New WHO guidelines for semen analysis to be reviewed during Plenary Session
The World Health Organization published its latest guidelines for semen analysis in April 2010. The new guidelines are part of the WHO Laboratory Manual for the Examination and Processing of Human Semen, 5th ed., and represent a major change over the prior guidelines published in 1999.
“The previous references were based on a combination of expert opinion and consensus,” explained Stanton C. Honig, M.D., Associate Clinical Professor of Urology at the University of Connecticut Health Center in Farmington. “They were not based on any specific data. The new guidelines are based on semen analysis from multiple countries, multiple continents and multiple studies of fathers who have gotten their partners pregnant within 12 months.”
Dr. Honig will moderate a point-counterpoint presentation on the new guidelines from 10:00 – 10:20 a.m. during this morning’s Plenary Session in Hall D of the Walter E. Washington Convention Center. The session is titled Semen Analysis – Is There a Definable Normal Range?
Mark Sigman, M.D., Chief of Urology at Rhode Island Hospital and The Miriam Hospital, and also Chief of Urology at the Warren Alpert Medical School of Brown University in Providence, Rhode Island, will discuss the importance of numbers as well as the limitations inherent in the new guidelines.
Dr. Honig noted that the new guidelines offer evidence-based reference ranges and reference limits for the fertile population, but are tricky to interpret for those who are infertile. There are no absolute values when it comes to semen analysis and pregnancy, and the new ranges can easily be misinterpreted if the basis of how they were reached is not fully understood.
“These guidelines have defined the broad parameters of the men who did get their partners pregnant,” Dr. Honig said. “There is a lot of overlap between couples who are fertile and couples who are infertile. You could have someone with low sperm numbers who got their partner pregnant at 12 months and you could have someone else who has high sperm numbers but didn’t get his partner pregnant until the 13th month.”
One of the major improvements the guidelines make has to do with breaking semen parameters into percentiles. However, it’s easy to misinterpret percentiles for absolute cutoff values, Dr. Honig noted, which is not an appropriate use of individual patient data or the guidelines.
“The guidelines are saying that 95 percent of the people who got pregnant were above that particular value, i.e. 15 million sperm/cc and 32 percent motility,” Dr. Honig explained. “It’s not a cutoff value, but it gives you a sense of what the numbers mean on a broad basis.”
Dolores Lamb, Ph.D., Professor of Urology, and Molecular and Cellular Biology, and Director of the Laboratory for Male Reproductive Research and Testing at Baylor College of Medicine in Houston, Texas, will address a second key issue: semen numbers are a beginning, not a final conclusion. While an individual’s semen count matters, there are multiple factors that can affect a successful pregnancy. Health matters, sperm motility matters and the volume of ejaculate matters. There are other situations when the quality of the sperm can be more important than the quantity of sperm.
“We will also be talking about function tests of the sperm, looking at things like reactive oxygen species and DNA fragmentation and application of clinical proteomics, the protein evaluation of the sperm,” Dr. Honig said.