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 (1,106 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
An accumulation of PUS in the uterine cavity (uterus). Pyometra generally indicates the presence of infections.
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: Pyometras.
Where it fits in the MeSH classification
- Broader topics
- Uterine Diseases
Related concepts
Research landscape
PubMed indexes 427 records tagged with the MeSH heading “Pyometra” (counts retrieved 2026-11-04). 162 of them (37.9%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 203 records.
Reviews account for 23 records (5.4%) and meta-analyses for 1. Randomized controlled trials number 3 (0.7%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 38 |
| 2000-2009 | 24 |
| 2010-2019 | 203 |
| 2020 onward | 162 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 23 | 5.4% |
| Meta-analyses | 1 | 0.2% |
| Randomized controlled trials | 3 | 0.7% |
Method: PubMed query "Pyometra"[MeSH Terms] with publication-type and date filters, retrieved 2026-11-04.
Reading the evidence in kidney, urology and women's health
Kidney, urinary and reproductive health research uses lab markers (such as creatinine), imaging, symptom scores and registry data on pregnancy and birth. Findings about pregnancy are especially sensitive to who was studied and when in pregnancy exposure occurred. Nothing on this page is advice about treatment, fertility or pregnancy; speak to a qualified clinician. Check the population, the outcome measured and whether the study accounted for other health differences between groups.
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 |
|---|---|---|---|---|
| Outcome of pyometra in female dogs and predictors of peritonitis and prolonged postoperative hospitalization in surgically treated cases | 2014 | Research article Design not recorded in structured metadata | 43 | cc by PMID 24393406 · DOI · PMC3892096 |
| Blood lactate levels in 31 female dogs with pyometra | 2009 | Research article Design not recorded in structured metadata | 25 | cc by PMID 19134167 · DOI · PMC2630309 |
| Closed cervix is associated with more severe illness in dogs with pyometra | 2017 | Research article Design not recorded in structured metadata | 23 | cc by PMID 28056957 · DOI · PMC5217653 |
| Multidrug resistance of bacterial pathogens in canine pyometra | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 41834532 · DOI · PMC13327223 |
Outcome of pyometra in female dogs and predictors of peritonitis and prolonged postoperative hospitalization in surgically treated cases [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundOne of the most common diseases in intact bitches is pyometra--a potentially life-threatening disease associated with a variety of clinical and laboratory findings.
- Closing excerpt
- The results of the present study may be valuable for identifying peritonitis and predicting increased morbidity in surgically treated bitches with pyometra.
- 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 (275 words)
BackgroundOne of the most common diseases in intact bitches is pyometra--a potentially life-threatening disease associated with a variety of clinical and laboratory findings. The aims of the present study were to describe complications of the disease and to investigate clinically useful indicators associated with peritonitis and/or prolonged postoperative hospitalization.ResultsA retrospective study was performed using records from 356 bitches diagnosed with pyometra during the years 2006-2007 at the University Animal Hospital, Swedish University of Agricultural Sciences, Uppsala, Sweden. Of the 356 bitches, 315 were surgically treated by ovariohysterectomy, 9 were medically treated and 32 were euthanized without treatment. In the surgically treated bitches, univariable associations between clinical and laboratory data, risk for prolonged hospitalization (≥ 3 days) and/or signs of peritonitis, were analyzed by Chi-square and Fisher's exact test. Logistic regression models were used to assess multivariable associations.The most common complication observed in surgically treated bitches was peritonitis (40 bitches), followed by urinary tract infection (19 bitches), wound infection (8 bitches), uveitis (6 bitches), and cardiac arrhythmia (5 bitches). Leucopenia and fever/hypothermia were associated with increased risk for peritonitis (18-fold and three-fold, respectively). Moderate to severe depression of the general condition, pale mucous membranes and leucopenia were associated with increased risk (seven-fold, three-fold, and over three-point-five-fold, respectively) for prolonged postoperative hospitalization.ConclusionsSeveral clinically useful indicators were identified. Leucopenia was the most important marker, associated with 18-fold increased risk for peritonitis and an over three-point-five increased risk for prolonged hospitalization. Fever/hypothermia, depression and pale mucous membranes were associated with increased risk for peritonitis and/or prolonged hospitalization. The results of the present study may be valuable for identifying peritonitis and predicting increased morbidity in surgically treated bitches with pyometra.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 24393406 · DOI · PMC3892096
Blood lactate levels in 31 female dogs with pyometra [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundCanine pyometra is a life-threatening disease common in countries where spaying of dogs is not routinely performed.
- Closing excerpt
- The value of a single and repeated lactate analysis in more severely affected cases remains to be determined.
- 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 (327 words)
BackgroundCanine pyometra is a life-threatening disease common in countries where spaying of dogs is not routinely performed. The disease is associated with endotoxemia, sepsis, systemic inflammatory response syndrome (SIRS) and a 3-4% mortality rate. Blood lactate analysis is clinically valuable in predicting prognosis and survival, evaluating tissue perfusion and treatment response in human and veterinary critical care settings. The aims of the present study were to investigate 1) the blood lactate levels of female dogs with pyometra by a hand-held analyser and 2) if these levels are related with the clinical status or other biochemical or hematological disorders.MethodsIn total 31 female dogs with pyometra admitted for surgical ovariohysterectomy and 16 healthy female control dogs were included in the present study. A complete physical examination including SIRS-status determination was performed. Blood samples for lactate concentrations, hematological and biochemical parameters, acid-base and blood gas analysis and other laboratory parameters were collected and subsequently analysed. The diagnosis pyometra was verified with histopathological examination of the uterus and ovaries. Increased hospitalisation length and presence of SIRS were used as indicators of outcome.ResultsIn the pyometra group the median blood lactate level was 1.6 mmol l(-1) (range 2.5 mmol l(-1)) was demonstrated in one female dog with pyometra (3%), and was not associated with longer hospitalisation or presence of SIRS. Lactate measurement was not indicative of peritonitis. None of the bitches died during or within two months of the hospital stay. The measurements of temperature, heart rate, respiratory rate, percentage bandforms of neutrophilic granulocytes, alpha2-globulins, creatinin, pvCO2, TCO2 and base excess showed significant differences between the SIRS positive and the SIRS negative pyometra cases.ConclusionIncreased blood lactate concentrations were demonstrated in 3% (1/31), and SIRS was present in 61% (19/31) of the female dogs with pyometra. Preoperative lactate levels were not related with presence of SIRS or prolonged hospitalisation. Lactate measurement was not indicative of peritonitis. The value of a single and repeated lactate analysis in more severely affected cases remains to be determined.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 19134167 · DOI · PMC2630309
Closed cervix is associated with more severe illness in dogs with pyometra [3]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundPyometra, a life-threatening bacterial infection of the uterus, is classified as open or closed depending on the functional patency of the cervix i.
- Closing excerpt
- These findings may be clinically valuable for optimizing monitoring and treatments in dogs with the disease.
- 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 (206 words)
BackgroundPyometra, a life-threatening bacterial infection of the uterus, is classified as open or closed depending on the functional patency of the cervix i.e. presence or absence of vaginal discharge. In closed cervix pyometra, pus and bacterial products accumulate in the uterus, which is thought to induce a more severe illness. The aim of this study was to investigate whether disease severity or outcome differed in dogs with open or closed cervix pyometra.ResultsProspectively collected data from 111 female dogs diagnosed with pyometra at the University Animal Hospital, Swedish University of Agricultural Sciences, Uppsala, intermittently during 2005-2012 was analyzed. Seventy-two dogs (65%) had open cervix, whereas 39 dogs (35%) had closed cervix. Differences between the two groups were explored by Wilcoxon Two Sample Test for continuous variables and Chi-square or Fisher's exact test for categorical variables. P ConclusionsIn dogs with closed cervix, sepsis was more common, the general physical condition more often moderately to severely depressed and leukocytosis, neutrophilia and monocytosis more frequently found. The results showed that closed cervix was associated with a more severe illness than open cervix at admission but not with poorer outcome as measured by postoperative hospitalization. These findings may be clinically valuable for optimizing monitoring and treatments in dogs with the disease.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 28056957 · DOI · PMC5217653
Multidrug resistance of bacterial pathogens in canine pyometra [4]
Abstract reading summary — source excerpts
- Opening excerpt
- ObjectivesTo characterise multidrug antimicrobial resistance and pathogenicity profiles of bacteria isolated from different anatomical sites in bitches with pyometra, emphasising their clinical relevance for diagnosis and therapeutic decision-making in small animal practice.
- Closing excerpt
- Furthermore, the recovery of genetically related Escherichia coli isolates from intestinal and reproductive tract samples supports the intestinal microbiota as a relevant source of infection in affected bitches.
- 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 (298 words)
ObjectivesTo characterise multidrug antimicrobial resistance and pathogenicity profiles of bacteria isolated from different anatomical sites in bitches with pyometra, emphasising their clinical relevance for diagnosis and therapeutic decision-making in small animal practice.Materials and methodsBacteria were obtained from the faeces, urine, uterus and vagina of 23 dogs diagnosed with pyometra undergoing ovariohysterectomy. Antimicrobial resistance profiles were analysed for all identified isolates, together with phylogenetic classification of Escherichia coli and detection of virulence factor-encoding genes.ResultsBacterial isolates obtained from faecal, urinary, uterine and vaginal samples showed predominantly positive growth for Escherichia coli, followed by Staphylococcus spp., Klebsiella pneumoniae and Proteus spp. Among these isolates recovered from each anatomical site, multidrug-resistant bacteria - defined as resistance to three or more classes of antimicrobials - were identified across all bacterial genera, with frequencies of 37.7% among faecal isolates, 16.7% among urinary isolates, 44.5% among uterine isolates and 100% among vaginal isolates, except for Enterobacter spp. Among dogs positive for Escherichia coli (11/23), phylogroups A/C (30.9%) were the most prevalent, followed by D/E (16.9%), B2 (15.5%), B1 (12.7%), A (12.7%), C (8.5%) and U (2.8%). In 90% (10/11) of cases, Escherichia coli isolates recovered from faecal, vaginal and/or uterine samples belonged to the same clonal family, suggesting faecal contamination. Overall, 77.4% of Escherichia coli isolates of uterine origin were classified as resistant or multidrug-resistant, and 83.9% harboured one or more virulence factor-encoding genes (hlyA, uspA, papC and predominantly fimH). Phylogroup B2 was the only group in which all assessed virulence factors were simultaneously detected.Clinical significanceThe presence of multidrug-resistant bacteria across all genera isolated in cases of canine pyometra underscores the clinical importance of antimicrobial susceptibility testing. Furthermore, the recovery of genetically related Escherichia coli isolates from intestinal and reproductive tract samples supports the intestinal microbiota as a relevant source of infection in affected bitches.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41834532 · DOI · PMC13327223
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 Pyometra in Small Animals [5]
- Research article Medical treatment for pyometra in dogs [6]
- Research article Canine pyometra: What is new? [7]
- Research article Pyometra in Small Animals 2.0 [8]
- Research article Clinical and molecular characteristics of pyometra in female dogs [9]
- Research article Pyometra in the queen: To spay or not to spay? [10]
References
- Jitpean S, Ström-Holst B, Emanuelson U, Höglund OV, Pettersson A, Alneryd-Bull C, et al.. Outcome of pyometra in female dogs and predictors of peritonitis and prolonged postoperative hospitalization in surgically treated cases. . 2014. PMID 24393406 · DOI · PMC3892096
- Hagman R, Reezigt BJ, Bergström Ledin H, Karlstam E. Blood lactate levels in 31 female dogs with pyometra. . 2009. PMID 19134167 · DOI · PMC2630309
- Jitpean S, Ambrosen A, Emanuelson U, Hagman R. Closed cervix is associated with more severe illness in dogs with pyometra. . 2017. PMID 28056957 · DOI · PMC5217653
- Camozzi MGM, Waller SB, Castelhano EC, Neves ALS, Arrais BR, Pinto JFN, et al.. Multidrug resistance of bacterial pathogens in canine pyometra. . 2026. PMID 41834532 · DOI · PMC13327223
- Hagman R. Pyometra in Small Animals. Vet Clin North Am Small Anim Pract. 2018. PMID 29933767 · DOI
- Fieni F, Topie E, Gogny A. Medical treatment for pyometra in dogs. Reprod Domest Anim. 2014. PMID 24947858 · DOI
- Hagman R. Canine pyometra: What is new?. Reprod Domest Anim. 2017. PMID 27807901 · DOI
- Hagman R. Pyometra in Small Animals 2.0. Vet Clin North Am Small Anim Pract. 2022. PMID 35465903 · DOI
- Hagman R. Clinical and molecular characteristics of pyometra in female dogs. Reprod Domest Anim. 2012. PMID 23279529 · DOI
- Hollinshead F, Krekeler N. Pyometra in the queen: To spay or not to spay?. J Feline Med Surg. 2016. PMID 26733546 · DOI · PMC11148877
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 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
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Evidence strength
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