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Anovulation

Anatomy and Physiology · NLM MeSH · updated 2026-10-31 · version 1

Citations verified against PubMedNot yet clinician-reviewed10 referencesApproximately 5 min read

Suspension or cessation of ovulation in animals or humans with follicle-containing ovaries (ovarian follicle).

Table of Contents

1. Definition2. Research landscape3. Reading the evidence4. Open-access studies5. Key reviews6. References7. About this article

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 (1,050 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

Suspension or cessation of ovulation in animals or humans with follicle-containing ovaries (ovarian follicle). Depending on the etiology, ovulation may be induced with appropriate therapy.

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: Anovulations.

Where it fits in the MeSH classification

Broader topics
Ovarian Diseases; Ovulation

Related concepts

  • Ovulation
  • Ovarian Follicle

Research landscape

PubMed indexes 2,352 records tagged with the MeSH heading “Anovulation” (counts retrieved 2026-10-31). 147 of them (6.2%) were published from 2020 onward, and the busiest period so far is through 1999 with 1,359 records.

Reviews account for 429 records (18.2%) and meta-analyses for 33. Randomized controlled trials number 125 (5.3%) as a share of all records on the topic.

PubMed records by publication periodthrough 1999: 1,359 records; 2000-2009: 457 records; 2010-2019: 389 records; 2020 onward: 147 records1,359through 19994572000-20093892010-20191472020 onward
Records in PubMed indexed with this heading, by publication period. Real counts from NCBI E-utilities; the final period covers only part of the current year. Volume reflects how much has been published, not how strong the evidence is.
Show the data
PeriodRecords
through 19991,359
2000-2009457
2010-2019389
2020 onward147
Share of records by publication typeReviews: 18.2 percent; Meta-analyses: 1.4 percent; Randomized controlled trials: 5.3 percentReviews18.2% (429)Meta-analyses1.4% (33)Randomized controlled trials5.3% (125)
Share of all PubMed records on this heading that carry each publication type. Types overlap with other records, so the shares do not sum to 100%.
Publication-type chart data
Publication types among 2,352 PubMed records
TypeRecordsShare
Reviews42918.2%
Meta-analyses331.4%
Randomized controlled trials1255.3%

Method: PubMed query "Anovulation"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.

Reading the evidence in anatomy and physiology

Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.

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 comparison — selected abstracts, not a systematic review
Study / authorsYearSource label / designEurope PMC citationsLicence / source
Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome
Li C, Xing C, Zhang J, Zhao H, Shi W, He B
2021Clinical trial
Design not recorded in structured metadata
128cc by
PMID 33849562 · DOI · PMC8045367
Ovulation Prevalence in Women with Spontaneous Normal-Length Menstrual Cycles - A Population-Based Cohort from HUNT3, Norway
Prior JC, Naess M, Langhammer A, Forsmo S
2015Research article
Design not recorded in structured metadata
81cc by
PMID 26291617 · DOI · PMC4546331
Modulation of the Inflammatory Response in Polycystic Ovary Syndrome (PCOS)-Searching for Epigenetic Factors
Szukiewicz D, Trojanowski S, Kociszewska A, Szewczyk G
2022Review article
Design not recorded in structured metadata
51cc by
PMID 36498989 · DOI · PMC9736994
The Leucine-mTOR-Autophagy Axis in Granulosa Cells Mediates Circadian Disruption-Induced Anovulation
He R, Mo J, Lin Z, Zhu K, Wang Y, Yu J, et al.
2026Research article
Design not recorded in structured metadata
1cc by
PMID 41362744 · DOI · PMC12681872

Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome [1]

Clinical trial Li C, Xing C, Zhang J, Zhao H, Shi W, He B · · 2021 · cited 128 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
BackgroundTime-restricted feeding (TRF) is a form of intermittent fasting, which is beneficial for weight loss and cardiometabolic health.
Closing excerpt
gov/ct2/show/NCT04580433.
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 (277 words)

BackgroundTime-restricted feeding (TRF) is a form of intermittent fasting, which is beneficial for weight loss and cardiometabolic health. Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine and metabolic diseases affecting women of childbearing age. It is associated with an increased prevalence of metabolic syndrome, cardiovascular diseases and type 2 diabetes. The effects of TRF on PCOS patients remains undefined, here we investigated the impact of TRF on women with anovulatory PCOS.MethodsEighteen PCOS women aged between 18 and 31 with anovulation participated in a 6-week trial which were divided into two consecutive periods: (1) 1-week baseline weight stabilization period and (2) 5-week TRF period. Fifteen participants completed the study. Changes in body weight, body mass index (BMI), Waist-to-Hip Ratio, skeletal muscle mass, body fat mass (BFM), body fat percentage (BF%), visceral fat area (VFA), luteinizing hormone (LH), follicle-stimulating hormone (FSH), LH/FSH, total testosterone (TT), sex hormone-binding globulin (SHBG), free androgen index (FAI), fasting glucose, fasting insulin (FINS), homeostasis model assessment-insulin resistance (HOMA-IR), area under the curve (AUC) for insulin (AUCIns), area under the curve (AUC) for glucose (AUCGlu), AUCIns/AUCGlu Ratio, lipids, uric acid, alanine aminotransferase (ALT), aspartate aminotransferase, high-sensitivity C-reactive protein (hsCRP), insulin-like growth factor (IGF-1), menstrual cycle and eating behaviors were evaluated.ResultsSignificant changes in body weight, BMI, BFM, BF%, VFA, TT, SHBG, FAI, FINS, HOMA-IR, AUCIns, AUCIns/AUCGlu Ratio, ALT, hsCRP and IGF-1 were found after the TRF period. An improvement in menstrual cycle irregularity was detected in 73.3% (11/15) patients.ConclusionThe diet of TRF may be beneficial to anovulatory PCOS on weight loss especially reducing body fat, improving menstruation, hyperandrogenemia, insulin resistance and chronic inflammation. Trial registration Clinicaltrial.gov, NCT04580433, registered October 8, 2020, https://clinicaltrials.gov/ct2/show/NCT04580433.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 33849562 · DOI · PMC8045367

Ovulation Prevalence in Women with Spontaneous Normal-Length Menstrual Cycles - A Population-Based Cohort from HUNT3, Norway [2]

Research article Prior JC, Naess M, Langhammer A, Forsmo S · · 2015 · cited 81 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
BackgroundOvulatory menstrual cycles are essential for women's fertility and needed to prevent bone loss.
Closing excerpt
ConclusionAnovulation in a random population occurs in over a third of clinically normal menstrual cycles.
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 (294 words)

BackgroundOvulatory menstrual cycles are essential for women's fertility and needed to prevent bone loss. There is a medical/cultural expectation that clinically normal menstrual cycles are inevitably ovulatory. Currently within the general population it is unknown the proportion of regular, normal-length menstrual cycles that are ovulatory. Thus, the objective of this study was to determine the population point prevalence of ovulation in premenopausal, normally menstruating women. The null hypothesis was that such cycles are ovulatory.MethodsThis is a single-cycle, cross-sectional, population-based study-a sub-study of the HUNT3 health study in the semi-rural county (Nord Trøndelag) in mid-Norway. Participants included >3,700 spontaneously (no hormonal contraception) menstruating women, primarily Caucasian, ages 20-49.9 from that county. Participation rate was 51.9%. All reported the date previous flow started. A single, random serum progesterone level was considered ovulatory if ≥9.54 nmol/L on cycle days 14 to -3 days before usual cycle length (CL).ResultsOvulation was assessed in 3,168 women mean age 41.7 (interquartile range, [IQR] 36.8 to 45.5), cycle length 28 days (d) (IQR 28 to 28) and body mass index (BMI) 26.3 kg/m2 (95% CI 26.1 to 26.4). Parity was 95.6%, 30% smoked, 61.3% exercised regularly and 18% were obese. 1,545 women with a serum progesterone level on cycle days 14 to -3 were presumed to be in the luteal phase. Of these, 63.3% of women had an ovulatory cycle (n = 978) and 37% (n = 567) were anovulatory. Women with/ without ovulation did not differ in age, BMI, cycle day, menarche age, cigarette use, physical activity, % obesity or self-reported health. There were minimal differences in parity (96.7% vs. 94.5%, P = 0.04) and major differences in progesterone level (24.5 vs. 3.8 nmol/L, P = 0.001).ConclusionAnovulation in a random population occurs in over a third of clinically normal menstrual cycles.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26291617 · DOI · PMC4546331

Modulation of the Inflammatory Response in Polycystic Ovary Syndrome (PCOS)-Searching for Epigenetic Factors [3]

Review article Szukiewicz D, Trojanowski S, Kociszewska A, Szewczyk G · · 2022 · cited 51 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age.
Closing excerpt
Epigenetic modulation of androgenic activity in response to inflammatory signaling is also discussed.
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 (213 words)

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. Despite its incidence, the syndrome is poorly understood and remains underdiagnosed, and female patients are diagnosed with a delay. The heterogenous nature of this complex disorder results from the combined occurrence of genetic, environmental, endocrine, and behavioral factors. Primary clinical manifestations of PCOS are derived from the excess of androgens (anovulation, polycystic ovary morphology, lack of or scanty, irregular menstrual periods, acne and hirsutism), whereas the secondary manifestations include multiple metabolic, cardiovascular, and psychological disorders. Dietary and lifestyle factors play important roles in the development and course of PCOS, which suggests strong epigenetic and environmental influences. Many studies have shown a strong association between PCOS and chronic, low-grade inflammation both in the ovarian tissue and throughout the body. In the vast majority of PCOS patients, elevated values of inflammatory markers or their gene markers have been reported. Development of the vicious cycle of the chronic inflammatory state in PCOS is additionally stimulated by hyperinsulinemia and obesity. Changes in DNA methylation, histone acetylation and noncoding RNA levels are presented in this review in the context of oxidative stress, reactive oxygen species, and inflammatory signaling in PCOS. Epigenetic modulation of androgenic activity in response to inflammatory signaling is also discussed.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 36498989 · DOI · PMC9736994

The Leucine-mTOR-Autophagy Axis in Granulosa Cells Mediates Circadian Disruption-Induced Anovulation [4]

Research article He R, Mo J, Lin Z, Zhu K, Wang Y, Yu J, et al. · · 2026 · cited 1 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
Background: Ovulation disorders represent the most common cause of infertility in women.
Closing excerpt
The potential therapeutic targeting of leucine-mTOR pathways for managing PCOS should be investigated.
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 (266 words)

Background: Ovulation disorders represent the most common cause of infertility in women. Previous studies have reported that continuous light exposure can induce anovulation. However, the underlying mechanisms remain unclear. Methods: We assessed the phenotypes of ovulation disorders by using vaginal smears, hormone levels, and ovarian morphology. Metabolomics and RNA sequencing were employed to identify key metabolites and explore potential underlying mechanisms. Additionally, we investigated the effects of a leucine-rich diet on the phenotypes of ovulation disorders and autophagy. Serum levels of branched-chain amino acids (BCAAs) in patients with polycystic ovary syndrome (PCOS) were also measured. Causality was explored by using Mendelian randomization (MR) methods based on GWAS summary data. Results: Female SD rats subjected to continuous light exhibited disrupted estrous cycles and polycystic ovaries, as well as increased anti-Müllerian hormone (AMH) levels. Metabolic profiling revealed that leucine was a pivotal metabolite. Specifically, a high-leucine diet induced anovulation and polycystic morphology, along with reducing autophagy, in rats under normal light conditions; additionally, leucine restriction alleviated these effects in recovered rats. Moreover, the mTOR-ULK1-LC3-II/I autophagy pathway was influenced both in vivo and in vitro by leucine. In patients with PCOS, elevated serum BCAA levels (especially leucine) were observed to be correlated with increased AMH levels, higher luteinizing hormone (LH)-to-follicle-stimulating hormone (FSH) ratios, and higher antral follicle counts. MR analysis indicated that night shift work may increase the risk of PCOS through elevated serum leucine levels. Conclusions: These results suggest that the disruption of the leucine-mTOR-autophagy axis in granulosa cells (GCs) mediates continuous light-induced ovulation disorders. The potential therapeutic targeting of leucine-mTOR pathways for managing PCOS should be investigated.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41362744 · DOI · PMC12681872

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 Follicle dynamics and anovulation in polycystic ovary syndrome [5]
    Franks S, Stark J, Hardy K · Hum Reprod Update · 2008 · cited 446 times (Europe PMC)
  • Research article The management of anovulatory infertility in women with polycystic ovary syndrome: an analysis of the evidence to support the development of global WHO guidance [6]
    Balen AH, Morley LC, Misso M, Franks S, Legro RS, Wijeyaratne CN, et al. · Hum Reprod Update · 2016 · cited 441 times (Europe PMC)
  • Research article Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility [7]
    Morley LC, Tang T, Yasmin E, Norman RJ, Balen AH · Cochrane Database Syst Rev · 2017 · cited 164 times (Europe PMC)
  • Research article Physiological classification of anovulatory conditions in cattle [8]
    Wiltbank MC, Gümen A, Sartori R · Theriogenology · 2002 · cited 159 times (Europe PMC)
  • Research article Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility [9]
    Tang T, Lord JM, Norman RJ, Yasmin E, Balen AH · Cochrane Database Syst Rev · 2012 · cited 134 times (Europe PMC)
  • Research article Follicular dynamics in the polycystic ovary syndrome [10]
    Franks S, Mason H, Willis D · Mol Cell Endocrinol · 2000 · cited 131 times (Europe PMC)

References

  1. Li C, Xing C, Zhang J, Zhao H, Shi W, He B. Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome. . 2021. PMID 33849562 · DOI · PMC8045367
  2. Prior JC, Naess M, Langhammer A, Forsmo S. Ovulation Prevalence in Women with Spontaneous Normal-Length Menstrual Cycles - A Population-Based Cohort from HUNT3, Norway. . 2015. PMID 26291617 · DOI · PMC4546331
  3. Szukiewicz D, Trojanowski S, Kociszewska A, Szewczyk G. Modulation of the Inflammatory Response in Polycystic Ovary Syndrome (PCOS)-Searching for Epigenetic Factors. . 2022. PMID 36498989 · DOI · PMC9736994
  4. He R, Mo J, Lin Z, Zhu K, Wang Y, Yu J, et al.. The Leucine-mTOR-Autophagy Axis in Granulosa Cells Mediates Circadian Disruption-Induced Anovulation. . 2026. PMID 41362744 · DOI · PMC12681872
  5. Franks S, Stark J, Hardy K. Follicle dynamics and anovulation in polycystic ovary syndrome. Hum Reprod Update. 2008. PMID 18499708 · DOI
  6. Balen AH, Morley LC, Misso M, Franks S, Legro RS, Wijeyaratne CN, et al.. The management of anovulatory infertility in women with polycystic ovary syndrome: an analysis of the evidence to support the development of global WHO guidance. Hum Reprod Update. 2016. PMID 27511809 · DOI
  7. Morley LC, Tang T, Yasmin E, Norman RJ, Balen AH. Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility. Cochrane Database Syst Rev. 2017. PMID 29183107 · DOI · PMC6486196
  8. Wiltbank MC, Gümen A, Sartori R. Physiological classification of anovulatory conditions in cattle. Theriogenology. 2002. PMID 11775971 · DOI
  9. Tang T, Lord JM, Norman RJ, Yasmin E, Balen AH. Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility. Cochrane Database Syst Rev. 2012. PMID 22592687 · DOI
  10. Franks S, Mason H, Willis D. Follicular dynamics in the polycystic ovary syndrome. Mol Cell Endocrinol. 2000. PMID 10963873 · 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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At a glance

2,352
PubMed records on this heading
6%
published since 2020
429
review articles
125
randomized trials
10
verified references below

Counts come from PubMed on 2026-10-31; they show how much has been written, not how strong the evidence is.

Related topics See all →

  • Polycystic Ovary SyndromeCancer and Oncology
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