Problems With Sperm
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. Temperature may be increased by exposure to excessive heat, disorders that produce a prolonged fever, undescended testes (a rare abnormality present at birth (see Section 23, Chapter 267)), and varicose veins in the testes (varicocele).
Certain hormonal or genetic disorders may interfere with sperm production. Hormonal disorders include hyperprolactinemia, hypothyroidism, hypogonadism, and disorders of the adrenal gland (which produces testosterone and other hormones) or pituitary gland (which controls testosterone production). Genetic disorders involve an abnormality of the sex chromosomes, as occurs in Klinefelter syndrome.
Other causes of reduced sperm production include mumps that affect the testes (mumps orchitis), injury to the testes, exposure to industrial or environmental toxins, and drugs. Drugs include androgens (such as testosterone), aspirin when taken for a long time, chlorambucil, cimetidine, colchicine, corticosteroids (such as prednisone), cotrimoxazole, cyclophosphamide, drugs used to treat malaria, estrogens taken to treat prostate cancer, marijuana, medroxyprogesterone, methotrexate, monoamine oxidase inhibitors (MAOIs--a type of antidepressant), nicotine, nitrofurantoin, opioids (narcotics), spironolactone, and sulfasalazine. Use of anabolic steroids may affect hormone levels and thus also interfere with sperm production. Excessive consumption of alcohol may reduce sperm production.
Some disorders result in the complete absence of sperm (azoospermia) in semen. They include serious disorders of the testes and blocked or missing vasa deferentia, missing seminal vesicles, and blockage of both ejaculatory ducts.
Occasionally, semen, which contains the sperm, moves in the wrong direction (into the bladder instead of down the penis). This disorder, called retrograde ejaculation (see Section 21, Chapter 240), is more common among men who have diabetes or who have had pelvic surgery, such as prostate removal. Infertility may result.
Diagnosis
Doctors ask the man about his medical history and perform a physical examination to try to identify the cause. Doctors 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.
Often, a semen analysis, the main screening procedure for male infertility, is needed. For this procedure, the man is asked not to ejaculate for 2 to 3 days before the analysis. Then he is asked to ejaculate, usually 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. An analysis based on two or three samples, obtained at least 2 weeks apart, is more reliable than an analysis based on a single sample.
The volume of the semen sample is measured. Whether the color and consistency of semen are normal is determined. The sperm are examined under a microscope to determine whether they are abnormal in shape, size, movement, or number.
If the semen sample is abnormal, the analysis may be repeated because samples from the same man normally vary greatly. If the semen still seems to be abnormal, the doctor tries to identify the cause. However, a low sperm count may indicate only that too little time had elapsed since the last ejaculation or that only some of the semen was deposited in the collection jar. Furthermore, a low sperm count does not mean that fertility is reduced, and a normal sperm count does not guarantee fertility.
Tests of sperm function and quality can be performed. One test detects antibodies to sperm. Another determines whether sperm membranes are intact. Still others can determine the sperm's ability to bind to an egg and penetrate it. Sometimes a biopsy of the testes is performed to obtain more detailed information about sperm production and the function of the testes.
Treatment
Clomiphene, a drug used to trigger (induce) ovulation in women, may be used to try to increase sperm counts in men. However, clomiphene does not improve the sperm's ability to move or reduce the number of abnormal sperm, and it has not been proved to increase fertility.
For men who have a low sperm count with normal sperm, artificial insemination may slightly increase their partner's chances of pregnancy. This technique uses the first portion of the ejaculated semen, which has the greatest concentration of sperm. A technique that selects only the most active sperm (washed sperm) is somewhat more successful. In vitro fertilization, often with intracytoplasmic sperm injection (the injection of a single sperm into a single egg), and gamete intrafallopian tube transfer (GIFT) are much more complex and costly procedures. They are successful in treating many types of male infertility.
For men who produce no sperm, 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), fresh semen samples from donors are no longer used. Instead, frozen sperm samples are obtained from a certified sperm bank, which has tested the donors for sexually transmitted diseases.
Varicoceles can be treated with surgery. Sometimes fertility improves as a result.
The partner of a man who has fertility problems may be treated with human gonadotropins, to stimulate several eggs to mature and be released (see Section 22, Chapter 254).
|
