Male infertility can result if the body doesn’t produce enough testosterone or gonadotropins, which includes follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Hormonal problems primarily can be traced back to either the primary glands (Hypothalamus, Thyroid, Pituitary) that produce the hormones or the glands that the hormones target (Prostate, Testes). If one of these glands malfunctions, this can cause problems in sperm production, or in the production of the milky nourishing fluids that make up semen.
Sperm comprise a surprisingly small fraction of the semen itself (5%). Approximately 100 – 400 million sperm are present per ejaculate and they can survive up to 5 days in fertile cervical fluid. Low sperm counts and sperm abnormalities may be caused by hormonal problems, anatomical problems, immunological problems or even environmental factors.
The following are sperm-related abnormalities:
Azoospermia: No sperm in the semen. In some cases, sperm is produced in the testes, but there is an obstruction or malfunction that prevents the sperm from being ejaculated.
Oligozoospermia: Low sperm count.
Asthenozoospermia: Sperm with poor or low motility that impede their ability to swim well enough to reach the egg.
Teratozoospermia: Ill shaped sperm causing limited ability to fertilize the egg.
Sperm can also be affected by the immune system. Possibly resulting from trauma or infection, the male body may produce antibodies that coat the sperm and cause the individual sperm to clump together.
Any sort of obstruction in the sperm ducts, vas deferens, or urethra can prevent the sperm from being ejaculated. A common cause of infertility, blockages can be caused by infections (including sexually transmitted diseases), and can sometimes be repaired to restore fertility. A structural blockage may require surgery or some other procedure, while a blockage caused by infection may clear up with antibiotics and not need surgery. If the structural blockage cannot be repaired, then a testicular biopsy can be done to retrieve sperm.
Physical abnomalities include:
A small bag of water might be present in the scrotum (the sac of skin surrounding the testicles). This rare condition can be treated surgically.
b) Retrograde ejaculation
Retrograde ejaculation occurs when semen is ejaculated into the bladder instead of exiting through the penis. Retrograde ejaculation is a malfunction in the valves that control the flow of urine versus semen through the urethra; this rare condition is sometimes the result of diabetes or the removal of the prostate gland.
If a man's system operates as it should, the valve between the bladder and the urethra constricts during ejaculation or conversely, the valve between the vas deferens and the urethra closes during urination.
c) Undescended testes (cryptorchidism)
The scrotum hangs outside the body because the temperature of the testes needs to be a few degrees cooler than body temperature for normal sperm production to occur. Fertility problems can develop if the testes do not descend into the scrotum within the first month or so after birth. Surgery can repair undescended testes, but permanent damage can sometimes result if the testes do not descend in childhood.
Varicose (enlarged) veins in the testicle cause varicocele. There is much debate about the relevance of a varicocele on fertility, but a prevailing theory is that the veins increase the temperature in the testicles. This heat weakens sperm and impedes sperm production. Varicocele can be surgically repaired.
A common reason for the absence of sperm in the ejaculate is a previous vasectomy. Men can elect to have a surgical procedure done to reverse the vasectomy.