Year : 2016  |  Volume : 18  |  Issue : 2  |  Page : 163-170

Effect of varicocele on semen characteristics according to the new 2010 World Health Organization criteria: a systematic review and meta-analysis

1 American Center for Reproductive Medicine, Cleveland Clinic, 10681 Carnegie Avenue, X-11, Cleveland, OH 44195, USA
2 Department of Health Services, Saint Joseph's University, Post Hall 111, Philadelphia, PA, USA
3 Fertility and IVF Unit, Soroka University Medical Center, Ben-Gurion University of the Negev, Beersheba, Israel
4 ANDROFERT, Center for Male Reproduction, Av. Dr. Heitor Penteado, 1464, Campinas, SP 13075-460, Brazil

Correspondence Address:
Prof. Ashok Agarwal
American Center for Reproductive Medicine, Cleveland Clinic, 10681 Carnegie Avenue, X-11, Cleveland, OH 44195
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1008-682X.172638

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This study investigated the effects of varicocele on semen parameters in infertile men based on the new 2010 World Health Organization laboratory manual for the examination of human semen. Semen analysis results (volume, sperm count, motility, and morphology) were the primary outcomes. An electronic search to collect the data was conducted using the Medline/PubMed, SJU discover, and Google Scholar databases. We searched articles published from 2010 to August 2015, i.e., after the publication of the 2010 WHO manual. We included only those studies that reported the actual semen parameters of adult infertile men diagnosed with clinical varicocele and contained a control group of either fertile men or normozoospermic men who were not diagnosed with varicocele. Ten studies were included in the meta-analysis, involving 1232 men. Varicocele was associated with reduced sperm count (mean difference: −44.48 × 10 [6] ml−1 ; 95% CI: −61.45, −27.51 × 10 [6] ml−1 ; P < 0.001), motility (mean difference: −26.67%; 95% CI: −34.27, −19.08; P < 0.001), and morphology (mean difference: −19.68%; 95% CI: −29.28, −10.07; P < 0.001) but not semen volume (mean difference: −0.23 ml; 95% CI: −0.64, 0.17). Subgroup analyses indicated that the magnitude of effect was influenced by control subtype but not WHO laboratory manual edition used for semen assessment. We conclude that varicocele is a significant risk factor that negatively affects semen quality, but the observed pooled effect size on semen parameters does not seem to be affected by the WHO laboratory manual edition. Given most of the studies published after 2010 still utilized the 1999 manual for semen analysis, further research is required to fully understand the clinical implication of the 2010 WHO laboratory manual on the association between varicocele and semen parameters.

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