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Problems With Sperm
Sperm may be too few in number, move too slowly, or be structurally abnormal, or their passage out of the body may be blocked or disrupted.
To be fertile, a man must be able to deliver an adequate quantity of normal sperm to a woman’s vagina, and sperm must be able to fertilize the egg. Conditions that interfere with this process can make a man less fertile.
Conditions that increase the temperature of the testes (where sperm are produced) can greatly reduce the number of sperm and the vigor of sperm movement and can increase the number of abnormal sperm. Some disorders of the testes, such as undescended testes and varicose veins (called a varicocele), increase the temperature of these organs. Effects of excessive or prolonged heat can last up to 3 months.
What Causes Infertility in Men?
Certain hormonal or genetic disorders may interfere with sperm production, as can other disorders.
Exposure to industrial or environmental toxins and use of certain drugs can reduce sperm production. Taking anabolic steroids, such as testosterone and other synthetic male hormones (androgens), lowers production of the pituitary gland hormones that stimulate sperm production.
Some disorders result in the complete absence of sperm (azoospermia) in semen. They include
Serious disorders of the testes
Disorders of other parts of the male reproductive system: blocked or missing vasa deferentia, missing seminal vesicles, and blockage of both ejaculatory ducts
The same genetic abnormality that causes cystic fibrosis can cause azoospermia, often by preventing both vasa deferentia from forming.
Azoospermia can also occur if semen, which contains the sperm, moves in the wrong direction (into the bladder instead of down the penis). This disorder is called retrograde ejaculation.
Doctors ask the man about his medical history and do a physical examination to try to identify the cause. Doctors ask about past disorders and surgery, use of drugs, and possible exposure to toxins. They check for physical abnormalities, such as undescended testes, and for signs of hormonal or genetic disorders that can cause infertility. Levels of hormones (including testosterone) may be measured in the blood.
A semen analysis, the main screening procedure for male infertility, is needed. For this procedure, men are often asked not to ejaculate for 2 to 3 days before the analysis. The reason is to make sure the semen contains as many sperm as possible. Then they are asked to ejaculate by masturbation into a clean glass jar, preferably at the laboratory site. For men who have difficulty producing a semen sample this way, special condoms that have no lubricants or chemicals toxic to sperm can be used to collect semen during intercourse.
The volume of the semen sample is measured. Whether the color, consistency, thickness, and chemical composition of semen are normal is determined. The sperm are counted. A low sperm count may mean that fertility is reduced, but not always. Sperm are also examined under a microscope to determine whether they are abnormal in shape, size, or movement.
If the semen sample is abnormal, the analysis may be repeated because samples from the same man normally vary greatly. Two or three samples, obtained at least 1 week apart, provide more accurate results than a single sample. If the semen still seems to be abnormal, the doctor tries to identify the cause. If there are too few sperm, doctors do genetic testing and measure levels of certain hormones, such as testosterone and follicle-stimulating hormone (which stimulates production of sperm in men). Also, urine may be checked for sperm after ejaculation to determine whether retrograde ejaculation is occurring.
Other tests can be done to evaluate sperm function and quality if routine tests of both partners do not explain infertility. These tests may check for antibodies to sperm, determine whether sperm membranes are intact, or assess the sperm's ability to bind to an egg and penetrate it. However, how useful these tests are is unclear.
If possible, the disorder causing the problem is treated. For example, varicoceles can be treated with surgery. Fertility may improve as a result, although this effect has not been proved.
Clomiphene, a drug used to trigger (induce) ovulation in women, may be used to try to increase sperm counts in men. However, whether clomiphene improves the sperm’s ability to move or reduces the number of abnormal sperm is unclear. It has not been proved to increase fertility.
If men have a low sperm count with motile sperm that appear normal, intrauterine insemination (placing semen directly in the uterus) may slightly increase their partner’s chances of pregnancy. A technique that selects only the most active sperm (washed sperm) is usually used. With washed semen, pregnancy usually occurs by the sixth attempt if it is going to occur.
In vitro fertilization, often with intracytoplasmic sperm injection (the injection of one sperm into one egg), and gamete intrafallopian tube transfer (GIFT) are much more complex and costly procedures. They are successful in treating many types of male infertility. Intracytoplasmic sperm injection is the most effective method.
Doctors can sometimes identify and retrieve a few sperm for intracytoplasmic sperm injection by doing a biopsy and examining the sample with a microscope to find the sperm. If no sperm are found, inseminating the woman with sperm from another man (a donor) may be considered. Because of the danger of contracting sexually transmitted diseases, including infection with human immunodeficiency virus (HIV) and hepatitis C, fresh semen samples from donors are no longer used in the United States. Risk of disease transmission is minimized by freezing donor sperm for 6 months or more, then retesting donors for infection. If their test results remain negative, the sample is thawed and used.
The partner of a man who has fertility problems may be treated with human gonadotropins to stimulate several eggs to mature and be released while intrauterine insemination is being tried. This approach may make pregnancy more likely.
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