written by the FDA or is cited by name on the FDA’s information page.

PubMed Topic Searches

  1. PubMed: levonorgestrel emergency contraception mechanism of action
  2. PubMed: levonorgestrel emergency contraception and ovulation
  3. PubMed: levonorgestrel emergency contraception effectiveness

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Connections

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