What is the cause of azoospermia (absence of sperm in the semen)?

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From the Guidelines

Azoospermia, or the absence of sperm in the semen, is typically caused by either a blockage in the reproductive tract (obstructive azoospermia) or dysfunction in sperm production (non-obstructive azoospermia), as defined by the most recent guidelines from the American Urological Association and the American Society for Reproductive Medicine 1. The causes of azoospermia can be complex and multifaceted, involving various factors such as hormonal imbalances, genetic abnormalities, and physical obstructions.

  • Obstructive azoospermia is often associated with conditions like congenital bilateral absence of the vas deferens (CBAVD) or ejaculatory duct obstruction (EDO), which can be diagnosed through physical examination and imaging studies.
  • Non-obstructive azoospermia, on the other hand, may be caused by issues with sperm production, such as hypogonadotropic hypogonadism (HH) or testicular failure, which can be evaluated through hormone testing and genetic analysis. Some key points to consider in the diagnosis and management of azoospermia include:
  • The importance of karyotype testing and Y-chromosome microdeletion analysis in identifying underlying genetic causes of azoospermia, particularly in cases of non-obstructive azoospermia 1.
  • The role of hormone testing, including FSH, LH, and testosterone levels, in evaluating sperm production and identifying potential hormonal imbalances 1.
  • The use of assisted reproductive technologies (ART) such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in treating azoospermia, particularly in cases where sperm retrieval is possible 1. It is essential to approach each case of azoospermia with a comprehensive evaluation and individualized treatment plan, taking into account the underlying cause and the patient's overall health and fertility goals. Men experiencing azoospermia should consult a urologist or reproductive specialist for a thorough assessment and discussion of treatment options, which may include medical therapy, surgical intervention, or assisted reproductive technologies 1.

From the Research

Causes of Azoospermia

The causes of azoospermia can be classified into two main categories: obstructive azoospermia and non-obstructive azoospermia 2, 3, 4.

  • Obstructive azoospermia occurs when there is a blockage in the reproductive tract, preventing sperm from being released into the semen.
  • Non-obstructive azoospermia occurs when there is a problem with sperm production, resulting in no sperm being present in the semen.

Obstructive Azoospermia

Obstructive azoospermia can be caused by a variety of factors, including:

  • Congenital absence of the vas deferens 2
  • Idiopathic epididymal obstruction 2
  • Infections 2
  • Vasectomy 2
  • Iatrogenic injuries to the male reproductive tract 2
  • Ejaculatory duct obstruction (EDO) 3
  • Epididymal obstruction 3

Non-Obstructive Azoospermia

Non-obstructive azoospermia can be caused by a variety of factors, including:

  • Primary hypogonadism 5
  • Secondary hypogonadism 5
  • Defects in androgen synthesis and/or response 5
  • Defective spermatogenesis and sperm maturation 5
  • Mixed picture of the above conditions 5

Diagnosis and Treatment

Diagnosis of azoospermia involves a combination of history, physical examination, laboratory testing, and imaging studies 2, 3, 4.

  • Treatment options for obstructive azoospermia include microsurgical reconstruction, sperm retrieval, and assisted reproduction 2, 3, 4.
  • Treatment options for non-obstructive azoospermia include medical management, sperm retrieval, and assisted reproduction 2, 4, 5.
  • Exosomal microRNAs in seminal plasma have been identified as potential biomarkers for predicting the origin of azoospermia and the presence of sperm in testicular tissue 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Causes of azoospermia and their management.

Reproduction, fertility, and development, 2004

Research

[Surgical treatment of obstructive azoospermia: a report of 56 cases].

Zhonghua nan ke xue = National journal of andrology, 2010

Research

Review of Azoospermia.

Spermatogenesis, 2014

Research

Nonobstructive azoospermia: an etiologic review.

Asian journal of andrology, 2024

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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