What is Azoospermia?
Most fertile men have a sperm concentration of at least 15 million sperm per milliliter of semen. Azoospermia is when a man produces semen, but it does not contain any sperm. Diagnosis of azoospermia can be made by obtaining at least two semen analyses that show no sperm. There are two types of azoospermia:
- Obstructive Azoospermia (OA)
- Non-Obstructive Azoospermia (NOA)
In obstructive azoospermia, sperm is produced by the testicles, but a blockage or absence of vas deferens prevents the sperm from traveling to the ejaculate.
- Vasectomy: Vasectomy is the most common cause of obstructive azoospermia. A vasectomy is when the vas deferens, through which sperm travel from the testicles to the urethra during ejaculation, has been deliberately cut as a popular form of contraception.
- Cystic Fibrosis (CF): Men with this congenital lung disease typically have a bilateral absence of the vas deferens, a condition in which both vas deferens do not develop. In most cases, the testes still produce adequate sperm, which can be retrieved through a surgical procedure.
- Obstruction of the Ejaculatory Duct: The paired structures formed by the connection between the seminal vesicle and the vas deferens are called ejaculatory ducts. These ducts allow both sperm from the vas deferens and semen from the seminal vesicles to pass into the urethra. Congenital cysts or scarring from sexually transmitted diseases can cause blockage of these ducts.
- Surgical Complications: Bilateral hernia repairs can cause injury to the vas deferens, thereby blocking the normal flow of sperm into the ejaculate.
- Phimosis: Severe narrowing of the foreskin can block semen from coming out of the penis during ejaculation.
- Vasectomy Reversal: A vasectomy reversal (vasovasostomy or vasoepididymostomy) is a microsurgical procedure that reattaches the cut ends of the vas deferens, which allows sperm to enter the ejaculate in most cases.
- Testicular Sperm Aspiration or Extraction (TESA or TESE): A small incision or needle is used to extract testicular tissue containing sperm directly from the testicle. The sperm retrieved can then be used for in vitro fertilization (IVF).
- Transurethral Resection of the Ejaculatory Ducts (TURED): In men with ejaculatory duct obstruction, a TURED is a minor surgical procedure that can remove the blockage and allow for the flow of sperm and semen.
- Circumcision: The foreskin narrowing that occurs in phimosis can be treated with circumcision to remove the foreskin.
Non-obstructive azoospermia (NOA) is a condition in which not enough sperm is produced in order to have a detectable amount in the semen and is diagnosed in approximately 10% of infertile men.
There are two types of non-obstructive azoospermia: pretesticular and testicular causes.
Pretesticular Non-Obstructive Azoospermia
Pretesticular NOAs are conditions that disrupt the hormones needed by a man for normal creation of sperm.
- Hypogonadotropic Hypogonadism: This problem results from the brain’s pituitary gland failing to produce the hormones necessary for sperm or testosterone production, or both.
- Kallmann Syndrome: This genetic disorder is characterized by both hypogonadotropic hypogonadism and the lack of a sense of smell.
- Medications: testosterone replacement medications and anabolic steroids often cause sperm production to decrease or stop entirely.
- Other causes include rare types of pituitary tumors and hypothyroidism.
Testicular Non-Obstructive Azoospermia
In these conditions, the testes do not produce normal amounts of sperm.
- Varicoceles: Varicose veins in the scrotum can cause reduced sperm production in the testicles, but these rarely lead to azoospermia.
- Cryptorchidism: A history of undescended testicles, especially on both sides, can lead to impaired sperm production.
- Testicular Cancer: Testicular cancer and its treatment (surgery, radiation, chemotherapy) can lead to the absence of sperm.
- Gonadotoxins: Some industrial chemicals, radiation, and chemotherapy are toxic to the testes.
- Sertoli Cell-Only Syndrome: This is a condition in which testicles contain only Sertoli cells, which normally nurture immature sperm. There is a complete absence of sperm cells.
- Maturation Arrest: In this condition, a man’s sperm is unable to reach full maturity.
- Klinefelter Syndrome: This is a genetic syndrome in which a man has an extra X chromosome (XXY instead of XY) and is characterized by small, poorly functioning testicles leading to infertility and low testosterone.
Some treatment options include:
- Varicocelectomy: This is a surgical procedure in which the varicose veins in the scrotum are ligated.
- Medications: In men with non-obstructive azoospermia and low testosterone, fertility-friendly medications that help the body produce more testosterone (e.g. Clomid, Arimidex, hCG) can help increase sperm production as well. In some cases, men can get sperm to return to the ejaculate while in others, optimizing hormones can increase the chances that a sperm extraction surgery will be successful in finding sperm.
- Microsurgical Testicular Sperm Extraction (microTESE): In many men with non-obstructive azoospermia there is no sperm in the ejaculate, but the testes may produce small amounts of sperm. MicroTESE is a surgical procedure in which the tubules in the testes are selectively extracted under a microscope in order to search for sperm in a systematic way.