Your doctor will be interested in any factor, including possible structural and other defects in the reproductive system, hormonal deficiencies, illness or even trauma that might be impairing your fertility. Their investigation will center on many possible combinations of factors, the most common of which are:
Sperm disorders: Problems with the production and development of sperm are the most common problems of male infertility. Sperm may be underdeveloped, abnormally shaped or unable to move properly. Or, normal sperm may be produced in abnormally low numbers (oligospermia) or seemingly not at all (azoospermia).
Varicoceles: These dilated scrotal veins are present in 16 percent of all men but are more common in infertile men—40 percent. They impair sperm development by preventing proper drainage of blood. Varicoceles are easily discovered on physical examination since the veins feel distinctly like a bag of worms. They may also be enlarged and twisted enough to be visible in the scrotum . This is the most common correctable cause of male infertility.
Retrograde ejaculation: Retrograde ejaculation occurs when semen pushes backwards into the bladder instead of out the penis . This is caused by the failure of nerves and muscles in the bladder neck to close during orgasm. It is one of several difficulties couples may have delivering sperm to the vagina during intercourse. Retrograde ejaculation can be caused by previous surgery, medications or diseases affecting the nervous system. Signs of this condition may include cloudy urine after ejaculation and diminished or “dry” ejaculation with orgasm.
Immunologic infertility: Triggered by a man’s immunologic response to his own sperm, antibodies are usually the product of injury, surgery or infection. In attacking the sperm, they prevent normal movement and function of the sperm. Although researchers do not yet understand just exactly how antibodies damage fertility, they know that these antibodies can make it more difficult for sperm to swim to the uterus and penetrate eggs.
Obstruction: Blocking sperm from its normal passage, obstructions can be caused by a number of factors, such as repeated infections, prior surgery (including vasectomy ), inflammation or development problems. Any portion of the male reproductive tract, such as the vas deferens or epididymis, can be obstructed, preventing normal transport of sperm from the testicles to the urethra, where it leaves the body during ejaculation.
Hormones: Hormones produced by the pituitary gland are responsible for stimulating the testicles to make sperm. Therefore, when levels are severely low, poor sperm development can result.
Genetics: Genetics play a central role in fertility, particularly since sperm carry half of the DNA mix to the partner’s egg. Abnormalities in chromosomal numbers and structure as well as deletions on the important Y chromosome present in normal males can also impact fertility.
Medication: Certain medications can affect sperm production, function and ejaculation. Such medications are usually prescribed to treat conditions like arthritis, depression, digestive problems, infections, hypertension and even cancer.