Causes of Azoospermia

Azoospermia, the absence of sperm in the ejaculate, can be due to various factors affecting sperm production or the sperm delivery system. The causes are generally categorized into obstructive and non-obstructive.

1. Obstructive Azoospermia Causes

This occurs when sperm are being produced in the testicles but cannot make their way into the semen due to a blockage or obstruction in the reproductive tract. Causes include:

Congenital Conditions: Some men are born with blockages or structural abnormalities in the reproductive tract. For instance, men with congenital bilateral absence of the vas deferens (CBAVD) have no vas deferens, the tube that carries sperm from the testicles to the urethra.
Infections: Previous infections, such as sexually transmitted infections (STIs) or epididymitis, can cause scarring and blockages in the reproductive tract.
Surgical Procedures: A history of surgeries, like a vasectomy (performed to prevent pregnancy), can result in obstruction.
Trauma or Injury: Any injury to the reproductive organs can lead to blockages or damage to the sperm pathways.
Cysts: Conditions like cysts in the seminal vesicles or other parts of the reproductive tract may obstruct sperm flow.

2. Non-Obstructive Azoospermia Causes

In non-obstructive azoospermia, the issue lies with sperm production itself. The testicles are either not producing enough sperm or not producing any at all. Causes include:

Genetic Disorders: Conditions like Klinefelter syndrome (where a man has an extra X chromosome) or Y chromosome microdeletions can affect sperm production.
Hormonal Imbalances: Hormonal issues, such as low levels of gonadotropins (FSH and LH) or elevated levels of prolactin, can impact the testicles’ ability to produce sperm. Disorders of the pituitary gland or hypothalamus can also lead to hormonal disruptions.
Testicular Failure: This occurs when the testicles lose their ability to produce sperm due to damage. It can be caused by factors such as:
- Undescended Testicles: If the testicles did not descend properly during childhood, they may not function correctly.
- Chemotherapy or Radiation: Cancer treatments can damage the testicular tissue, leading to sperm production failure.
- Varicocele: Enlarged veins in the scrotum can affect sperm production in some cases.
Environmental and Lifestyle Factors: Exposure to environmental toxins, heavy metals, radiation, or excessive heat can negatively impact sperm production. Substance abuse, smoking, and chronic stress also play a role.
Autoimmune Disorders: In some cases, the body’s immune system may mistakenly attack sperm or sperm-producing tissues.
Infections: Severe infections, such as mumps orchitis (a complication of mumps affecting the testicles), can lead to long-term damage and impaired sperm production.
Medications and Drugs: Certain medications, like anabolic steroids or long-term use of some antibiotics, can affect sperm production.
Age: Although sperm production doesn’t stop entirely with age, the quality and quantity can decline, increasing the risk of azoospermia.