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When a man seeks medical help in becoming a father, one of the first conditions the physician will consider is varicocele. About 1 in 5 of all men have some degree of varicocele, but about 2 in 5 infertile men will be diagnosed with the condition.
A varicocele is a swollen vein in the scrotum. Varicoceles vary greatly in size. Sometimes the vein can only be detected when the man bears down hard on the peri-anal muscles as the doctor palpates the testicles. Sometimes the enlarged vein is visible across a room.
In varicocele, however, size does not really matter. Surgical correction of varicoceles of any size is about equally likely, or unlikely, to help a couple to become pregnant.
What Causes Varicocele?
A varicocele is essentially a varicose vein. When a vein becomes "varicose," it loses its ability to send blood back to the heart.
Just like veins in the legs, the veins that serve the testicles have to work against the force of gravity. When their valves are weak or absent, blood tends to accumulate rather than being sent back to the heart. In varicocele, blood tends to accumulate in an area known as the pampiniform plexus. The accumulation of blood heats the testes (the sperm-producing organs within the testicles), and reduces the amount of oxygen available to sperm-producing tissue.
What Effect Does Varicocele Have on Fertility?
It seems logical that poor circulation would lead to problems with sperm formation, but researchers have not yet found a direct link between varicocele and male infertility.
There is a common idea, for instance, that varicocele would cause shrinking testicles, so sperm production would be diminished. When men have a failure to produce a hormone called follicle stimulating hormone (FSH), however, the tested are often much smaller than they are with varicocele, yet sperm counts can be much greater.
There is also an idea that poor oxygenation causes progressive deterioration of the tissues in the testicles. There is no doubt that oxidative stress, with the formation of free radicals, causes DNA defects in sperm. However, this problem also occurs in men who do not have varicocele.
What Effect Does Surgical Correction of Varicocele Have on Fertility?
Because a varicocele presents an obvious problem, surgical correction of the variocele with a procedure known as varicocelectomy is often performed. The procedure may be done surgically, but nowadays most of the time it is performed as a percutaneous procedure. An interventional radiologist makes a small incision, usually in the groin, and threads a small pipe known as a catheter through a vein to the testicular vein. Then the radiologist injects a chemical to kill the tissue in the vein so that blood flow has to be redirected to surrounding, smaller veins.
Replacing a larger vein with several smaller veins may seem like an odd way to increase circulation, but the basic problem in varicocele is pressure. The testicular vein gets backed up with blood from the renal vein, because the renal vein is between two major arteries. Smaller blood vessels do a better job of increasing blood flow than the larger testicular vein, and more oxygen flows to the testicles. More blood flow almost always results in greater sperm production.
But greater sperm production does not automatically mean more babies. In fact, a Cochrane Reviews meta-analysis of eight studies show that couples in which the male partner has varicocelectomy have a 33% chance of getting pregnant within one year, while couples in which there is only counseling have a 36% chance of getting pregnant within that year.