What is azoospermia?
Azoospermia is a lack of sperm in seminal fluid. If, after one year of unprotected sex, a pregnancy has not occurred, this means that the man, woman, or both, may have a fertility problem. In 40% of infertile couples, the male has a fertility problem.
How common is azoospermia?
About 1% of all men and 10%-15% of infertile men have azoospermia.
What are the types of azoospermia?
The male reproductive system is made up of the following:
- Testes, or testicles – produce sperm (male reproductive cells) in a process called spermatogenesis
- Seminiferous tubules – tiny tubes that make up most of the tissue of the testes
- Epididymis – tube into which mature sperm are moved and stored
- Vas deferens – tube that passes from the epididymis into the body cavity, then curves to connect with the urethra. Tightening of the vas deferens moves the sperm along, past the seminal vesicles and prostate gland, which add seminal fluid to the sperm to form semen.
- Urethra - tube that runs through the penis to eliminate urine from the bladder and semen from the vas deferens
Azoospermia can be grouped into three major types:
1) Pre-testicular causes (non-obstructive): Poor production of sex hormones prevents the testicle from making sperm. Can be caused by:
- Kallmann syndrome: A genetic (inherited) disorder carried on the X chromosome, marked by low levels of gonadotropin-releasing hormone (GnRH) and a loss of smell. GnRH stimulates the pituitary gland to secrete hormones that govern the reproductive organs.
- Disorders of the hypothalamus (a part of the brain) or pituitary gland, which can be caused by radiation treatments or certain medications, especially those used in chemotherapy.
2) Testicular causes (non-obstructive): defects in the structure or functioning of the testicles. Can be caused by:
- Anorchia (absence of the testicles)
- Cyptorchidism (testicles have not dropped into the scrotum)
- Sertoli cell-only syndrome (testicles fail to produce living sperm cells)
- Spermatogenic arrest (testicles fail to produce fully mature sperm cells)
- Klinefelter’s Syndrome; male carries an extra X chromosome (making his chromosomal makeup XXY instead of XY). The result is often infertility, along with lack of sexual or physical maturity, and learning difficulties.
- Mumps orchitis (inflamed testicles caused by mumps in late puberty)
- Reactions to certain medications
- Radiation treatments
- Diseases such as diabetes, cirrhosis, or kidney failure
- Varicocele (veins coming from the testicle are dilated, or widened)
3) Post-testicular causes (obstructive): Problems with ejaculation or an obstruction in the reproductive tract prevents sperm from being carried into the seminal fluid. This condition occurs in about 40% of men with azoospermia. Can be caused by:
- An obstruction or missing connection in the epididymis, vas deferens, or elsewhere in the reproductive system
- Congenital bilateral absence of the vas deferens (CBAVD): A genetic defect in which the vasa deferentia are absent at birth. The genetic mutation that causes CBAVD is also strongly associated with cystic fibrosis. Men with CBAVD have a high risk of being a carrier of cystic fibrosis. Female partners of men with CBAVD should have a gene mutation analysis to see if they are also a carrier in order to determine the risk of having a child with cystic fibrosis.
- Growth of a cyst
- Vasectomy (removal of all or part of the vas deferens with surgery)
What are the causes of azoospermia?
Genetics (inheritance) plays a role in 10%-15% of men with low or no sperm production. Defects in chromosomes (the structure inside a cell nucleus that contains genetic material) can affect the number, form, and size of sperm.
Defects can occur at different locations on the Y (male) chromosome. In some cases, a piece of the Y chromosome may be missing (microdeletion) and cause infertility.
Diagnosis and Tests
How is azoospermia diagnosed?
Azoospermia is diagnosed when, on two separate occasions, no sperm cells can be found in samples of centrifuged seminal fluid using a high-powered microscope.
A centrifuge is a laboratory instrument that spins a test sample at a high speed to separate it into its various parts. In the case of centrifuged seminal fluid, if sperm cells are present, they separate from the fluid around them and can be viewed under a microscope.
As part of the diagnosis, the doctor will take the patient’s medical history, including the following:
- Fertility success or failure in the past (ability to have children)
- Childhood illnesses
- Injuries or surgeries in the pelvic area (these could cause duct blockage or poor blood supply to the testicles)
- Urinary or reproductive tract infections
- sexually transmitted diseases
- Exposure to radiation or chemotherapy
- Any use of medications, past or present
- Abuse of alcohol, marijuana, or other drugs
- Recent fevers or exposure to heat, including frequent saunas or steam baths (heat kills sperm cells)
- Family history of birth defects, mental retardation, reproductive failure, or cystic fibrosis
The doctor will also conduct a physical examination, and will check:
- The overall maturation, size, and shape of the body and the reproductive organs
- Contents of the penis and scrotum
- If the vas deferens is present
- Tenderness or swelling of the epididymis
- The presence or absence of a varicocele
- The rectum for obstruction of the ejaculatory duct
The doctor may also order the following tests:
- Measurement of levels of hormones such as testosterone and follicle-stimulating hormone (FSH);
- Genetic testing
- X-rays or ultrasound of the reproductive organs to see if there are any problems with the shape and size, and to see if there are tumors, blockages, or an inadequate blood supply
- Imaging of the brain to identify disorders of the hypothalamus or pituitary gland
- In cases of normal-sized testes and normal hormone levels, a biopsy (tissue sampling) of the testes to learn if it is obstructive or non-obstructive azoospermia. A normal biopsy would mean that there is probably an obstruction at some point in the sperm transport system. Sometimes, any sperm found in the testes is frozen for future analysis or use in assisted pregnancy.
How is azoospermia treated?
Genetic testing and counseling are often an important part of understanding and treating azoospermia.
In cases of obstructive azoospermia, reconstruction or reconnection of obstructed or disconnected ducts can be performed. Hormone treatments may be possible in cases where the main issue is low hormone production.
If living sperm are present, they can be retrieved from the testes for the purpose of assisted pregnancy such as in vitro fertilization or intracytoplasmic sperm injection.
Men with non-obstructive azoospermia should receive genetic analysis before their sperm are used to perform any type of assisted fertilization, in order to learn if there are any genetic risks that may be passed to children.
How can azoospermia be prevented?
There is no known way to prevent the genetic problems that cause azoospermia. You can take the following measures to prevent azoospermia:
- Avoid activities that could injure the reproductive organs.
- Avoid exposure to radiation.
- Know the risks and benefits of medications that could harm sperm production.
- Avoid lengthy exposure of the testes to hot temperatures.
Outlook / Prognosis
What is the long-term outlook for those with azoospermia?
Pre-testicular and post-testicular causes of azoospermia are generally treatable. Testicular causes of azoospermia cannot be cured, but can be managed with testicular biopsy and subsequent in vitro fertilization.
- American Society for Reproductive Medicine. Evaluation of the azoospermic male. Fertil Steril 2008;90:S74-7.
- Gudeloglu A, Parekattil SJ: Update in the evaluation of the azoospermic male. Clinics (Sao Paulo). Feb 2013; 68(Suppl 1): 27-34.
- American Fertility Association: It’s In the Male
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This document was last reviewed on: 04/09/2014