The body’s endocrine (hormonal) system controls sperm development, which occurs in the ducts of the testes. Sperm is carried in the semen, which usually has a normal volume range of 2 to 5 milliliters per ejaculation, or about one-fourteenth to one-sixth of a fluid ounce. Sperm count refers to the number of sperm cells per milliliter of semen. Men with 10 million or fewer sperm per milliliter are considered sub-fertile. Approximately 20 million or higher is considered average, and 40 million sperm or higher per milliliter indicates increased fertility.
If sperm have normal movement, at least one-half of the sperm will demonstrate rapid or slow progressive movement immediately after the sample liquefies, which is then sustained for at least three hours. The number of living sperm in a sample determines sperm vitality. At least 50 percent of ejaculated sperm are alive in a normal sample. Sperm morphology is assessed by the physical appearance of individual sperm, notably the head and tail characteristics, which should be normal in at least 30 percent of the sperm.
Azoospermia is a condition where no sperm are present in a man’s semen. This could be caused by a blockage of the tubes connecting the testes with the urethra (vas deferens), scarring in the tubes, missing tubes, a vasectomy, a failed vasectomy reversal, an infection, or inability to ejaculate due to spinal cord injury or psychological reasons.
There are often no symptoms for this disorder. Men with azoospermia may even have a normal ejaculation process. Fortunately, state-of-the-art reproductive technologies make it possible for many of these men to overcome their unique fertility challenges and have children. In vitro fertilization (IVF) with ICSI (Intracytoplasmic sperm injection) is one solution.
The first step in diagnosing male infertility is to evaluate a sperm sample. A fertility doctor usually works with the patient’s urologist to reach this goal. The male can provide a sample either through masturbation, stimulation by electricity, or by undergoing urological surgical procedures (MESA, PESA, or TESE). Most sperm-retrieval procedures are performed under local anesthesia in about a half-hour, and may cause temporary and mild pain and swelling.
Obstructions problems – such as a vasectomy, congenital absence of the tube connecting the testes with the urethra (vas deferens), or scarring of the vas deferens – can be treated with a microepididymal sperm aspiration (MESA) procedure, which is a surgical procedure to obtain sperm for laboratory use from the duct (epididymis) that stores and transports sperm from the testicles to the vas deferens. This procedure may be performed with a general or a local anesthetic. The urologist uses an operating microscope to examine the very small tubules of the epididymis that contain the sperm and collect fluid containing sperm. The fluid containing the sperm is collected and delivered to the IVF lab for processing, use, and freezing. If the fluid does not contain sperm or only dead sperm are present, then the urologist samples more areas of the epididymis until enough sperm are obtained. Extra sperm cells are commonly frozen for future use, so when eggs are available, the sperm can be thawed. Freezing of MESA-obtained sperm does not decrease the success of the treatment.
Percutaneous epididymal sperm aspiration (PESA) is a similar technique to MESA. A small needle is inserted through the skin of the scrotum to collect sperm from the epididymis, where sperm are usually stored after production in the testes. MESA, however, allows urologists to collect larger quantities of sperm, which produces larger quantities for freezing.
Testicular excisional sperm extraction (TESE) is performed when a man has no sperm stored or if testicular failure causes the lack of sperm rather than an obstruction. Testicular failure is uncommon, but causes include:
The TESE technique removes a small portion of testicle tissue through urologic surgery in order to explore the tissue for immature sperm that can then be utilized for ICSI with IVF. Success with TESE is limited by the quality of the sperm, and freezing of the TESE-obtained sperm seems to decrease the success. Therefore, the TESE procedure is ideally performed on the day of the egg retrieval.
Once the man has given a sperm sample, the next step is to evaluate its quality. Information about sperm count, sperm motility (amount of movement), and sperm morphology (general health of the sperm) helps individualize the patient’s infertility treatment. Depending on the severity of infertility, sometimes the best course is one of the least invasive treatments, which is usually a choice of either intrauterine insemination (IUI), or IVF if sperm motility renders IUI ineffective.
Treatment may include ICSI to fertilize the eggs for IVF in many cases of low sperm production. In this procedure, microscopic tools are used to inject a single sperm into the egg. The ICSI process optimizes the sperm number since only one motile sperm cell is required per egg. Without this method, the probability of fertilization and pregnancy for men with infertility problems is less than 1 percent. When combined with ICSI, the probability of fertilization and pregnancy reaches conventional IVF rates.