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Obstructive azoospermia refers to no sperm in a man's semen, as a result from problems with sperm delivery. Obstructive azoospermia accounts for around 40 percent of azoospermia cases. Most commonly, obstructive azoospermia results from previous vasectomy, but there are other causes.
Causes of Obstructive Azoospermia
Problems with the ductal system or issues with ejaculation can cause obstructive azoospermia. The ducts can be missing, or blocked, or the man could have an absence of the vas deferens, the tube that transports sperm for ejaculation.
Obstructive azoospermia can also be caused by problems with ejaculation. There may be problems with emission, the process by which the sperm is deposited into the urethra before ejaculation. This can be caused by neurological damage from surgery, diabetes, or spinal cord injury.
Treatments for Obstructive Azoospermia
Men who have obstructive azoospermia may need surgery to correct the obstruction. This surgery may make natural pregnancy possible without assisted reproductive technology, such as IUI, IVF and ICSI.
A surgery called a vasoepididymostomy can be performed in men with an epididymal
obstruction, which can prevent the sperm from entering into the ejaculate. The American Society for Reproductive Medicine estimates that 20 to 40 percent of couples in which the male receives this procedure can achieve a pregnancy without assisted reproductive techniques.
For men with an ejaculatory duct obstruction, a technique called the transurethral resection of the ejaculatory duct (TURED) may be recommended. Following this procedure, sperm appears in the ejaculate of around 50 to 75 percent of patients. These patients have a pregnancy rate of 25 percent.
Pregnancy and Obstructive Azoospermia
If surgery is able to correct the obstruction causing azoospermia, couples may be able then to conceive naturally without the help of fertility treatments.
However, there are sperm retrieval techniques that can also allow for conception. Men with obstructive azoospermia may be able to father a child through retrieval of sperm directly through the testis or epididymis, followed by IVF or ICSI. Common methods of sperm retrieval include microsurgical epididymal sperm aspiration (MESA), percutaneous epididymal sperm aspiration (PESA), testicular sperm extraction (TESE), and percutaneous testicular sperm extraction (TESA).
Sperm retrieval can be performed on the same day that the eggs are removed from the female partner, or it can be done some time before. Many fertility clinics prefer to use fresh sperm. Repeated sperm retrievals can be performed, though there is a recommended wait of 3 to 6 months.
ICSI usually must be performed before IVF because retrieved sperm usually does not have the number of motile sperm necessary to permit IUI or IVF without ICSI.