Infertility Health Article

Male factors

Male infertility can be caused by a number of different characteristics of sperm. To check for these characteristics, a sample of semen is obtained and examined under a microscope (semen analysis). Four basic characteristics are usually evaluated:

• Sperm count refers to the number of sperm present in a semen sample. The typical number of sperm present in just one milliliter (ml) of semen is more than 20 million. A male with only 5–20 million sperm per ml of semen is considered subfertile, while a male with less than 5 million sperm per ml of semen is considered to be infertile.
• Sperm are examined to determine how well they swim (sperm motility) and to ensure that most have normal structure (morphology). Not all sperm within a specimen of semen will be perfectly normal. Some may be immature, and others may have abnormalities of the head or tail. A typical semen sample will contain no more than 25% abnormal forms of sperm.
• Volume of the semen sample is important; an abnormal amount of semen could adversely affect the ability of the sperm to successfully fertilize an ovum.
• The ability of the sperm to penetrate the outer coat of the ovum is also evaluated. This is accomplished by observing whether sperm in a semen sample can penetrate the outer coat of a hamster ovum. Fertilization cannot occur, of course, but this test is useful in predicting the ability of an individual's sperm to penetrate a human ovum.

Any number of conditions result in abnormal findings in the semen analysis. Men can be born with testicles that have not descended properly from the abdominal cavity into the scrotal sac, or may be born with only one testicle, instead of the normal two. Testicle size might be smaller than normal. Past infection (including mumps) can affect testicular function, as can a past injury. The presence of abnormally large veins (varicocele) in the testicles can increase testicular temperature, which decreases sperm count.

History of having been exposed to various toxins, drug use, excessive alcohol use, use of anabolic steroids, certain medications, diabetes, thyroid problems, or other endocrine disturbances can have direct effects on the formation of sperm (spermatogenesis). Problems with the male anatomy can cause sperm to be ejaculated into the bladder, or scarring from past infections can interfere with ejaculation.

Female factors

OVULATORY PROBLEMS. The first step in diagnosing ovulatory problems is to make sure that an ovum is being produced each month. A woman's body temperature in the morning is slightly higher around the time of ovulation. A woman can measure and record her temperatures daily, and a chart can be drawn to show whether or not ovulation has occurred. Luteinizing hormone (LH) is released just before ovulation. A simple urine test can be done to check if LH has been released around the time that ovulation is expected.

PELVIC ADHESIONS AND ENDOMETRIOSIS. Pelvic adhesions and endometriosis can cause infertility by preventing the sperm from reaching the egg or interfering with fertilization.

Pelvic adhesions are fibrous scars. These scars can be the result of past infections, such as pelvic inflammatory disease, or infections following abortions or prior births. Previous surgeries can also leave behind scarring. Pelvic adhesions cause infertility by blocking the fallopian tubes. The ovum may be prevented from traveling down the fallopian tube from the ovary or the sperm may be prevented from traveling up the fallopian tube from the uterus.

A hysterosalpingogram (HSG) can show if the fallopian tubes are blocked. This is an x-ray exam that tests whether dye material can travel through a woman's fallopian tubes. Scarring also can be diagnosed by examining the pelvic area through the use of a scope that can be inserted into the abdomen through a tiny incision made near the navel. This technique is called laparoscopy.

Endometriosis may lead to pelvic adhesions. Endometriosis is the abnormal location of uterine tissue outside of the uterus. When uterine tissue is implanted elsewhere in the pelvis, it still bleeds on a monthly basis with the start of the normal menstrual period. This leads to irritation within the pelvis around the site of this abnormal tissue and bleeding, and may cause scarring.

CERVICAL FACTORS. The cervix is the opening from the vagina into the uterus through which the sperm must pass. Mucus produced by the cervix helps to transport the sperm into the uterus. Cervical mucus can be examined under a microscope to diagnose whether cervical factors are contributing to infertility. An injury to the cervix or scarring of the cervix after surgery or infection can result in a smaller than normal cervical opening, which would make it difficult for sperm to enter. Injury or infection can also decrease the number of glands in the cervix, leading to a smaller amount of cervical mucus. In other situations, the mucus produced might be the wrong consistency to allow sperm to travel through. In addition, some women produce antibodies (immune cells) that identify sperm as foreign invaders and kill them. Finally, cervical stenosis is a rare cause of infertility.