Sperm Disorders

May 25, 2008

Sperm disorders include defects in sperm production and emission. Diagnosis is by semen and genetic testing. The most effective treatment is usually in vitro fertilization via intracytoplasmic sperm injection.

Spermatogenesis occurs continuously. Each germ cell requires about 72 to 74 days to mature fully. Spermatogenesis is most efficient at 34° C. Within the seminiferous tubules, Sertoli cells regulate maturation, and Leydig cells produce the necessary testosterone Some Trade Names
DELATESTRYL
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. Fructose is normally produced in the seminal vesicles and secreted through the ejaculatory ducts. Sperm disorders may result in inadequate quantity of sperm—too few (oligospermia) or none (azoospermia)—or defects in sperm quality, such as abnormal motility or structure.

Etiology

Spermatogenesis can be impaired by heat, disorders (GU, endocrine, or genetic), drugs, or toxins (see Table 1: Infertility: Causes of Impaired Spermatogenesis), resulting in inadequate quantity or defective quality of sperm.

Table 1

Causes of Impaired Spermatogenesis
Condition	Examples
Genetic disorders	Gonadal dysgenesis Klinefelter’s syndrome Microdeletions of sections of the Y chromosome (in 10–15% of men with severely impaired spermatogenesis) Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene
Heat	Exposure to excessive heat within the last 3 mo Fever

Causes of impaired sperm emission (obstructive azoospermia) include retrograde ejaculation into the bladder due to diabetes, neurologic dysfunction, retroperitoneal dissection (eg, for Hodgkin lymphoma), and prostatectomy. Other causes include obstruction of the vas deferens and congenital bilateral absence of the vas deferens or epididymis. Many affected men have mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and almost all men with symptomatic cystic fibrosis have congenital bilateral absence of the vas deferens.

Men with microdeletions affecting the Y chromosome can develop oligospermia via various mechanisms, depending on the specific deletion. Another rare mechanism of infertility is destruction or inactivation of sperm by sperm antibodies, which are usually produced by the man.

Diagnosis

When couples are infertile, the man should always be evaluated for sperm disorders. History and physical examination focus on potential causes (eg, GU disorders). Normal volume of each testis is 20 to 25 mL. Semen analysis should be performed. If there is oligospermia or azoospermia, genetic testing, including standard karyotyping, PCR of tagged chromosomal sites (to detect microdeletions affecting Y chromosome), and evaluation for mutations of the CFTR gene, should be undertaken. The partner of a man with a CFTR gene mutation should also be tested to exclude cystic fibrosis carrier status before his sperm is used for reproduction.

Before semen testing, the man is asked to refrain from ejaculation for 2 to 3 days. Because sperm count varies, testing requires ? 2 specimens obtained ? 1 wk apart; each specimen is obtained by masturbation into a glass jar, preferably at the laboratory site. If this method is difficult, the man can use a condom at home; the condom must be free of lubricants and chemicals. After being at room temperature for 20 to 30 min, the ejaculate is evaluated for volume (normal 2 to 6 mL), viscosity (normally, beginning to liquefy within 30 min; completely liquefied within 1 h), gross and microscopic appearance (normally, opaque, cream-colored, 1 to 3 WBC/high-power field), pH (normal 7 to 8), sperm count (normal > 20 million/mL), sperm motility at 1 and 3 h (normal > 50% motile), percentage of sperm with normal morphology (normal > 14% using 1999 WHO strict criteria), and presence of fructose (indicating at least one ejaculatory duct is patent). Additional computer-assisted measures of sperm motility (eg, linear sperm velocity) are available; however, their correlation with fertility is unclear.

If a man without hypogonadism or congenital bilateral absence of the vas deferens has an ejaculate volume < 1 mL, urine is analyzed for sperm after ejaculation. A disproportionately large number of sperm in urine vs semen suggests retrograde ejaculation.

Specialized sperm tests, available at some infertility centers, may be considered if routine tests of both partners do not explain infertility and in vitro fertilization or gamete intrafallopian tube transfer is being contemplated. The immunobead test detects sperm antibodies, and the hypo-osmotic swelling test measures the structural integrity of sperm plasma membranes. The hemizona assay and sperm penetration assay determine the ability of sperm to fertilize the egg in vitro.

If necessary, testicular biopsy can distinguish between obstructive and nonobstructive azoospermia.

Treatment

Underlying GU disorders are treated. For men with sperm counts of 10 to 20 million/mL and no endocrine disorder, clomiphene Some Trade Names
CLOMID
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citrate (25 to 50 mg po once/day taken 25 days/mo for 3 to 4 mo) can be tried. Clomiphene Some Trade Names
CLOMID
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, an antiestrogen, may stimulate sperm production and increase sperm counts. However, whether it improves sperm motility or morphology is unclear, and increased fertility has not been confirmed.

If sperm count is < 10 million/mL or clomiphene Some Trade Names
CLOMID
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is unsuccessful in men with normal sperm motility, the most effective treatment is usually in vitro fertilization with injections of single sperm into single eggs (ie, intracytoplasmic sperm injection). Alternatively, intrauterine insemination using washed semen samples and timed to coincide with ovulation is sometimes tried. Pregnancy is usually achieved by the 6th treatment cycle if it will occur at all.

Decreased number and viability of sperm may not preclude pregnancy. In such cases, fertility may be enhanced by controlled ovarian hyperstimulation of the woman plus artificial insemination or other assisted reproductive techniques (eg, in vitro fertilization, intracytoplasmic sperm injection).

If the male partner cannot produce enough fertile sperm, a couple may consider insemination using donor sperm. Risk of AIDS and other sexually transmitted diseases is minimized by freezing donor sperm for ? 6 mo, after which donors are retested for infection before insemination proceeds.

Last full review/revision November 2005

Content last modified November 2005

Article Source: Merck.com

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