Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (1,241 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
A progestational and glucocorticoid hormone antagonist. Its inhibition of progesterone induces bleeding during the luteal phase and in early pregnancy by releasing endogenous prostaglandins from the endometrium or decidua. As a glucocorticoid receptor antagonist, the drug has been used to treat hypercortisolism in patients with nonpituitary cushing syndrome.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: ZK-98296; ZK 98296; ZK98296; R-38486; R 38486; R38486; RU-38486; RU38486.
Where it fits in the MeSH classification
- Broader topics
- Estrenes
Related concepts
- Cushing Syndrome
Research landscape
PubMed indexes 6,775 records tagged with the MeSH heading “Mifepristone” (counts retrieved 2026-10-31). 797 of them (11.8%) were published from 2020 onward, and the busiest period so far is through 1999 with 2,493 records.
Reviews account for 622 records (9.2%) and meta-analyses for 68. Randomized controlled trials number 424 (6.3%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 2,493 |
| 2000-2009 | 1,972 |
| 2010-2019 | 1,513 |
| 2020 onward | 797 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 622 | 9.2% |
| Meta-analyses | 68 | 1.0% |
| Randomized controlled trials | 424 | 6.3% |
Method: PubMed query "Mifepristone"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in drugs and chemicals
Studies of a chemical or drug can answer very different questions: what it is and how it behaves in cells and animals, how the body handles it, and whether it changes outcomes in people. Laboratory and animal findings often do not carry over to patients, and observational studies of exposures are confounded by who uses a substance and why. Nothing on this page is a recommendation to use, avoid, start or stop any substance or medicine; talk to a qualified clinician or pharmacist about your own situation. Check the dose, the species, the comparison group and whether a patient-relevant outcome was measured.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Self-managed medication abortion outcomes: results from a prospective pilot study | 2020 | Research article Design not recorded in structured metadata | 53 | cc by PMID 33109230 · DOI · PMC7588945 |
| A single-day treatment with mifepristone is sufficient to normalize chronic glucocorticoid induced suppression of hippocampal cell proliferation | 2012 | Research article Design not recorded in structured metadata | 42 | cc by PMID 23049985 · DOI · PMC3458013 |
| Transient Prepubertal Mifepristone Treatment Normalizes Deficits in Contextual Memory and Neuronal Activity of Adult Male Rats Exposed to Maternal Deprivation | 2017 | Research article Design not recorded in structured metadata | 35 | cc by PMID 29098176 · DOI · PMC5666324 |
| Trends in Abortion Rates in Ontario, Canada | 2025 | Research article Design not recorded in structured metadata | 3 | cc by PMID 40214991 · DOI · PMC11992605 |
Self-managed medication abortion outcomes: results from a prospective pilot study [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundTo evaluate the feasibility of conducting a prospective study to measure self-managed medication abortion outcomes, and to collect preliminary data on safety and effectiveness of self-managed medication abortion, we recruited callers to accompaniment groups (volunteer networks that provide counselling through the out-of-clinic medication abortion process by trained counselors over the phone or in-person).
- Closing excerpt
- Trial registration ISRCTN95769543.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (276 words)
BackgroundTo evaluate the feasibility of conducting a prospective study to measure self-managed medication abortion outcomes, and to collect preliminary data on safety and effectiveness of self-managed medication abortion, we recruited callers to accompaniment groups (volunteer networks that provide counselling through the out-of-clinic medication abortion process by trained counselors over the phone or in-person).MethodsIn 2019, we enrolled callers to three abortion accompaniment groups in three countries into a prospective study on the safety and effectiveness of self-managed medication abortion with accompaniment support. Participants completed up to five interview-administered questionnaires from baseline through 6-weeks after taking the pills. Primary outcomes included: (1) the number of participants enrolled in a 30-day period, (2) the proportion that had a complete abortion; and (3) the proportion who experienced any warning signs of potential or actual complications.ResultsOver the 30-day recruitment period, we enrolled 227 participants (95% of those invited), and retained 204 participants (90%) for at least one study follow-up visit. At the 1-week follow-up, two participants (1%) reported a miscarriage prior to taking the pills, and 202 participants (89% of those enrolled and 99% of those who participated in the 1-week survey) had obtained and taken the medications. Three weeks after taking the medications, 192 (95%) participants reported feeling that their abortion was complete. Three (1.5%) received a surgical intervention, two (1%) received antibiotics, and five (3%) received other medications. Participants did not report any major adverse events.ConclusionThese results establish the feasibility of conducting prospective studies of self-managed medication abortion in legally restrictive settings. Further, the high effectiveness of self-managed medication abortion with accompaniment support reported here is consistent with high levels of effectiveness reported in prior studies. Trial registration ISRCTN95769543.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 33109230 · DOI · PMC7588945
A single-day treatment with mifepristone is sufficient to normalize chronic glucocorticoid induced suppression of hippocampal cell proliferation [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundChronic stress or prolonged administration of glucocorticoids suppresses proliferation and/or survival of newborn cells in adult rat dentate gyrus.
- Closing excerpt
- ConclusionsOur results emphasize that studies into the therapeutical efficacy of new antidepressants, especially those targeting HPA-activity or the glucocorticoid receptor, should explore the possibility to reduce treatment duration.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (186 words)
BackgroundChronic stress or prolonged administration of glucocorticoids suppresses proliferation and/or survival of newborn cells in adult rat dentate gyrus. Earlier we showed that administration of the glucocorticoid receptor antagonist mifepristone during the final 4 days of a 21 days period of corticosterone treatment fully normalized the number of newborn cells. Here we aimed to better understand how mifepristone achieves this effect and questioned whether an even shorter (single day) mifepristone treatment (instead of 4 days) also suffices to normalize neurogenesis.MethodsWe investigated various steps of the neurogenic process, using the immunohistochemical markers BrdU, doublecortin, proliferating cell nuclear antigen as well as glial fibrillary acidic protein, after 17 or 21 days of corticosterone (versus vehicle) treatment.ResultsCorticosterone primarily attenuates the proliferation of cells which subsequently develop into neurons; this is fully reversed by mifepristone. Surprisingly, the corticosteroid effects on neurogenesis can even be fully re-set by a single-day treatment with mifepristone (on day 18), despite the continued corticosterone exposure on subsequent days.ConclusionsOur results emphasize that studies into the therapeutical efficacy of new antidepressants, especially those targeting HPA-activity or the glucocorticoid receptor, should explore the possibility to reduce treatment duration.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 23049985 · DOI · PMC3458013
Transient Prepubertal Mifepristone Treatment Normalizes Deficits in Contextual Memory and Neuronal Activity of Adult Male Rats Exposed to Maternal Deprivation [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Early life adversity is a well-known risk factor for behavioral dysfunction later in life, including the formation of contextual memory; it is also (transiently) accompanied by hyperactivity of the stress system.
- Closing excerpt
- We conclude that transient prepubertal MIF treatment normalizes hippocampus-striatal-dependent contextual memory/spatial learning deficits in male rats exposed to early life adversity, possibly by normalizing glutamatergic transmission.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (247 words)
Early life adversity is a well-known risk factor for behavioral dysfunction later in life, including the formation of contextual memory; it is also (transiently) accompanied by hyperactivity of the stress system. We tested whether mifepristone (MIF) treatment, which among other things blocks glucocorticoid receptors (GRs), during the prepubertal period [postnatal days (PND)26-PND28] normalizes memory deficits in adult male rats exposed to 24-h maternal deprivation (MD) at PND3. MD reduced body weight gain and increased basal corticosterone (CORT) levels during the PND26, but not in adulthood. In adulthood, contextual memory formation of MD compared to noMD (i.e., control) male rats was significantly impaired. This impairment was fully prevented by MIF treatment at PND26-PND28, whereas MIF by itself did not affect behavior. A second behavioral test, a rodent version of the Iowa Gambling Task (rIGT), revealed that flexible spatial learning rather than reward-based aspects of performance was impaired by MD; the deficit was prevented by MIF. Neuronal activity as tested by c-Fos staining in the latter task revealed changes in the right hippocampal-dorsomedial striatal pathway, but not in prefrontal areas involved in reward learning. Follow-up electrophysiological recordings measuring spontaneous glutamate transmission showed reduced frequency of miniature postsynaptic excitatory currents in adult CA1 dorsal hippocampal and enhanced frequency in dorsomedial striatal neurons from MD versus noMD rats, which was not seen in MIF-treated rats. We conclude that transient prepubertal MIF treatment normalizes hippocampus-striatal-dependent contextual memory/spatial learning deficits in male rats exposed to early life adversity, possibly by normalizing glutamatergic transmission.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29098176 · DOI · PMC5666324
Trends in Abortion Rates in Ontario, Canada [4]
Abstract reading summary — source excerpts
- Opening excerpt
- ImportanceFollowing decades-long declines, significant increases in abortion rates have been reported in some jurisdictions from 2020 to 2023, but it is not yet known whether these trends are occurring in Canada.
- Closing excerpt
- Future research is needed to understand how sociocultural changes affecting abortion service use elsewhere may be affecting contraception access and use and thus abortion rates in Canada.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (532 words)
ImportanceFollowing decades-long declines, significant increases in abortion rates have been reported in some jurisdictions from 2020 to 2023, but it is not yet known whether these trends are occurring in Canada.ObjectiveTo assess abortion rates in Ontario from 2012 to 2022 and to examine trend changes associated with mifepristone availability, the COVID-19 pandemic, and postpandemic periods.Design, setting, and participantsThis population-based interrupted time series cohort study examined all medication and procedural abortions provided in Ontario from January 1, 2012, to December 31, 2022, to females aged 15 to 44 years with provincial insurance coverage, identified using linked health administrative data that included records from practitioner billings, inpatient and outpatient hospital services, same-day surgeries, and outpatient prescription dispensations.ExposureAvailability of mifepristone regulated as a normal (ie, prescribed by an authorized prescriber without additional certification or registration and dispensed by a pharmacist) prescription medication (in November 2017) and the COVID-19 pandemic period (from March 2020 to December 2021).Main outcomes and measuresThe main outcome was the abortion rate (number of abortions per 1000 females per year) overall and within age strata, using an interrupted time series design.ResultsOf 422 867 medication and procedural abortions identified using data from health records of 225 540 reproductive-aged females (mean [SD] age, 28.5 [6.6] years), the abortion rate declined steadily from 15.6 abortions per year per 1000 females, aged 15 to 44 years, in 2012 to 12.3 in 2021 and then increased to 14.1 in 2022. When mifepristone was introduced in 2017 as a normal prescription medication, no immediate change in the abortion rate (-0.1 [95% CI, -0.7 to 0.8]) and a nonsignificant slope increase (0.6 [95% CI, -0.5 to 0.7]) were found. However, this trend resulted in an additional 1.5 (95% CI, 0.3-2.6) abortions per 1000 females by the first quarter of 2020 compared with premifepristone trends; rates increased more among those aged 15 to 19 years, less among those aged 35 to 44 years, and did not increase for those aged 25 to 29 years. During the pandemic period, abortion rates decreased by 1.2 (95% CI, -2.5 to -0.8), most pronounced among those aged 20 to 34 years. Compared with expected rates based on premifepristone trends, 5-year availability of normally prescribed mifepristone was associated with a rate difference of 1.9 (95% CI, 0.7-5.4) in 2022, with a greater increase among those aged 20 to 24 years (4.2 [95% CI, 1.5-9.0]) and no change among those aged 25 to 29 years (1.0 [95% CI, -1.7 to 6.2]). The increased abortion rate in 2022 was consistent with 5-year trends following normally prescribed mifepristone, although social forces potentially impacting international rates may have contributed.Conclusions and relevanceThis study found that, following longstanding declines, abortion rates in Ontario gradually increased with mifepristone availability in 2017 in Ontario. Following a pandemic-related decrease in rates (in 2020 and 2021), substantial increases in abortion rates reported elsewhere from 2020 to 2023 did not occur in Ontario as of 2022, suggesting that Ontario's health services environment and Canada's regulatory and policy approach to preserving reproductive health services may have helped stabilize abortion rates. Future research is needed to understand how sociocultural changes affecting abortion service use elsewhere may be affecting contraception access and use and thus abortion rates in Canada.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 40214991 · DOI · PMC11992605
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article RU486 (mifepristone): mechanisms of action and clinical uses [5]
- Research article Progesterone withdrawal: key to parturition [6]
- Research article Mifepristone (RU 486)--a modulator of progestin and glucocorticoid action [7]
- Research article First-trimester medical abortion with mifepristone 200 mg and misoprostol: a systematic review [8]
- Research article Mifepristone With Buccal Misoprostol for Medical Abortion: A Systematic Review [9]
- Research article Mifepristone (RU486): a review [10]
References
- Moseson H, Jayaweera R, Raifman S, Keefe-Oates B, Filippa S, Motana R, et al.. Self-managed medication abortion outcomes: results from a prospective pilot study. . 2020. PMID 33109230 · DOI · PMC7588945
- Hu P, Oomen C, van Dam AM, Wester J, Zhou JN, Joëls M, et al.. A single-day treatment with mifepristone is sufficient to normalize chronic glucocorticoid induced suppression of hippocampal cell proliferation. . 2012. PMID 23049985 · DOI · PMC3458013
- Loi M, Sarabdjitsingh RA, Tsouli A, Trinh S, Arp M, Krugers HJ, et al.. Transient Prepubertal Mifepristone Treatment Normalizes Deficits in Contextual Memory and Neuronal Activity of Adult Male Rats Exposed to Maternal Deprivation. . 2017. PMID 29098176 · DOI · PMC5666324
- Schummers L, Dunn S, Cheng L, Norman WV. Trends in Abortion Rates in Ontario, Canada. . 2025. PMID 40214991 · DOI · PMC11992605
- Cadepond F, Ulmann A, Baulieu EE. RU486 (mifepristone): mechanisms of action and clinical uses. Annu Rev Med. 1997. PMID 9046951 · DOI
- Zakar T, Hertelendy F. Progesterone withdrawal: key to parturition. Am J Obstet Gynecol. 2007. PMID 17403397 · DOI
- Spitz IM, Bardin CW. Mifepristone (RU 486)--a modulator of progestin and glucocorticoid action. N Engl J Med. 1993. PMID 8326975 · DOI
- Raymond EG, Shannon C, Weaver MA, Winikoff B. First-trimester medical abortion with mifepristone 200 mg and misoprostol: a systematic review. Contraception. 2013. PMID 22898359 · DOI
- Chen MJ, Creinin MD. Mifepristone With Buccal Misoprostol for Medical Abortion: A Systematic Review. Obstet Gynecol. 2015. PMID 26241251 · DOI
- Mahajan DK, London SN. Mifepristone (RU486): a review. Fertil Steril. 1997. PMID 9418681 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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