Male infertility

By Mayo Clinic staff

Original Article: http://www.mayoclinic.com/health/male-infertility/DS01038

Definition

Approximately 15 percent of couples are infertile. This means they aren't able to

conceive a child even though they've had frequent, unprotected sexual intercourse for a

year or longer. In about half of these couples, male infertility plays a role.

Male infertility is due to low sperm production, misshapen or immobile sperm, or

blockages that prevent the delivery of sperm. Illnesses, injuries, chronic health

problems, lifestyle choices and other factors can play a role in causing male infertility.

Not being able to conceive a child can be stressful and frustrating, but a number of

male infertility treatments are available.

Male fertility is a complex process. To get your partner pregnant, the following must

occur:

You must produce healthy sperm. Initially, this involves the growth and

formation of the male reproductive organs during puberty. At least one of your

testicles must be functioning correctly, and your body must produce testosterone

and other hormones to trigger and maintain sperm production.

Sperm have to be carried into the semen. Once sperm are produced in the

testicles, delicate tubes transport them until they mix with semen and are

ejaculated out of the penis.

There needs to be enough sperm in the semen. If the number of sperm in

your semen (sperm count) is low, it decreases the odds that one of your sperm

will fertilize your partner's egg. A low sperm count is fewer than 15 million sperm

per milliliter of semen or fewer than 39 million per ejaculate.

Sperm must be shaped correctly and able to move. If the movement

(motility) or shape (morphology) of your sperm is abnormal, the sperm may not

be able to reach or penetrate your partner's egg.

Medical causes

Problems with male fertility can be caused by a number of health issues and medical

treatments. Some of these include:

Varicocele. A varicocele is a swelling of the veins that drain the testicle. It's a

common cause of male infertility. This may prevent normal cooling of the testicle,

leading to reduced sperm count and fewer moving sperm.

Infection. Some infections can interfere with sperm production or sperm health,

or can cause scarring that blocks the passage of sperm. These include some

sexually transmitted infections, including chlamydia and gonorrhea; inflammation

of the prostate (prostatitis); and inflamed testicles due to mumps (mumps

orchitis).

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Antibodies that attack sperm. Anti-sperm antibodies are immune system cells

that mistakenly identify sperm as harmful invaders and attempt to eliminate them.

Tumors. Cancers and nonmalignant tumors can affect the male reproductive

organs directly or can affect the glands that release hormones related to

reproduction, such as the pituitary gland. In some cases, surgery, radiation or

chemotherapy to treat tumors can affect male fertility.

Hormone imbalances. Infertility can result from disorders of the testicles

themselves or an abnormality affecting other hormonal systems including the

hypothalamus, pituitary, thyroid and adrenal glands. Low testosterone (male

hypogonadism) and other hormonal problems have a number of possible

underlying causes.

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Chromosome defects. Inherited disorders such as Klinefelter's syndrome — in

which a male is born with two X chromosomes and one Y chromosome (instead

of one X and one Y) — cause abnormal development of the male reproductive

organs. Other genetic syndromes associated with infertility include cystic fibrosis,

Kallmann's syndrome, Young's syndrome and Kartagener syndrome.

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Certain medications. Testosterone replacement therapy, long-term anabolic

steroid use, cancer medications (chemotherapy), certain antifungal medications,

some ulcer drugs and certain other medications can impair sperm production

and decrease male fertility.

Diagnosing male infertility problems usually involves:

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Hormone testing. Hormones produced by the pituitary, hypothalamus and

testicles play a key role in sexual development and sperm production.

Abnormalities in other hormonal or organ systems may also contribute to

infertility. A blood test measures the level of testosterone and other hormones.

Treatments and drugs

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Hormone treatments and medications. Your doctor may recommend

hormone replacement or medications in cases where infertility is caused by high

or low levels of certain hormones or problems with the way the body uses

hormones.

Artigo publicado por Magdalena B.