From the Guidelines
Male reproduction is a complex process that involves the production of sperm and male sex hormones, and any issues with this process can significantly impact fertility, morbidity, mortality, and quality of life. The testes, located in the scrotum, produce sperm cells through spermatogenesis and testosterone through the Leydig cells, as noted in the guidelines for male infertility diagnosis and treatment 1. This process begins at puberty and continues throughout most of a man's life, though sperm quality may decline with age. Sperm production requires slightly cooler temperatures than body temperature, which is why the testes are positioned outside the body cavity.
The male reproductive system includes the testes, epididymis, vas deferens, seminal vesicles, prostate gland, and penis. Sperm cells mature in the epididymis before traveling through the vas deferens during ejaculation. The seminal vesicles and prostate contribute fluids that nourish and protect sperm, forming semen. Testosterone is essential for developing and maintaining male secondary sex characteristics, including facial hair, deeper voice, and muscle mass. Factors affecting male fertility include age, lifestyle choices (smoking, alcohol consumption), environmental exposures, certain medications, and medical conditions like varicocele or hormonal imbalances, as updated in the recent guidelines for male infertility 1.
Some key terms related to male infertility include:
- Aspermia: Complete absence of semen in ejaculate
- Azoospermia: Absence of spermatozoa in the semen
- Oligozoospermia: Low sperm concentration in the semen
- Asthenozoospermia: Reduced sperm motility
- Teratozoospermia: Abnormal sperm morphology
- Normozoospermia: Normal semen parameters
- Retrograde Ejaculation: Condition where semen flows backward into the bladder instead of exiting through the urethra during ejaculation. Azoospermia is defined as absence of sperm in the ejaculate, and when a semen analysis shows azoospermia, the laboratory should then centrifuge the ejaculate and re-suspend the pellet in a small volume of seminal plasma and examine under wet mount microscopy for the presence of rare sperm, as recommended in the recent guidelines 1. Clinicians should recommend karyotype testing for males with primary infertility and azoospermia or sperm concentration <5 million sperm/mL when accompanied by elevated FSH, testicular atrophy, or a diagnosis of impaired sperm production. Regular health check-ups can help identify and address potential reproductive issues early, and it is essential to follow the most recent guidelines for the diagnosis and treatment of male infertility to improve morbidity, mortality, and quality of life outcomes 1.
From the Research
Male Reproduction Overview
- Male infertility is a significant issue, with up to 30% of fertility problems attributed to the man alone, and up to 90% of these cases due to low sperm count or low sperm quality or both 2.
- Testosterone replacement therapy, commonly used to treat late-onset hypogonadism (LOH), can lead to secondary spermatogenic failure and subsequent infertility due to its suppressive effect on the hypothalamic-pituitary-gonadal axis 3.
Causes and Risk Factors
- Low sperm count and low sperm quality are major contributors to male infertility, with various factors such as lifestyle, environmental exposures, and medical conditions influencing these parameters 2.
- Testosterone replacement therapy is a significant risk factor for male infertility, particularly if administered to men who desire to maintain future fertility 3, 4.
Diagnosis and Treatment
- Diagnosis of male infertility involves a comprehensive evaluation of semen parameters, hormonal levels, and medical history 5.
- Treatment options for male infertility include conventional strategies such as medication, surgery, and assisted reproductive techniques like in vitro fertilization (IVF) 2, 5.
- Cessation of testosterone replacement therapy can lead to recovery of spermatogenesis in some men, with up to 65% of men without other known causes for azoospermia recovering spermatogenesis within 6 months of discontinuation 3, 4.
Role of Testosterone in Male Reproduction
- Testosterone plays a crucial role in male reproductive health, affecting spermatogenesis, libido, and erectile function 6.
- Testosterone therapy can have beneficial effects on various aspects of men's health, including vascular endothelial function, mood, muscle strength, bone health, and sexual function, particularly in men with hypogonadism symptoms and low testosterone levels 6.