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Cited by 112Sperm and Testicular FunctionMale Reproductive Health StudiesUrologic and reproductive health conditions

Distribution of semen examination results 2020 – A follow up of data collated for the WHO semen analysis manual 2010

Open access
Campbell, Martin J., Lotti, Francesco, Baldi, Elisabetta, Schlatt, Stefan, Festin, Mario P. R., Björndahl, Lars, Toskin, Igor, Barratt, Christopher L. R.·2021·Andrology
DOI 10.1111/andr.12983
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Abstract

Background: It is now 11 years since publication of the WHO 2010 guidelines for semen assessment values, and it is critical to determine whether they are still valid and/or whether they should be modified. Objectives: To utilise data published since 2010 and combine these with data used in the 2010 assessment to provide an updated and more comprehensive representation of the fertile man. This may be utilised to present an updated distribution of values for use by WHO in 2021. Materials and Methods: Two specific analyses were performed namely, (1) Analysis 1: Examination of published data following publication of WHO 2010 [termed 2010–2020 data]. (2) Analysis 2: Examination of the data used to help formulate the 2010 distribution of values combined with the data from Analysis (1) [termed WHO 2020]. Results: In total, data from more than 3500 subjects, from twelve countries and five continents were analysed. The 5 th centile values for concentration, motility and morphology are: 16 × 10 6/ml, 30% progressive motility [42% total motility] and 4% normal forms. Discussion: This study presents substantial additional information to establish more comprehensive and globally applicable lower reference values for semen parameters for fertile men although they do not represent distinct limits between fertile and subfertile men. There are still data missing from many countries and, some geographical regions are not represented. Moreover, the number of subjects although significant is still relatively low (<4000). Conclusion: These distributions of values now include semen analysis providing a more global representation of the fertile man. Increasing the number of subjects provides robust information that is also more geographically representative.

AI snapshot

Written from the paper’s full text.

TL;DR

This follow-up combined published post-2010 semen data from fertile men with data used for the WHO 2010 reference values to update distributions. The updated 5th centiles were similar to WHO 2010: 16 × 10⁶/ml sperm concentration, 30% progressive motility [42% total motility], and 4% normal forms.

Key findings

  • Analysis 1 (2010–2020 data) included up to 1789 subjects from Africa, Asia, and Europe; 5th centiles were 18 × 10⁶/ml for concentration (95% CI 15–20), 27% progressive motility (95% CI 26–30) [43% total motility, 95% CI 40–45], and 4% normal forms (95% CI 3.1–4.0).
  • Analysis 2 (WHO 2020) combined data for up to 3589 subjects from twelve countries and five continents; 5th centiles were 16 × 10⁶/ml for concentration (95% CI 15–18), 30% progressive motility (95% CI 29–31) [42% total motility, 95% CI 40–43], and 4% normal forms (95% CI 3.9–4.0).
  • For comparison, WHO 2010 5th centiles were 15 × 10⁶/ml, 32% progressive motility [40% total motility], and 4% normal forms; the authors state the 5th centiles are not noticeably different and appear relatively robust.
  • The authors note the 16 × 10⁶/ml 5th centile is reasonably consistent with historical studies, including MacLeod and Gold 1951 where 5% of 1000 fertile men had sperm concentrations less than 20 × 10⁶/ml, and Naghma-E-Rehan et al. where 7% of 1300 fertile men had less than 20 million/ml; they suggest the 5th centile for fertile men is realistically between 15–20 million/ml.

Methods

  • Two analyses were performed: Analysis 1 reviewed published data from 1 January 2010 to 30 April 2020 on fertile men who achieved natural pregnancy with known TTP ≤12 months and abstinence of 2–7 days; infertility clinic/fertility assessment patients were excluded. Data from five published studies were supplied after exclusions, yielding up to 1789 subjects; data were collated in Microsoft Excel and analyzed with SPSS v25.
  • Analysis 2 combined the dataset used to help formulate WHO 2010 values—obtained from the editorial team of the sixth edition of the WHO laboratory manual and filtered to confirmed TTP ≤12 months and abstinence 2–7 days—with Analysis 1 data, yielding up to 3589 subjects.
  • Only studies citing WHO 2010 methods and providing some detail of adherence were included; morphology data from Aboutorabi et al. were excluded as not compliant with WHO 2010, and vitality assessments were available only from selected studies. The combined data are freely available at https://doi.org/10.15132/10000163.

Limitations

  • The paper states that relatively few studies were identified from 2010 onwards; some were excluded because methods were not WHO-recommended (e.g., the LIFE Study posted samples and analyzed them the following day), 167 studies lacked key details such as TTP, and some data could not be obtained (e.g., Tang L-X et al. because the main author was deceased; Punab et al. because data were not released).
  • The paper states that data are still missing from many countries and some regions are not represented (e.g., South America); only one African country (Egypt) is included, which is unlikely to represent the whole continent, and the number of subjects, although significant, is still relatively low (<4000).
  • The paper states that the WHO 2010 dataset is not publicly available, there is no independent analysis of it, it is unclear exactly which studies/subjects were used by Cooper et al., sample sizes differ slightly, and there is no way to verify whether the data obtained differed from the original; vitality was not available in the editorial board data. The text also makes evident that not all information was available for each subject.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1111/andr.12983

Cites

26 of 26 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 23 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    In the WHO 2020 combined analysis, the 5th centile for progressive motility is 30% (42% total motility).

    “The 5 th centile values for concentration, motility and morphology are: 16 × 10 6 /ml, 30% progressive motility [42% total motility] and 4% normal forms.”
    • Also stated in: § 3 | Result s · plain
      “The 5 th centiles for concentration, motility and morphology are: 16 × 10 6 /ml, 30% progressive motility [42% total motility] and 4% normal forms.”
    Quote in the paperSubstantial claim
  • Findingown data

    In the WHO 2020 combined analysis, the 5th centile for normal forms is 4%.

    “The 5 th centile values for concentration, motility and morphology are: 16 × 10 6 /ml, 30% progressive motility [42% total motility] and 4% normal forms.”
    • Also stated in: § 3 | Result s · plain
      “The 5 th centiles for concentration, motility and morphology are: 16 × 10 6 /ml, 30% progressive motility [42% total motility] and 4% normal forms.”
    Quote in the paperSubstantial claim
  • Findingnone given

    The number of subjects, although significant, is still relatively low (<4000).

    “Moreover, the number of subjects although significant is still relatively low (<4000).”
    • Also stated in: § 4 | DISCUSS ION · plain
      “Lastly, the number of subjects, although significant, is still relatively low (<4000).”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    In 167 studies, key details such as TTP of the fertile cohort could not be determined.

    “In 167 studies, we could not determine key details e.g.TTP of the fertile cohort, as this was outwith the study design.”
    Quote in the paperNot a substantial claim
  • Findingcitation

    The 5th centiles in WHO 2020 are not noticeably different from those of WHO 2010.

    “The 5 th centiles are not noticeably different from those of WHO 2010 1 giving confidence that such values are relatively robust.”
    • Also stated in: § 4 | DISCUSS ION · plain
      “What is reassuring about the recent and combined analysis was that the 5 th centiles were similar to WHO 2010.1,2”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims. 13
  • Classified as probably not a substantial claim. 5

  • May combine two claims.

    Findingown data

    Since 2010, seven published studies were identified as potentially suitable for detailed assessment, and data was supplied from five published studies.

    “Since 2010, seven published studies have been identified as potentially suitable for detailed assessment.Data was kindly supplied from five published studies [4][5][6][7][8] (Table 1).”
    Quote in the paperSubstantial claim0 of 5 sources checked
    • cites [4]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [5]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [6]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [7]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [8]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    There are still data missing from many countries and some geographical regions are not represented.

    “There are still data missing from many countries and, some geographical regions are not represented.”
    • Also stated in: § 4 | DISCUSS ION · plain
      “Secondly, there are still data missing from many countries and, some geographical regions are not represented e.g.South America.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Some data could not be obtained, for example data from Tang L-X et al. was not available as the main author was deceased, and Punab et al. data was not released by the author.

    “Moreover, even where data was originally indicated as potentially appropriate some data could unfortunately not be obtained e.g.data from Tang L-X et al., 11 was not available as the main author was deceased, in the case of Punab et al. 12 data was not released by the author.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [11]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [12]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    The WHO 2020 combined dataset comprises up to 3589 subjects from five continents (Africa, Oceania, Americas, Asia and Europe).

    “This combined data set presents a total of up to 3589 subjects, and incorporates data from five continents Africa, Oceania, Americas, Asia and Europe.”
    • Also stated in: § 3 | Result s · plain
      “which resulted in up to 3589 subjects for analysis (Analysis 2: WHO 2020).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    The dataset used to formulate the WHO 2010 reference values is not publicly available.

    “Firstly, the dataset used to formulate the WHO 2010 reference values is not publicly available.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Relatively few studies were identified from 2010 onwards.

    “Firstly, it was surprising that relatively few studies were identified from 2010 onwards.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The distribution of semen assessment values now includes results from more than 3500 subjects, from twelve countries and five continents, providing a more global representation of the fertile man.

    “In summary, the distribution of semen assessment values now includes results from more than 3500 subjects, from twelve countries and five continents, providing a more global representation of the fertile man.”
    • Also stated in: § Abstract · plain
      “These distributions of values now include semen analysis providing a more global representation of the fertile man.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The Analysis 1 (2010-2020) dataset comprises up to 1789 subjects from three continents (Africa, Asia and Europe).

    “The new data set presents a total of up to 1789 subjects, and incorporates data from three continents Africa, Asia and Europe.”
    • Also stated in: § 3 | Result s · plain
      “up to 1789 subjects were analysed (Analysis 1: 2010-2020).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The 5th centiles were presented as the lower reference values in WHO 2010 and have been ubiquitously used in the literature and clinical practice.

    “The 5 th centiles were presented as the lower reference values 1,2 and, as expected, these have been ubiquitously used in the literature and clinical practice.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [1]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [2]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Increasing the number of subjects provides robust information that is also more geographically representative.

    “Increasing the number of subjects provides robust information that is also more geographically representative.”
    • Also stated in: § 4 | DISCUSS ION · plain
      “Increasing the number of subjects provides robust information that is also more geographically representative.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductcitation

    Some studies were excluded as the methods used were not those recommended by WHO, for example the LIFE Study where semen samples were posted and analysed the following day.

    “Additionally, some were excluded as the methods used were not those recommended by WHO e.g.'Semen Quality and Time-to-Pregnancy, the LIFE Study', 10 whereby semen samples were posted and analysed the following day.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    The 5th centiles in WHO 2010 are 15 × 10^6/ml for concentration, 32% progressive motility [40% total motility] and 4% normal forms.

    “For comparison the 5 th centiles in WHO 2010 1 are 15 × 10 6 /ml, 32% progressive motility [40% total motility] and 4% normal forms.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites WHO 2010 1

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductown data

    Five studies documented using WHO 2010 standards for assessment, but the morphology assessment by Aboutorabi et al. was not compliant with WHO 2010 and was excluded.

    “Five studies documented using WHO standards for assessment (WHO 2010) however the morphology assessment by Aboutorabi et al. 5 was not compliant with WHO 2010 and therefore has been excluded.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [5]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    There was no data from Africa or China in the WHO 2010 reference ranges.

    “Moreover, a more global representation is required as there was no data from, for example, Africa or China.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The methodologies described in the 5th edition of the WHO manual provided guidance on quality control and quality assurance.

    “The methodologies as described in the 5 th edition of the WHO 1 manual provided guidance on quality control and quality assurance.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites WHO 1

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    The data was edited to include only semen analysis results with a confirmed TTP ≤ 12 months and an abstinence range of 2 but no more than 7 days.

    “Moreover, we edited the data, where appropriate, to include only those semen analysis results with a confirmed TTP ≤ 12 months and an abstinence range of 2 but no more than 7 days”
    Quote in the paperSubstantial claim
16 of 16

  • The authors state this as an assumption.

    When semen analysis was performed according to the 5th edition of the WHO laboratory manual, compliance to these procedures was assumed.

    “When semen analysis was performed according to 5 th edition of WHO laboratory manual compliance to these procedures was assumed.”

  • The paper relies on this without support.

    The dataset obtained from the editorial team of the sixth edition of the WHO laboratory manual is sufficiently equivalent to the dataset used to formulate the WHO 2010 reference values for the combined analysis.

    “The dataset used to help formulate the WHO 2010 distribution of values was obtained from the editorial team of the sixth edition of the upcoming 'WHO laboratory manual for the examination and processing of human semen' .This data was examined and prepared to include only those semen analysis results with a confirmed TTP ≤ 12 months and a sexual abstinence range between 2 and 7 days.”
    “The distribution of values in this data set for 2010, when analysed from the data provided, are not exactly the same as reported by Cooper et al. 2 We can only speculate as to why this is so.”
2 of 2

Cites

Flagged first, then by citations

2 of the 28 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. WHO, 2010, WHO laboratory manual for the examination and processing of human semen

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Related

Authors
Campbell, M. J., Lotti, F., Baldi, E., Schlatt, S., Festin, M. P. R., Björndahl, L., Toskin, I., & Barratt, C. L. R.
Affiliations
  • University of Dundee (GB)
  • University of Florence (IT)
  • University Hospital Münster (DE)
  • Philippine General Hospital (PH)
  • Karolinska University Hospital (SE)
  • World Health Organization (CH)
Corresponding author
Barratt, Christopher L. R.
ORCID
Venue
Andrology
Publisher
Wiley
Published
2021-03-17
Volume
9
Issue
3
Pages
817-822
ISSN
  • 2047-2919 (ISSN-L)
  • 2047-2927
DOI
10.1111/andr.12983
OpenAlex
W3128222907
Semantic Scholar
ead990847b81987ea440b53baa7001f4df52b067
Cited by
112
References
28
Citations by year
2026: 9 · 2025: 14 · 2024: 23 · 2023: 33 · 2022: 23 · 2021: 10
FWCI
15.58
Type
journal article
Language
en
Open access
Licence
Locations
  • Andrology (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Discovery Research Portal (University of Dundee) (publishedVersion, cc-by)
  • Florence Research (University of Florence) (submittedVersion, other-oa)
  • Greater South Information System
Funders
  • World Health Organization
  • UNICEF
  • University of Dundee
  • NHS Education for Scotland
Topics
  • Health Sciences › Medicine › Reproductive Medicine › Sperm and Testicular Function
  • Health Sciences › Health Professions › General Health Professions › Male Reproductive Health Studies
  • Health Sciences › Medicine › Rheumatology › Urologic and reproductive health conditions
Keywords
semen analysis, reference values, male fertility, sperm motility, sperm morphology, sperm concentration, fertile men
MeSH terms
Follow-Up Studies, Humans, Male, Reference Values, World Health Organization, Semen Analysis

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