Contraceptive efficacy is generally assessed by measuring the number of unplanned pregnancies that occur during a specified period of exposure and use of a contraceptive method. The two methods that have been used to measure contraceptive efficacy are the Pearl index and life-table analysis.

Contraceptive failures do occur and for many reasons. Thus, “method effectiveness” and “use effectiveness” have been used to designate efficacy with correct and incorrect use of a method. It is less confusing to simply compare the very best performance (the lowest expected failure rate) with the usual experience (typical failure rate) as noted in the table of failure rates during the first year of use. The lowest expected failure rates are determined in clinical trials, in which the combination of highly motivated subjects and frequent support from the study personnel yields the best results. Contraceptive typical failure rates have been estimated using the data from the 1995 and 2002 U.S. National Survey of Family Growth, correcting for the underreporting of induced abortion.^17,18,20

The 2002 estimates of failure were not significantly different compared with the previous estimates from the 1995 national survey. Women over the age of 30 were less likely to experience failure than young women; teens were more than twice as likely to experience a failure than older women. Hispanic women and even more so, black women, experienced higher failure rates. Groups that were less likely to experience contraceptive failure were women who did not intend to have a subsequent birth and women who had no previous births. Married women experienced the lowest failure rates and cohabiting women the highest. The most important determinants of pill failure, therefore, were: age, intention toward a future birth, parity, and marital status. Interestingly, once these factors were
accounted for, duration of use, race, ethnicity, and poverty status no longer affected the risk of pill failure. The same factors influence condom use, but when corrected for these factors, race, ethnicity, and poverty affected the risk of condom failure.

This is a subject of great interest because the rate of unintended pregnancies in the U.S. continues to be high. About one-half (over 3 million) of all pregnancies in the U.S. are unintended, and in 2002 about 53% of those occurred in women using a method of contraception.^5,13,21 Here is a more striking statistic: one of every two American women aged 15-44 has experienced an unintended pregnancy.¹³

James Blundell proposed in 1823, in lectures at Guy’s Hospital in London, that tubectomy ought to be performed at cesarean section to avoid the need for repeat sections.⁵² He also proposed a technique for sterilization, which he later described so precisely that he must
actually have performed the operation, although he never wrote about it. The first report was published in 1881 by Samuel Lungren of Toledo, Ohio, who ligated the tubes at the time of cesarean section, as Blundell had suggested 58 years earlier.⁵³ The Madlener procedure was devised in Germany in 1910 and reported in 1919. Because of many failures, the Madlener technique was supplanted in the U.S. by the method of Ralph Pomeroy, a prominent physician in Brooklyn, New York. This method, still popular today, was not described to the medical profession by Pomeroy’s associates until 1929, 4 years after Pomeroy’s death. Frederick Irving of the Harvard Medical School described his technique in 1924, and the Uchida method was not reported until 1946.

Few sterilizations were performed until the 1930s when “family planning” was first suggested as an indication for surgical sterilization by Baird in Aberdeen. He required women to be older than 40 and to have had eight or more children. Mathematical formulas of this kind persisted through the 1960s. In 1965, Sir Dugald Baird delivered a remarkable lecture, entitled “The Fifth Freedom,” calling attention to the need to alleviate the fear of unwanted pregnancies and the important role of sterilization.⁵⁴ By the end of the 1960s, sterilization was a popular procedure.

Laparoscopic methods were introduced in the early 1970s. The annual number of vasectomies began to decline, and the number of tubal occlusion operations increased rapidly. By 1973, more sterilization operations were performed for women than for men. This is accurately attributed to dramatic decreases in costs, hospital time, and pain because of the introduction of laparoscopy and minilaparotomy methods. The use of laparoscopy for tubal occlusion increased from only 0.6% of sterilizations in 1970 to more than 35% by 1975.⁵⁵ Since 1975, minilaparotomy, a technique popular in the less developed world, has been increasingly performed in the U.S. These methods have allowed women to undergo sterilization operations at times other than immediately after childbirth or during major surgery.

Laparoscopy and minilaparotomy have led to a profound change in the convenience and cost of sterilization operations for women. In 1970, the average woman stayed in the hospital 6.5 days for a tubal sterilization. By 1975, this had declined to 3 days, and today, women rarely remain in the hospital overnight. The shorter length of stay achieved from 1970 to 1975 represented a savings of more than $200 million yearly in health care costs and a
tremendous increase in convenience for women eager to return to work and their families.⁵⁶ Unlike some advances in technology, laparoscopy and minilaparotomy sterilization are technical innovations that have resulted in large savings in medical care costs.

The great majority of sterilization procedures are accomplished in hospitals by physicians in private practice, but a rapidly increasing proportion is performed outside of hospitals in ambulatory surgical settings, including physicians’ offices. In either hospital or outpatient settings, female sterilization is a very safe operation. Deaths specifically attributed to sterilization now account for a fatality rate of only 1.5 per 100,000 procedures, a mortality rate that is lower than that for childbearing (about 8 per 100,000 births in the U.S.).^57,58 When the risk of pregnancy from contraceptive method failure is taken into account, sterilization is the safest of all contraceptive methods.

Vasectomy has long been more popular in the U.S. than anywhere else in the world, but why don’t more men use it? One explanation is that women have chosen laparoscopic sterilization in increasing numbers. Another is that men have been frightened by reports, often from animal data, of associations with autoimmune diseases, atherosclerosis, and, most recently, prostatic cancer. Large epidemiologic studies have failed to confirm any definite adverse consequences.⁵⁹ When patients consider sterilization, we can assure them that vasectomy has not been demonstrated to have any harmful effects on men’s health.⁶⁰ In addition, vasectomy is less expensive than tubal sterilization, morbidity is less, and mortality is essentially zero.

Serous ovarian cancer, the most common ovarian cancer, originates in the fimbriae of the fallopian tubes.^72,73 and ⁷⁴ Evidence consistently indicates that tubal sterilization is associated with a major reduction in the risk of ovarian cancer.^75,76,77,78 and ⁷⁹ Evidence from the Nurses’ Health Study indicated that tubal sterilization was associated with a 67% reduced risk of ovarian cancer.⁷⁵ In the prospective mortality study conducted by the American Cancer Society, women who had undergone tubal sterilization experienced about a 30% reduction in the risk of fatal ovarian cancer.⁷⁶

If electrons from an electrosurgical generator are concentrated in one location, heat within the tissue increases sharply and desiccates the tissue until resistance is so high that no more current can pass. Unipolar methods of sterilization create a dense area of current under the grasping forceps of the unipolar electrode. To complete the circuit, however, these electrons must spread through the body and be returned to the generator via a return electrode (the ground plate) that has a broad surface to minimize the density of the current to avoid burns as the electrons leave the body. “Unipolar” refers to the method that requires the patient ground plate.

Unipolar electrosurgery can create a unique electrical “capacitance” problem. A capacitor is any device that can hold an electric charge and can exist wherever an insulated material separates two conductors that have different potentials. This property of capacitance explains some of the inadvertent bowel burns that occurred with laparoscopic sterilization.⁸² The operating laparoscope is a hollow metal tube surrounding an active electrode, the forceps used to grasp and coagulate the tubes. When current passes through the active electrode, the laparoscope itself becomes a capacitor. Up to 70% of the current passed through the active electrode can be induced into the laparoscope. If bowel or other structures touch a laparoscope, which is insulated from the abdominal incision (e.g., by a plastic cannula), the stored electrons will be discharged at high density directly into the vital organ. This potential hazard is eliminated by using a metal trocar sleeve rather than a nonconductive sleeve. Because there is little pressure behind the electrons from a low-voltage generator, not enough heat is generated to burn the skin as the capacitance current leaks out into the patient’s body through the metal sleeve. Even if the active electrode comes in direct contact with the laparoscope, as when a two-incision technique is used, the current will leak harmlessly through the metal trocar sleeve. The risk of inadvertent coagulation of bowel or other organs cannot be completely eliminated because all body surfaces offer a path back to the ground plate.

The unipolar electrosurgical technique is straightforward. The isthmic portion of the fallopian tube is grasped and elevated away from the surrounding structures, and the electrical energy is applied until the tissue blanches, swells, and then collapses. The tube is then grasped, moving toward the uterus, recoagulated, and the steps repeated until 2-3 cm of tube have been coagulated. Some surgeons advise against cornual coagulation for fear it may increase the risk of ectopic pregnancy due to fistula formation.

The coagulation and transection technique is performed in a similar fashion with the same instruments. In order to transect the tube, however, an instrument designed to cut tissue must be used. The transection of tissue increases the risk of possible bleeding and does not, by itself, reduce the failure rate over coagulation alone. The specimens obtained by this method are usually coagulated beyond microscopic recognition and, therefore, will not provide pathologic evidence of successful sterilization.

The bipolar method of sterilization eliminates the ground plate required for unipolar electrosurgery and uses a specially designed forceps. One jaw of the forceps is the active electrode, and the other jaw is the ground electrode. Current density is great at the point of forceps contact with tissue, and the use of a low-voltage, high-frequency current prevents the spread of electrons. By eliminating the return electrode, the chance of an aberrant pathway through bowel or other structures is greatly reduced. There is, however, a disadvantage with this technique. Because electron spread is decreased, more applications of the grasping forceps are necessary to coagulate the same length of tube than with unipolar coagulation. As desiccation occurs at the point of high current density, tissue resistance increases, and the coagulated area eventually provides resistance to flow of the low-voltage current. Should the resistance increase beyond the voltage’s capability to push electrons through the tissue, incomplete coagulation of the endosalpinx can result.⁸³ Bipolar coagulation is very effective only if three or more sites are coagulated on each tube.⁸⁴

Bipolar cautery is safer than unipolar cautery with regard to burns of abdominal organs, but most studies indicate higher failure rates. Although the bipolar forceps will not burn tissues that are not actually grasped, care must be taken to avoid coagulating structures adherent to the tubes. For example, the ureter can be damaged when the tube is adherent to the pelvic side wall.

Female sterilization by mechanical occlusion eliminates the safety concerns with electrosurgery. However, mechanical devices are subject to flaws in material, defects in manufacturing, and errors in design, all of which can alter efficacy. Three mechanical devices have been widely used and have low failure rates with long-term follow-up: the Hulka-Clemens (spring) clip, the Filshie Clip, and the silastic (Falope or Yoon) ring. Each of the three requires an understanding of its mechanical function, a working knowledge of the intricate applicator necessary to apply the device, meticulous attention to maintenance of the applicators, and skillful tubal placement. These devices are less effective when used immediately postpartum on dilated tubes.

Tubal ligation, accomplished through a small suprapubic incision, minilaparotomy, is the most frequent method of interval female sterilization around the world. In the U.S. and most of the developed world, laparoscopy is more popular, but minilaparotomy is gaining in favor because of its safety, simplicity, and adaptability to ambulatory surgical settings (particularly when local anesthesia is used).^86,87

The fallopian tubes can be occluded through the minilaparotomy incision with bands or clips, but a simple Pomeroy tubal ligation is the method most commonly used. Patient characteristics, such as obesity, previous pelvic infection, or previous surgery, are the principal determinants of complications.⁸⁸

Minilaparotomy is accomplished through an incision that usually measures 2-4 cm in length. Tubal ligation through a suprapubic incision can be accomplished for obese patients, but the incision will necessarily exceed the usual length. Forceful retraction increases the pain associated with the procedure and the time of recovery. For these reasons, we believe that minilaparotomy for ambulatory tubal occlusion should be limited to patients who are not obese (usually less than 150-160 lb, 70 kg).

Tubal occlusion is difficult to accomplish through a minilaparotomy if the uterus is immobile. Laparoscopic tubal occlusion, on the other hand, does not require extreme uterine elevation or rotation and is a better choice for a patient with a uterus fixed in position.