Infertility

I

Introduction

Infertility, usually defined as the inability to conceive, carry, or deliver a healthy child. The most common cause of infertility is the inability to conceive. Doctors can determine why a couple is unable to conceive or bear children in about 90 per cent of cases, and they can correct infertility about 50 per cent of the time. Out of every 100 cases, about 40 can be traced to problems in the female, 30 to 50 to causes in the male, and the remainder to conditions in each partner that interact to cause sterility.

II

Causes

During sexual intercourse, sperm are delivered deep inside the vagina near the cervix. The sperm travel through the cervical mucus, into the uterus, and up the Fallopian tubes, where fertilization occurs. If it does occur, and other conditions are favourable, the fertilized egg will implant in the lining of the uterus, and pregnancy will begin. A dysfunction or an obstruction at any point in the process, however, prevents pregnancy from taking place.

Many things can cause infertility, ranging from hormonal or structural abnormalities, illness, and excessive use of alcohol and drugs to certain contraceptive techniques. The problem can occur at any point in the reproductive process. Initially, the woman may fail to ovulate or the man to produce adequate quantities of sperm; or, in later stages, structural problems of the uterus or cervix may make these organs incapable of supporting a pregnancy. Often the conditions contributing to sterility are temporary or reversible; such conditions may include poor nutrition, obesity, high fever associated with illness, or chronic fatigue.

In women, the most frequent cause of infertility is the failure to ovulate; the second most frequent cause is blocked Fallopian tubes. Less is understood about male infertility, because until recently men were assumed to be fertile if they were capable of sexual intercourse. As a partial consequence of this attitude, research on fertility has emphasized problems in women. Low sperm count, however, is the most common cause of infertility among men.

Reports indicate that the incidence of infertility is increasing, although accounting for part of this rise may be the number of couples seeking medical assistance after learning that infertility is often treatable. Doctors (usually gynaecologists for women and urologists for men) cite the following as other possible causes for the increase: the recent surge in the incidence of sexually transmitted diseases, which can severely damage both male and female reproductive systems if left untreated; and the popular use of birth-control pills and intrauterine devices for contraception, because infertility—both temporary and permanent—can occasionally follow their use.

Some doctors instead relate the apparent rise in infertility to the growing tendency to delay childbearing, often until the woman is in her 30s, because fertility in both men and women declines with age. A woman reaches her peak fertility at the age of 18 or 19, with little change until the mid-20s. Fertility then begins a slow decline to age 35, a sharper one to age 49, and a very rapid drop as the woman nears menopause. A man's fertility decline is not as rapid and has no clear-cut end, but a man of 50 is likely to be less fertile than he was at 25 or 30.

III

Treatment

Tests for fertility must show the following: that the woman is producing and releasing ova and that hormonal changes after the release are conducive to pregnancy; that the man is producing enough active sperm; and that no mechanical or chemical blocks exist between sperm and egg to prevent fertilization. Science has made great strides in correcting the malfunctions that prevent the occurrence of any of the above. In women, ovulation may be stimulated by hormones, and blocked Fallopian tubes can sometimes be opened surgically. In men, low sperm count is most frequently treated by hormone therapy; in some cases surgery is helpful. If both methods fail, a doctor may sometimes recommend artificial insemination, a process in which the male's sperm is collected, combined either with several other of his own ejaculates or with donor sperm, and then used to inseminate the woman.

In the early 1980s the widely publicized births of children conceived in a laboratory dish gave new hope to many women with damaged Fallopian tubes. This method of in vitro fertilization (IVF) is spreading rapidly, despite its relative high cost and the possible legal problems it could raise in some areas. Women have also been implanted with the ovum of another woman after it was fertilized by IVF or regular artificial insemination techniques.