One of the causes of aspermia is retrograde ejaculation, because of that the sperm is kept into the bladder and the final ejaculate is 0 mL.[1] It can be brought on by excessive drug use, or as a result of prostate surgery. It can also be caused by alpha blockers such as tamsulosin and silodosin.
It is important not to confuse aspermia with azoospermia, which is a pathological condition in which ejaculation occurs but no sperm are found in the semen. In aspermia, spermatozoa are produced, but they cannot be ejaculated. The sperm remain in the urinary bladder, where they die due to the acidic environment of the urine. To prevent this death of the sperm, oral bicarbonate is administered for a while, which bases the urine, so that the sperm are no longer exposed to such a hostile environment and could be collected from the urine to be used in IVF.