Sperm function tests and fertility.
Traditionally, the diagnosis of male infertility has depended upon a descriptive evaluation of human semen with emphasis on the number of spermatozoa that are present in the ejaculate, their motility and their morphology. The fundamental tenet underlying this approach is that male fertility can be defined by reference to a threshold concentration of motile, morphologically normal spermatozoa that must be exceeded in order to achieve conception. Many independent studies have demonstrated that this fundamental concept is flawed and, in reality, it is not so much the absolute number of spermatozoa that determines fertility, but their functional competence. In the light of this conclusion, a range of in vitro tests have been developed to monitor various aspects of sperm function including their potential for movement, cervical mucus penetration, capacitation, zona recognition, the acrosome reaction and sperm-oocyte fusion. Such functional assays have been found to predict the fertilizing capacity of human spermatozoa in vitro and in vivo with some accuracy. Recent developments in this field include the introduction of tests to assess the degree to which human spermatozoa have suffered oxidative stress as well as the integrity of their nuclear and mitochondrial DNA. Such assessments not only yield information on the fertilizing capacity of human spermatozoa but also their ability to support normal embryonic development.
One of the biggest concerns of couples involved in an infertility work up relates to the status of the male partner’s sperm evaluation. While the thorough evaluation of sperm and sperm function should be given high priority in any infertility evaluation, we have found from our web page interactions with patients that often times the couple are told very little related to test results in this area. Or, in other cases, we hear of couples being told about “high numbers” of “abnormal” sperm, or “low” numbers of “good” sperm with little additional information about what those results mean to their chances for conception. Other very concerned couples have sent us copies of original semen analysis reports, having been told of “problems”. On review, many of these reports have been printed with very out of date data related to what “normal” fertility test results should be in a fertile man. While there is no substitute for the evaluation of semen and sperm testing results by a highly trained and specialized professional, the truth is that many modern laboratories and even some very well qualified physicians have not kept totally abreast of our changing understanding of sperm function, and our new and evolving views of “fertile” sperm test results.
It is our opinion that sperm test results should not be presented to patients by way of a five minute telephone conversation. Instead, we feel each couple is entitled to sit in consultation with their physician or nurse or Laboratory Director and be advised of the specific results, and how those results compare to the results of known fertile males tested in that laboratory. Couples should also ask and be told about how the “Normal” ranges for the individual laboratory were established. There are, of course, many more things to be elicited from the laboratory, but we feel this to be a good starting point.