Men and numbers, what a relationship! After my talk on male infertility at the Fertility Planit Show this weekend, I was struck by the numbers of questions asked about the semen analysis. Although very important to me, interest in the other 3 components of the male infertility evaluation, the personal history, physical exam and hormone findings, were all trumped by the sperm count. What do the numbers on a semen analysis really mean?
Speaking in Context
The semen analysis should be read in context of the individual. Within this framework, this is what comes to mind:
- Ejaculation is a biologic process, kind of like a sneeze, that was never meant to be analyzed, counted, or ordered. But, we do it anyway.
- There is great daily, weekly and seasonal variability in the results.
- In and of itself, except when zero, the semen analysis is not a great measure of actual fertility.
Breaking It Down
Here is my loosely structured, high-level view of each of the 4 main variables typically found on a semen analysis.
- Volume. This is total amount of fluid in the sample. It arises from 3 sources and varies widely with ejaculation frequency. However, when it is low (below 1.5-2mL) you can hang your hat that something is up. The causes of low ejaculate volume are: collection error, retrograde ejaculation, missing vas deferens, ejaculatory duct obstruction or low testosterone.
- Sperm Count. This is really a “concentration” of sperm number per unit of fluid. When it is high, I typically don’t worry about it. But when it is low, I do. To me, the sperm count is the closest thing we have to a “biomarker” of a man’s overall health as it is influenced by lifestyle issues (alcohol, hot tubs, obesity, diet, disease, fevers, stress, medications, to name a few), findings on exam (varicocele, epididymitis, blockage) or genetic issues (Y-chromosome microdeletions, chromosome counts).
- Sperm Motility. This is the proportion of sperm that actually move in the sample. And remember, moving sperm do all of the work. Therefore, this variable has the strongest association with actual fertility. To me, sperm motility is a more sensitive indicator of insults to the body than is the sperm count. It also responds more rapidly to corrections than does the sperm count. The same issues that affect sperm count can also affect motility, but they affect motility at lower doses. Other conditions, such as antisperm antibodies or immotile cilia syndromes, only affect sperm motility.
- Morphology. This is an actuarial analysis of sperm shape. It is a tedious and time-consuming assessment of sperm anatomy that is said to reflect on their “fertilizability” at IVF. However, it is complex enough to make it difficult to standardize well across labs and even among individual technicians. In addition, sperm shape in general has nothing to do with the quality of its genetic payload. Therefore it has little to no clinical value in predicting a successful pregnancy at-home or with assisted reproduction. To me, a low sperm morphology suggests that the “factory” (testicle) is overheated or somehow impaired and that the product (sperm) that is made has crooked headlights or a bad paint job. As a doctor, it encourages me to focus more on issues with the individual and his “factory.”
So that’s my 30,000 foot view of the semen analysis. It’s not really the number of cards you hold as much as it is the quality of the cards and the person who holds them. Words of advice: you may in fact be “holding all of the cards” but they are being “lost in the shuffle.” The cards may not be “stacked against you” but you just need to “play your cards right.”