Impact of the New WHO Guidelines on Diagnosis and Practice of Male Infertility

The World Health Organization (WHO) has established new reference values for semen characteristics in its 5th edition manual which are lower than those previously reported. Several questions arise after a careful examination of the proposed new values, especially regarding the implications of these references for diagnosis and treatment of male infertility. Despite the notable advance of using controlled studies involving couples whose time to pregnancy was less than 12 months to generate the new limits, reference studies are limited with regard to the population analyzed and the methods used for semen evaluation. As such, it seems unreasonable to assume that reference values represent global semen characteristics of fertile men as proposed in the 5 edition WHO manual. Caution should be exercised to not overinterpret the new reference values as they may fail to accurately discriminate populations of fertile and infertile men. Properly performed semen analyses coupled with an adequate examination of the man can give valuable information related to the organs producing “semen”, a highly complex fluid, and thus help in better understanding of the physiology of the reproductive organs and the causes of their dysfunctions. The present commentary discusses concerns related to the publication of the new reference values for semen parameters such as the impact on patient referral, diagnosis, treatment of recognized conditions such as varicocele and indications of assisted reproductive modalities. We conclude that more debate is needed before the adoption of the proposed WHO current reference values by andrology laboratories around the world. For those considering to adopt them, a better approach would be the presentation of reference values by percentiles rather than solely the lower cutoff limits. The time has come for technological developments that bring robust and costeffective clinically useful sperm function tests to replace, at least partially, the shortcomings of routine semen analysis.