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

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 5th centile values for concentration, motility and morphology are: 16 × 106/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.

Do environmental and occupational exposure to pyrethroids and organophosphates affect human semen parameters? Results of a systematic review and meta‐analysis

“…Comparing our results with the last WHO manual on semen analysis (Campbell et al, 2021) Padungtod et al, 2000), one for sperm morphology (Multigner et al, 2008) and two for sperm viability (Multigner et al, 2008;Yucra et al, 2006).…”

The Sixth Edition of the WHO Manual for Human Semen Analysis: A Critical Review and SWOT Analysis

“…The 6th Edition also aimed to address the drawback of the 5th Edition related to the demographic under-representation of some geographical regions. Hence, the new 6th Edition combined data of the previous 5th Edition and additional new data of fertile men, whose partners had a time to pregnancy ≤12 months, collected between 2010 and 2020 [18]. Thus, the 6th Edition contains results of semen samples of 3589 fertile men (1800 subjects from the 5th Edition and 1789 new subjects).…”

Necrozoospermia: The tree that hides the forest

“…Sperm vitality is defined by the proportion of living spermatozoa in the ejaculate and according to WHO, its assessment is of particular relevance in cases of poor motility (less than 40% of total sperm motility) as the presence of a large proportion of live, but immotile spermatozoa can indicate structural defects in the flagellum 2 . Based on the distribution of semen parameters in a population of fertile men, Campbell et al 3 . determined the 5th percentile value for sperm vitality to be 54% (95% CI = 50%–56%) which does not constitute an established threshold for necrozoospermia.…”