BIOLOGY Volume 3 - A Guide to General Biology - 2004

21. REPRODUCTION

21.9. Human Intervention in Reproduction

21.9.3. Infertility

Providing an exact definition of Infertility is difficult because this condition exists in varying degrees. For example, the monthly chance of conception for a fertile couple not using contraceptives is about 15%. A useful working definition of infertility can be formulated as the inability to achieve Pregnancy after a full year of trying. In such cases, medical professionals consider an examination of the couple to be justified.

Structure/149.html">The problem of infertility is surprisingly common. One in eight couples wishing to conceive encounters difficulties. The woman is usually blamed for this; however, it is now established that the man is at fault almost as often. Unfortunately, much less is known about Male infertility, whereas women have been studied much more thoroughly in this regard, partly due to traditional views in medicine. For many people, children are the main goal in life and the meaning of their existence. Being deprived of the opportunity to have children causes them ineffable suffering and emotional pain. People are often ready to do almost anything to have a child and are willing to pay large sums of money for Treatment. Therefore, everything related to the treatment of infertile couples requires a high degree of responsibility.

The most common causes of infertility and its treatments are discussed below.

Female Infertility

OVULATORY DISORDERS. In approximately 30% of cases, female infertility is caused by ovulatory disorders, with 70% of these disorders having hormonal causes. Sometimes the Hypothalamus or Pituitary Gland fails to secrete Hormones normally, leading to disturbances either in follicle development (FSH deficiency) or in egg release (LH deficiency). Another cause may be impaired synthesis of estrogen and/or progesterone by the Ovaries. In some cases, physical damage to the ovaries, their absence, or impaired function is possible, with the impaired function potentially caused by severe emotional distress or physical stress.

Ovulatory disorders are treatable in more than 90% of cases. Hormonal imbalances can be normalized using synthetic analogues of natural hormones. Most commonly, clomiphene is used for this purpose—a synthetic drug similar to estrogen that stimulates ovulation by triggering the release of FSH by the pituitary gland. Another estrogen-like substance is tamoxifen. Both drugs are available in tablet form, which is usually taken for five days shortly after the beginning of the Menstrual cycle. If the problem is impaired egg release, it is corrected through injections of human chorionic gonadotropin (hCG), which is chemically very similar to LH and acts as its substitute. hCG is injected during the expected mid-cycle LH surge. These “fertility drugs” are potent and can also be used when other remedies fail. They contain Pituitary Hormones—FSH and LH, or FSH alone. However, these drugs can induce the release of multiple eggs per month, creating a risk of Multiple pregnancy. This risk can be reduced by performing ultrasound monitoring and carefully regulating hormone levels in the body.

An alternative strategy consists of injecting GnRH, a hormone synthesized by the hypothalamus. This hormone can be synthesized artificially and administered in discrete doses using a small pump attached to the upper arm to mimic the natural activity of the hypothalamus.

FALLOPIAN TUBE BLOCKAGE. In roughly one-third of cases, female infertility is caused by blockages in the Fallopian tubes. The tubes may become completely blocked, although this does not usually happen. Infections leave behind scar tissue that creates partial or complete tube blockage, narrowing, or damage to the lining. Another problem is adhesions, As a result of which the tubes may become bound to other Organs, such as the Uterus. Adhesions can form when the body repairs damage in a particular area, sometimes occurring after surgical interventions. This can hinder the natural Movements of the Fallopian tubes required for capturing and transporting eggs.

Blockage can be associated with infectious diseases, most commonly pelvic inflammatory disease (PID) caused by Bacteria that are normally harmless. These diseases are more common in women with multiple sexual partners and in women using intrauterine devices (IUDs). Other infections can occur following childbirth, spontaneous Miscarriage, or Induced abortion. Fallopian tube blockage can also be congenital, although such cases are rare.

Fallopian tube blockage can likewise be caused by Endometriosis. In this condition, patches of the endometrium (the uterine lining) detach and begin to grow in other locations, such as inside or around the ovaries or Fallopian tubes.

The best way to diagnose tubal blockage is hysterosalpingography. A radiopaque dye is introduced into the uterus, which enters the tubes if they are patent. Recently, laparoscopy has also been widely used for examination (see the "IVF" section below).

Treatment for tubal blockages is most often surgical. Surgery is performed using a Microscope (microsurgery) because the tubes are very delicate. Lasers are used with some success. Sometimes the blocked section of the tube is removed and its ends are reconnected. Adhesions are comparatively easy to remove.

UTERINE ABNORMALITIES. In about 5—10% of cases, infertility is caused by uterine damage. Here, the problem is not getting pregnant, but rather sustaining the pregnancy and preventing Spontaneous Abortion (miscarriage). Complications can arise almost immediately after Fertilization (failure of implantation) or at later stages of pregnancy. Sometimes infertility may be associated with fibroids—benign tumors growing from the uterine walls. Similar but smaller growths called polyps can have the same effect. Fibroids and polyps are fairly easy to remove surgically. Adhesions inside the uterus can lead to the fusion of the uterine walls. Fused areas can be removed surgically. IVF or infections can cause inflammation, which is treated with Antibiotics. Less commonly, infertility is associated with a congenital anomaly, such as the absence, small size, or morphological abnormalities of the uterus.

CERVICAL DAMAGE. The cervix can be damaged as a result of abortion or difficult childbirth. Scar tissue frequently narrows the cervix or stops the secretion of mucus necessary for sperm to enter the uterus. Sometimes the cervix may become dilated, which greatly increases the likelihood of spontaneous miscarriage after three months of pregnancy. In all the cases described, surgical intervention is employed.

SPERM Antibodies. In some rare instances, women produce antibodies against their husbands' sperm. These antibodies are found in the cervix, uterus, and Fallopian tubes. Treatment Methods for this vary; in particular, immunosuppressive drugs are used, but the best method is probably IVF (see below).

Male Infertility

AZOOSPERMIA. Azoospermia refers to the absence of sperm in the seminal fluid. In about 5% of cases of male infertility, sperm are simply not produced, but even if they are, it does not mean they will enter the seminal fluid, as the ducts between the Testes and Seminal Vesicles may be blocked (see Fig. 21.32). Blockage can occur due to scarring from a past infection or physical injury. Causes of infection may include tuberculosis or Gonorrhea. Sometimes the blockage is congenital.

Another cause of azoospermia can be disorders related to the ejaculation mechanism. One of many such causes is retrograde ejaculation, in which sperm, instead of exiting through the Urethra, enter the Urinary Bladder.

The inability to produce sperm can be the result of physical injury to the testes, and sometimes the result of rubella virus infection after Puberty. The cause may be linked to hormonal imbalances; in this case, it can be very difficult to correct. Fig. 21.57, A illustrates some of the causes of azoospermia.

LOW SPERM COUNT IN SEMINAL FLUID. This accounts for 90% of male infertility cases. Often the cause of such infertility cannot be determined; however, A number of factors (Fig. 21.57, B) potentially linked to this phenomenon have been identified.

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Fig. 21.57. A. Some causes and treatments for azoospermia, the inability to produce semen containing sperm. B. Some causes and treatments for oligospermia, a low sperm count in the semen.

ABNORMAL SPERM. Typically, a certain proportion of sperm are abnormal; for example, they may have two flagella or none at all, lack a HEAD, or have an unusual shape. If this proportion is sufficiently high, fertility is reduced. The causes of these abnormalities generally remain unknown, though in some cases they may be of hormonal origin or linked to infections.

AUTOIMMUNE REACTION. In approximately 5–10% of cases, male infertility may be caused by an immune reaction against one's own sperm. The man's body produces antibodies against its own sperm, resulting in a decreased count of viable Gametes. The causes of this phenomenon are unknown, and it is difficult to treat. The Use of corticosteroids carries an unacceptable risk of infection due to the suppression of the Immune Response. As an alternative, donor insemination may be recommended (see below).

PREMATURE EJACULATION. In these cases, the man reaches orgasm before the Penis enters the Vagina. This problem can often be overcome with experience.

IMPOTENCE. The inability to achieve and maintain a penile erection. This is primarily a psychological issue that can be addressed with the help of appropriate specialists.