Male factor infertility

The male partner is directly responsible for 25% of cases of infertility and is thought to play a contributory role in another 25%. Male factor infertility implies a lack of sufficient numbers of competent sperm, resulting in failure to fertilize the normal ovum.
Spermatogenesis requires testicular growth & differentiation & it is under endocrine control by FSH & paracrine control by androgens produced by LH-stimulated Leydig cells. Spermatogenesis comprises the mitotic division of spermatogonia & meiotic division of spermatocytes. These will develop into spermatids which then transform into mature spermatozoa in a process called spermiogenesis. Genes involved in spermatogenesis are expressed on the Y chromosome. In human this process takes 74 days.

Causes of male infertility:
• Disorders of spermatogenesis:
Impaired spermatogenesis could result from defect in any of the above mechanisms. The normal scrotal temperature is 1 degree lower than the rest of the body temperature and a rise in scrotal temperature is found in undescended testes and varicocele wherein increased scrotal temperature may impair spermatogenesis. Micro deletions of Y chromosomes may lead to defective spermatogenesis. Impaired sperm produc¬tion and sexual function may result from the intake of certain drugs such as some psychotropic drugs, anti-epileptic and antihypertensive agents, antibi¬otics and chemotherapeutic agents which adversely affect sperm production and sexual function.
• Sperm transport:
immotile spermatozoa are released into the lumen of the seminiferous tubules and travel to the ampulla of the vas deferens where they acquire motility. During ejaculation the semen is released by adrenergically mediated contractions of the distal epididymis and vas deferens. Spermatozoa are then mixed with the secretions of the accessory glands, prostate seminal vesicles, Cowpers and urethral glands.
Impairment of sperm transport can be seen in men with epididymal malformation, obstruction due to inflammation, enlargement or absence of vas deferens or immobile cilia syndrome. Sperm trans¬port is blocked or impaired after vasectomy.
Ejaculatory dysfunction
Ejaculatory dysfunction only occurs in 1-2 per cent of males with infertility. It could be due to anejaculation, premature ejaculation or retrograde ejacula¬tion and could be drug induced or idiopathic. Metabolic and systemic conditions like diabetes and multiple sclerosis may lead to impotence.
Other causes
Immunological factors such as antisperrn antibodies (IgG or IgA) and general infections may affect sperm function and lead to infertility.