Re: How does sperm count vary with consecutive ejaculations?

What an interesting question! Why didn't you submit your name for my addressing the answer? In our laboratory at the Jones Institute for Reproductive Medicine in Norfolk Virginia, we have seen the answer to this question many times and there is quite a bit of variance from patient to patient. The WHO (World Health Organization) published values for normal sperm count is, in its latest edition, 20 million or more per milliliter. Sometimes the first patient sample collected for intrauterine insemination or combination with the wife’s eggs is so poor, for a number of reasons, that it can’t be used even though the eggs have already been collected. More often than not, if the husband collects a second sample within two hours of the first sample, the second one will be much better and quite usable in comparison with the first. We have determined, with questioning of the patients, that the problem in these cases is often a long abstinence time due to the husband and wife thinking that they need to "store up" a lot of sperm to be sure this assisted reproductive technology (ART) procedure will work. These ART procedures are rather expensive and so you can see why a couple would want to help the situation in this way. However, the sperm stored in the epididymis for longer than about 5 days can actually begin to deteriorate and be below normal count, motility, and, most importantly, be below normal functional level for fertilization. This is highly variable from man to man and there is a wide range of optimal time for any large group of men that is studied.

What we have found in the research laboratory (not using patients) with normal fertile men, (having fathered a child within the last 12 months) that have had exactly 5 day of abstinence before the study starts, is that the second sample, if collected within 12 hours of the first, will be as much as 50% less in count but as much as 75% better in motility. After that second sample, any further collection of samples within a few hours of the preceding sample, has a count that falls off rapidly into values below the normal of 20 million per milliliter. Again, there is a tremendous amount of variability between men. As a point of interest, it seems that smoking, alcohol, and both recreational and some prescription drugs can have a very negative effect on sperm function and these things seem to be cumulative in their negative effect.