What is oligoasthenozoospermia?

Oligoasthenozoospermia: Definition and Clinical Implications

Oligoasthenozoospermia is a condition characterized by both low sperm concentration (oligozoospermia) and reduced sperm motility (asthenozoospermia) in the semen, significantly impacting male fertility potential. 1

Definition and Diagnostic Criteria

Oligoasthenozoospermia is diagnosed through semen analysis when the following parameters are identified:

• Oligozoospermia: Sperm concentration less than 16 million/mL (WHO reference limit) 1
• Asthenozoospermia: Progressive motility less than 30% or total motility (progressive + non-progressive) less than 42% 1

According to the 2024 AUA/ASRM guidelines, at least two semen analyses obtained a month apart should be considered for diagnosis, especially if the first analysis shows abnormal parameters, as semen parameters can fluctuate substantially between tests 1.

Etiology and Risk Factors

Oligoasthenozoospermia can result from various factors:

• Genetic factors: Karyotype abnormalities and Y-chromosome microdeletions, particularly in men with sperm concentrations <5 million/mL 1
• Lifestyle factors: Obesity, smoking, and excessive heat exposure may contribute to poor semen parameters 1
• Oxidative stress: Increased reactive oxygen species (ROS) production damages sperm cell structure, DNA integrity, and mitochondrial function 2
• Varicocele: May affect sperm production and function 1
• Hormonal imbalances: Particularly involving the hypothalamic-pituitary-gonadal axis 1
• Idiopathic causes: In many cases, the exact cause remains unknown 3

Clinical Evaluation

A comprehensive evaluation should include:

1. Detailed reproductive history 1
2. Physical examination to assess:
   • Testicular size and consistency
   • Presence of varicocele
   • Signs of hypogonadism
   • Examination of epididymides and vas deferens 1, 4
3. Laboratory testing:
   • Semen analysis (at least two tests)
   • Hormonal evaluation (FSH, LH, testosterone)
   • Genetic testing for men with severe oligozoospermia (<5 million/mL):
     • Karyotype analysis
     • Y-chromosome microdeletion testing
     • CFTR gene mutation analysis if congenital bilateral absence of vas deferens is suspected 1, 4
4. Imaging:
   • Scrotal ultrasound to evaluate testicular structure and identify varicocele 4

Health Implications

Oligoasthenozoospermia has implications beyond fertility:

• Metabolic health: Men with low sperm counts have higher risk of metabolic syndrome, higher BMI, waist circumference, and abnormal lipid profiles 5
• Hormonal health: 12-fold increased risk of hypogonadism in men with low sperm counts 5
• Bone health: Higher prevalence of osteoporosis/osteopenia (51%) in men with hypogonadism associated with poor semen parameters 5
• Long-term health: Evidence suggests infertile men may have higher long-term morbidity and mortality than fertile controls 5

Management Approaches

Management should be guided by identified causes:

1. Lifestyle modifications:

   • Weight loss for obese patients
   • Smoking cessation
   • Avoiding excessive heat exposure 1

2. Treatment of specific causes:

   • Varicocele repair if clinically significant and associated with abnormal semen parameters 1
   • Hormonal therapy for specific endocrine abnormalities 1

3. Antioxidant therapy:

   • Some evidence suggests benefit from antioxidant supplementation (vitamin C, vitamin E, coenzyme Q10), but the AUA/ASRM guidelines note insufficient data to routinely recommend their use 1, 6

4. Assisted reproductive techniques:

   • Intrauterine insemination for mild cases
   • In vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI) for more severe cases 4

Important Considerations

• Genetic counseling is essential before assisted reproduction for men with genetic abnormalities 1
• Comprehensive health assessment should be considered given the association between poor semen parameters and general health issues 5
• Regular monitoring of hormonal status and bone health may be warranted in men with oligoasthenozoospermia and hypogonadism 5
• Avoid testosterone replacement therapy when attempting to achieve pregnancy, as it can suppress spermatogenesis 4

Oligoasthenozoospermia represents not just a fertility concern but potentially a marker of overall male health, warranting thorough evaluation and comprehensive management.