What is sterilization?

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The surgical prevention of pregnancy, as performed on males through the cutting of the vas deferens (vasectomy) or on females through the blockage or cutting of the Fallopian tubes, the removal of the ovaries, or the removal of the uterus (hysterectomy).
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Indications and Procedures

Sterilization, of either a woman or a man, is a permanent method of surgical contraception that is used to render a couple incapable of conceiving children. Female sterilization involves the blockage or removal of the Fallopian tubes, the ovaries, or the uterus. Male sterilization involves the interruption of the vas deferens, the pathway of sperm from the testicles. The vas deferens may be reconnected, while many of the sterilization procedures performed on women are considered irreversible. Although the most frequently utilized types of female sterilization possess the potential for reversal at a later date, attempted reversals are often unsuccessful. Therefore, a woman choosing this type of contraception should be quite sure that she does not want another child. By the beginning of the twenty-first century, sterilization was the most prevalent form of contraception worldwide, with an estimated one hundred million women choosing the procedure. In the United States, approximately 700,000 women are sterilized each year. One reason that female sterilization is a popular form of contraception with women is because it represents a onetime effort that is usually both simple and the cause of only mild side effects. Another advantage of sterilization over the use of birth control pills is its high success rate: Less than a tenth as many sterilized women will become pregnant (as a result of improperly performed or incomplete procedures) as will women who rely on birth control pills for their contraception. The use of condoms, diaphragms, and all the other barrier pregnancy prevention devices are even less effective than birth control pills.

Before considering the various aspects of sterilization, it is useful to describe the female reproductive system and its biological operation. This organ system consists of two ovaries connected to paired Fallopian tubes that open up into the uterus. The entire system passes through a monthly menstrual cycle that is controlled by the female hormones progesterone and the estrogens. During each menstrual cycle, an ovary produces one egg (sometimes more) in a graafian follicle. The egg then enters one of the Fallopian tubes, which carries it to the uterus. If an egg is fertilized, it then implants in the endometrial tissue that lines the interior of the uterus and subsequently develops into an embryo.

Egg formation and uterus preparation for implantation are controlled by the female hormones. Once an egg implants, the uterus is kept in a state that optimizes pregnancy with the production of progesterone and related hormones, first by the corpus luteum (originally the graafian follicle that yielded the egg) and then by the placenta that forms from commingled uterine and fetal tissue. In the absence of fertilization, the menstrual cycle continues, most of the endometrium breaks down into the monthly menstrual flow, and the process begins over again.

Menstruation stops between forty-five and fifty-five years of age in most women, causing them to undergo a process called the menopause. After hundreds of repeated menstrual cycles since puberty, the graafian follicles stop producing eggs. Cessation of the menstrual cycle means that female hormone production stops almost entirely. Therefore, the menopause is accompanied by gradual atrophy of the sex organs and possible related symptoms, including hot flashes, depression, and irritability. When ovariectomy or hysterectomy is performed to achieve sterilization, these symptoms of the menopause may be induced prematurely.

For pregnancy to occur, then, a woman must have at least one functional ovary that produces eggs, an intact and operational Fallopian tube to transport the egg, and a functional uterus. The surgical methods that are used for sterilization must, therefore, make one of these reproductive organs nonfunctional. Most often, sterilization cuts and then blocks or removes the Fallopian tubes. Such interruption of the Fallopian tubes is the preferred form of female sterilization surgery for three reasons. First, these operations are relatively minor surgical procedures and are unlikely to be very risky. In addition, premature menopausal symptoms are not produced because the menstrual cycle continues. Finally, when carried out appropriately, interruption of the Fallopian tubes can sometimes be reversed if the patient changes her mind as a result of altered marital arrangements, lifestyle, or financial circumstances.

In many cases, a 1-centimeter to 1.5-centimeter section in the middle of each Fallopian tube is removed surgically or burned away via electrocoagulation. Alternatively, plastic or metal clips are used to close off each tube, or similar tube closure is effected by making a loop in each Fallopian tube and closing it off with a tight plastic ring or band.

Very frequently, the method that is used to damage the Fallopian tubes is a form of surgery called a laparoscopic procedure. The patient is given a general anesthetic, a very small incision is made close to the navel, and a flexible lighted tube—a laparoscope—is inserted into the incision. The laparoscope is equipped with fiber optics and enables an examining physician to see into the abdominal (peritoneal) cavity. Visibility of the Fallopian tubes and the other abdominal organs with laparoscopic examination is enhanced by pumping harmless carbon dioxide gas or nitrous oxide gas into the abdomen, to distend it. This process is called pneumoperitoneum.

After laparoscopic examination identifies the operation site in the peritoneal cavity, the surgical tools for cauterization, cutting, banding, and other aspects of interrupting the Fallopian tubes are passed through the laparoscope, and the chosen surgical interruption procedure is carried out. An entire laparoscopic procedure often takes less than thirty minutes, which is one of the reasons for its great popularity. In addition, women who choose to undergo such surgery can usually go home in a few hours and are fully recovered after only one to two days of postoperative bed rest, followed by a week or so of curtailed physical and sexual activity.

Despite the popularity of the laparoscopic procedure for sterilization, some physicians prefer to carry out sterilization by use of a larger surgical incision through which the tubes are altered directly. Despite the larger size of the incision, the physicians who use this method believe that it is safer and more sure of success and that it has a greater potential for reversibility.

Other methods for sterilization through Fallopian tube surgery are culdoscopy and chemical means. Culdoscopy, in which an optical instrument and surgical tools reach the Fallopian tubes through the uterus, has a somewhat lower success rate than do the laparoscopic procedure and the direct method. Chemical methods for tubal closure have also been attempted and are not viewed as viable because of a low success rate and frequent, serious postoperative complications.

The other avenues available for sterilization are ovariectomy (removal of the ovaries) and hysterectomy (removal of the uterus). Both of these types of sterilization surgery are much more serious and risky. In addition, ovariectomy and hysterectomy are totally irreversible. Ovariectomy, a more complicated procedure than the one inactivating the Fallopian tubes, is usually utilized only when both ovaries are diseased. This procedure produces an early menopause because most of a woman’s female hormones are made by the ovaries’ graafian follicles.

Hysterectomy is the most uncommon form of female sterilization because it requires even more extensive surgery and can have fatal complications. While the operation is sometimes carried out when a woman has completed her desired family, most hysterectomies are curative. They are performed in cases of very severe and widespread endometriosis and in the presence of other serious gynecological problems.

An alternative available to couples is sterilization of the male partner. This type of surgery, a vasectomy , is quite simple, brief, and relatively painless and only rarely results in physical or psychological complications. In addition, after vasectomy only one-tenth of a percent of involved couples experience undesired pregnancies. Vasectomy has no effect on sexual desire or male hormone production. It is also relatively easy to reverse such surgery, if so desired later in life. Consequently, the method has become quite popular. In the United States, for example, it was estimated in the early twenty-first century that approximately 500,000 men undergo this sterilization surgery each year.

Vasectomy involves the surgical interruption of the tube—the vas deferens—through which sperm leave the testicle. Vasectomy is carried out after identifying the position of each tube and injecting it with a local anesthetic. A one-inch-long incision is made in the scrotum, each tube is cut near its middle, a small piece of the tube is removed to keep the cut ends apart, and all the ends are closed with sutures, by cauterization, or with metal or plastic clips.

Vasectomy has a short recovery period and does not stop ejaculation during postoperative intercourse. It is important to note, however, that azoospermia (a lack of sperm in the ejaculate) is achieved only after six to fifteen postoperative ejaculations. Therefore, to ensure sterility, it is critical that the condition of azoospermia has been achieved before the patient carries out intercourse without using condoms or other protective measures. After two consecutive sperm counts indicate azoospermia, unprotected intercourse is deemed safe.

Uses and Complications

The most popular method of female sterilization is to block or damage both Fallopian tubes so that eggs cannot pass through them to the uterus. In some cases, the tubes are removed completely. While removal ensures successful sterilization, it is irreversible and considered too drastic by women who might someday wish to reverse the operation. Several popular alternatives to removal are the methods that interrupt the tubes, retaining the potential for reversal at a later date. Women undergoing this type of surgery are warned, however, that such reversal may be impossible.

When the Fallopian tubes are damaged but not entirely closed off, they may reconnect and cause an ectopic pregnancy , in which a fertilized egg implants in one of the tubes and begins to grow into a fetus. Ectopic pregnancy can be fatal to the pregnant woman, and when identified, it is corrected by surgical removal of the fetus. Although the cause of this problem is not clear, there is some thought that alteration of the interior wall of the tube or slowed passage of an egg through the tube may be the causative agent. Fortunately, ectopic pregnancy is relatively uncommon.

Whether the laparoscopic method or the direct approach is utilized, the best time to carry out female sterilization is at the end of a menstrual cycle; at this time, early pregnancies cannot be compromised. It is advised that the patient discontinue intercourse and the use of birth control pills for at least a month prior to the surgery. The cessation of intercourse eliminates the chance of unexpected pregnancy at the time of surgery, while stopping the use of birth control pills decreases the possibility of blood-clotting problems.

The complications of all types of Fallopian tube surgery can include internal bleeding, blood-clotting problems, injury to the intestines and the other abdominal organs, and abnormal postoperative menstrual cycles. It is estimated, however, that these complications occur in less than 1 percent of patients. A more frequent problem is the difficulty of restoring fertility by reconnecting the Fallopian tubes (with only a 20 to 40 percent success rate).

Hysterectomy is never a highly recommended female sterilization operation. Rather, it is used mostly in those cases where other uterine health problems are sufficiently severe to make the process sensible. These problems may include recurrent and heavy vaginal bleeding, severe endometriosis, and chronic pelvic inflammatory disease (PID). This extensive surgery results in a high rate of complications and a significant number of deaths.

A woman may seek sterilization when she is having an abortion or soon after giving birth to an undesired child. Such a decision, perhaps made hastily at a time of intense emotional stress, is not advisable. It is essential that a sterilization operation be performed only after careful reflection. Divorce or the death of a spouse and subsequent remarriage may cause a sterilized woman regret should she desire more children.

Severe psychological problems for both the patient and her family may accompany female sterilization. Therefore, it is highly recommended that these women, their families, and both partners in married couples consult a gynecologist and a psychological counselor before proceeding with female sterilization surgery.

In contrast to the complications associated with female sterilization, with vasectomy a day of bed rest and a week of avoidance of all strenuous physical activity usually produce complete recovery. Health complications occur in less than 5 percent of vasectomy patients. In addition, these problems are usually minor and almost never lead to fatalities. Skin discoloration, swelling, and oozing of clear fluid from the scrotum incision are common symptoms immediately following the surgery, but they spontaneously disappear as the healing process continues. Less frequently, inflammation and a condition called sperm granuloma can occur when sperm leak out of the cut portion of the vas deferens closest to the testicle. A granuloma produces severe inflammation, pain, and swelling. When this condition does not subside spontaneously, the granuloma must be removed surgically.

Perspective and Prospects

While surgical sterilization was first described in the nineteenth century, it was not widely available for contraception until the 1920s, nor did it become popular immediately. Though voluntary sterilization began slowly in the 1950s, its use accelerated until it became a popular form of fertility control in the industrial and developing nations of the 1970s.

A source of discontent with the sterilization techniques that are available is their total or poor reversibility when fertility reinitiation is desired later in life. This discontent has occurred because, with passing time, an unexpectedly large segment of sterilized men and women have come to regret their decisions regarding sterilization. All hysterectomies and Fallopian tube removals are forever irreversible, and a low reversibility rate is seen even in the two most popular—and potentially reversible—sterilization methodologies: Fallopian tube interruption and vasectomy.

Consequently, the development of sterilization surgery has been directed toward devising methods that will enable much larger incidences of reversibility, where desired. One direction has been to expand the understanding of Fallopian tube and vas deferens anatomy and functionality. Particularly useful results obtained include the realization that destruction of the nerves that control the operation of these organs can make the recovery of fertility incomplete or impossible even when excellent corrective surgery reverses the original interruption of continuity. This discovery has led to the development of more sophisticated interruption surgery that is less likely to damage the vas deferens or Fallopian tube nerve integrity. Some improvement of the reversibility of these operations has been obtained in this manner, but the overall results are still far from satisfactory.

Consequently, many other surgical techniques have been attempted, including the placement of removable plugs in the Fallopian tubes or of tiny, faucet-like valves in the vas deferens that allow or stop the ejaculation of sperm. Other useful methods to ensure reversible sterilization may include hormones, vaccines against eggs and sperm, and chemical treatments. It is hoped that improved antifertility methodologies will be developed that combine more reversible surgical sterilization, vaccines, chemicals, and various contraceptives.

Bibliography

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