Fertility Blog

Male Factor Redefined

by Dr. Susan Daniel

The World Health Organization (WHO) has recently published the results of a large study aimed at developing better reference values for human semen analyses which involved men from eight countries on three different continents. Previous to this study, the accepted “normal” or “reference” values for semen parameters had been derived from poorly defined populations and conducted using methods that may not have been standardized between laboratories.

The following table compares the old (WHO IV) reference values with the new (WHO V).

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What does this mean for patients? The semen analysis is an important test and often the only test used for the diagnosis of male factor infertility. Using the old reference values of WHO IV, ICSI (intracytoplasmic sperm injection) was generally recommended when sperm morphology was less than 15% normal forms. With the new reference values of WHO V, ICSI is recommended when morphology falls below 4%. When morphology is 4% or greater, oocytes are inseminated with 50,000-100,000 motile sperm by routine IVF. The fertilization and pregnancy rates have not changed even with less ICSI.

NB Morphology is no the only measurement used to diagnose male factor infertility. Each semen analysis is assessed individually along with the medical history to determine the most appropriate course of treatment.

Cooper, T.G., Noonan, E., von Eckardstein, S., Auger, J., Baker, H.W.G., Behre, H.M. Haugen, T.B., Kruger, T, Wang, C., Mbizvo, M.T., and Vogelsong, K.M. (2010). World Health Organization reference values for human semen characteristics. Human Reprodroduction Update, 16(3): 231-45.