Comments on the release of the 5th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen

Abstract

The authors of the World Health Organization Semen Analysis Manual are to be congratulated on producing a new edition; it is an essential tool to disseminate good practice in andrology. However, the tests described have poor prognostic power to predict a man's fertility and show little about the underlying causes of sub-fertility. This commentary urges a revival of research into the diagnosis of male fertility. It suggests that fertility should be regarded as a continuum and that the artificial binary division between fertile and infertile should be abandoned. Models to predict a sub-fertile couple's chance of conception in a year should be developed on the basis of prospective data. These models would allow for sophisticated decision making about management. The future lies in the identification of tests to detect underlying pathologies open to specific treatment. Leads such as oxidative stress, defects in the intracellular regulation and the developing field of proteomics should be explored.

Figure 1

The probability (with 95% confidence intervals) of in vitro fertilization (IVF) success declines only minimally with the concentration of normal motile spermatozoa in semen. Data are from 986 consecutive first cycles of IVF in which at least six eggs were available for fertilization at the University of Bristol Centre for Reproductive Medicine before the introduction of intra-cytoplasmic sperm injection (ICSI). Obtaining four embryos is a good surrogate variable for live birth because the chance of success declines rapidly if < 4 embryos are available, but improves relatively more slowly if there are more embryos.