Sterilization: Long-Term Issues

Adopted by more than 180 million women worldwide, female sterilization ranks as one of the more popular contraceptive methods.¹ Globally and in the United States, female sterilization is 2.5- to 4-times more prevalent than male sterilization.^1,2 Until recently, medically preferred, tubal sterilization techniques required a transabdominal approach. Since 2000, the Essure transcervical method of tubal sterilization has been approved in Australia, Singapore, parts of Europe, Canada, and the United States. Sterilization differs from other methods of contraception because it is meant to be permanent. This permanence, along with the fact that this elective procedure is usually performed in healthy women of reproductive age, raises several issues. Among them are issues surrounding the decision-making process and the incidence of long-term side effects. This chapter focuses on current evidence about regret about sterilization and sterilization failure. It also addresses the influence of sterilization on other aspects of women's health. These include menstrual cycle changes, cancer incidence, hysterectomy, bone density, the risk of sexually transmitted disease, sexuality, and preventive care. Although long-term data about Essure transcervical sterilization do not exist, there is no reason to believe that issues of regret, influence of the procedure on future health and counseling regarding permanence should be any different than what is seen or expected with transabdominal approaches to sterilization. This chapter discusses the topics listed here in light of how to best counsel and support patients throughout their decision-making process.

Cohort, case control, and descriptive studies indicate that most women who have undergone sterilization do not regret it.^3,4,5,6,7,8 Although reassuring, this finding does not negate regret's importance when it does arise. Depending on the design of the study undergoing consideration, the percentages of women who express regret has ranged from .9% to 26%. Many of these studies reported any occurrence of regret; few measured its significance or persistence. In some studies, a woman's seeking reversal of the sterilization procedure was used as a proxy for the significance of her regret. Using this proxy, researchers who analyzed the 1982 National Survey of Family Growth found that although 26% of sterilized women said that they wanted more children, only 10% wanted to reverse the procedure. This shows how complex it is for researchers to determine the significance of a woman's regret.

Researchers have tried to isolate patient characteristics associated with subsequent regret. Factors often associated with regret after sterilization include a woman's being young at the time of the procedure and her experience of unforeseen life events (e.g., a new spouse or a child's death).^5,8 In most studies, the strongest predictor of regret is sterilization occurring at age 30 or younger. In the United States Collaborative Review of Sterilization (CREST), the cumulative probability of regret within 14 years after tubal sterilization was 20.3% for women age 30 or younger at the time of the procedure, and 5.9% for women older than age 30.⁵ In addition, regret arises more often among women who chose sterilization under pressure from a partner or health care provider. It is also more likely to trouble women who had poor communication or conflicts with their partner during the decision-making process. Women who underwent sterilization solely for a medical indication are also more likely to feel regret.^{5,6,7,8,9,10,11,12,13,14}

Contrary to popular belief, several studies report that the number of children a woman has does not correlate with regret. The CREST found that nulliparous women are no more likely to experience regret than multiparous women. The data are unclear on the question of whether women are more likely to experience regret if the sterilization is performed immediately after vaginal delivery or concurrent with cesarean section.^{5,8,9,10,15,16,17,18,19,20} Furthermore, data have consistently shown that women are not more likely to experience regret when sterilization is performed along with an induced abortion.^9,20,21,22

Risk factors cannot reliably predict which women will regret the procedure. As indicated by CREST findings, while the probability of regret was greatest in younger women, 80% of these young women experienced no regret 14 years postprocedure. For these reasons, no woman should be denied sterilization as long as she has considered the procedure's impact on her current life and on her life as it might be if her circumstances change greatly. Faced with a woman characterized by one of the factors listed as being associated with regret, most clinicians encourage her to think about her full range of contraceptive options, yet they will not deny her the procedure. This course of action is prudent, ethical, and appropriate.

The antithesis of regret after sterilization is failure of the procedure. Sterilization failure is a rare complication that may occur many years after the procedure was performed. For transabdominal approaches, historically reported failure rates of 3 to 4 failures per 1000 procedures in the first year after the operation and 1 failure per 1000 procedures in subsequent years were based on data limited to the first 2 years after surgery.^23,24,25 More current data reveal that failure rates are higher than originally thought among women 2 or more years after sterilization.^26,27 Researchers in Thailand have reported an 8-year failure rate of 1.5%. Consistent with this Thai statistic, the United States-based CREST study reported a 10-year cumulative failure rate of 1.85% for all sterilization methods.^26,27 CREST's cumulative rate of 1.85% represents a summary figure encompassing the rates for many different occlusive methods. The 10-year cumulative failure rates range from a low of .75% for unipolar coagulation and postpartum partial salpingectomy to a high of 3.65% for spring clip application.²⁷ Because it has been in use for only a few years, long-term failure rates are not available for the Essure transcervical method of sterilization.

Another transcervical approach that is clouded in political and scientific controversy is the quinacrine method of sterilization. In parts of the developing world, tens of thousands of women underwent quinacrine sterilization in the 1990s. This method is currently undergoing carcinogenicity and mutagenicity testing in the United States. Retrospective studies of women sterilized with quinacrine in Viet Nam reveal a 5-year failure rate of 12.6 per 100 women receiving two insertions. The 5-year failure rate decreases to 6.8 per 100 women in women age 35 and older at the time of sterilization.²⁸

Although the CREST data emerge from one of the longest, largest, cohort studies of transabdominal female sterilization to date, one must use caution before extrapolating these data to all situations. The CREST Study was conducted in teaching institutions, and no information is given regarding operator experience. Data have consistently shown that female sterilization is highly effective, regardless of the occlusive technique used, when performed by experienced operators using proper technique and appropriately selected patients.^{24,27,28,29,30,31} A reanalysis of the unexpectedly high failure rate for bipolar coagulation showed that the 5-year cumulative failure rate for procedures performed early in the study, when this laparoscopic technique was fairly new, was 1.95%. This rate is three-times higher (1.95% vs. .62%) than the failure rate for procedures performed later in the study.²⁷ Moreover, 5-year cumulative failure rates were much lower if each tube was coagulated at three or more sites, rather than one or two sites (.32% vs. 1.29%). This .32% statistic is not statistically different from the rate reported for unipolar coagulation (.23%) during the same time period.³²

Reasons for sterilization failure include undetected preexisting pregnancy (luteal phase pregnancy), occlusion of the wrong structure, incomplete or inadequate occlusion, slippage of a mechanical device, development of a tuboperitoneal fistula, and spontaneous reanastomosis or recanalization of the previously separated tubal segments.^{33,34,35,36,37} If the wrong structure is occluded, it is commonly the round ligament. When sterilization failures occur with the use of rings and clips, incorrect positioning of the device relative to the tube is commonly identified as the cause.^{24,28,29,36,38} With failures after bipolar cautery, incomplete destruction of an adequate length of tube is the usual cause.^35,39

When sterilization failure occurs, the pregnancy is more likely to be ectopic than it would be in a woman who has not been using contraception and becomes pregnant. In the CREST study, of the 143 pregnancies that occurred after failed sterilization, one-third were ectopic.⁴⁰ This level far exceeds the .05% ectopic pregnancies that can be expected among women using no contraception who become pregnant. CREST data further showed that the proportion of ectopic pregnancies was three-times greater 4 or more years after sterilization, compared with failures occurring during the first 3 years after the procedure.

The overall risk of pregnancy is low among sterilized women. Therefore, the absolute risk of ectopic pregnancy among them is substantially lower than the absolute risk of ectopic pregnancy among women not using contraception or those using intrauterine devices (IUDs).^{35,40,41,42,43,44,45} By analyzing case-control data, Holt and colleagues found that women undergoing interval sterilization had .8-times (range: .4 to 1.7) the risk of ectopic pregnancy of current IUD users, and .2-times (range: .1 to .3) the risk of women using no contraception.⁴¹

Since the 1950s, researchers have published work debating whether significant menstrual changes occur after tubal sterilization. Researchers, prompted by subjective reports and retrospective studies, have postulated that tubal occlusion may cause menstrual changes through various mechanisms. Among them are: (1) interruption and reduction of blood supply to the ovaries. This could cause ovarian dysfunction and alter the ovaries' production and/or release of estrogen and progesterone; (2) interference with the direct diffusion of estrogen and progesterone from the ovaries to the uterus, leading to endometrial malfunction; (3) interference with the prostaglandin feedback mechanism between the uterus and ovary with deficient prostaglandin production and disturbances in ovarian steroidogenesis; and (4) uterine vascular congestion.

These cited hypotheses rest on the premise that tubal occlusion causes a clinically significant interruption of mesosalpingeal and broad ligament vessels. On theoretical grounds alone, such theories arouse suspicion. Two thirds of the ovarian blood supply comes from the uterine artery, through the tubal artery, and one-third is from the ovarian artery. Given that the anastomotic network between the tubal and ovarian arteries is extensive, it is unlikely that interruption of one of these arteries would result in clinically remarkable reduction in blood flow to the ovaries.⁴⁶ Investigations designed to gauge ovarian hormonal patterns after sterilization have yielded conflicting results. These results, though, remain largely within the vast range of normal values.^47,48,49

Early cohort and case control studies that reported menstrual function after tubal sterilization often failed to control for confounding factors. Among such confounding factors are previous contraceptive use, previous menstrual pattern, and advancing age, all of which can affect menstrual patterns.^{33,50,51,52,53} Many early studies also failed to control systematically for other potential confounding variables such as pre-existing gynecologic disorders, parity, and recall bias.^{33,50,51,52,53} Depending on the study, there were also problems with study design and implementation. These problems included a high percentage of participants lost to follow-up, inappropriate controls, and vague definitions.

Most cohort studies that controlled for previous menstrual history, previous contraception, or increasing age showed no significant menstrual changes after sterilization.^{54,55,56,57,58} This finding remains unchanged when the data are analyzed by the method of tubal occlusion used. Although earlier studies had indicated that menstrual cycle changes were more commonly associated with unipolar coagulation, more recent ones have found no association with a particular method of occlusion.^23,59,60,61

There is less clarity in the data from studies that followed-up women for more than 2 years. Of four prospective studies that followed-up women for 4.5 to 6 years, two report menstrual function changes, whereas two report none.^19,62,63,64 Studies of more objective measures of ovarian function, rather than recall, do not show any consistent changes in progesterone or estrogen levels. Furthermore, studies that objectively measured presterilization and poststerilization menstrual blood loss showed no significant difference before and after the procedure.^46,49,65

Menstrual histories of more than 9000 women sterilized during the CREST study and more than 566 women whose partners underwent vasectomy during the same time period were analyzed to determine whether there might be a causal association between sterilization and menstrual changes.⁶⁶ Women who had undergone sterilization were more likely to have experienced decreases in amount of bleeding, the number of days of bleeding and the amount of menstrual pain, but an increase in cycle irregularity. These changes, which tend to be inconsistent with other studies that suggested menstrual cycle changes after sterilization, were attributed to chance statistical significance based on the multiple comparisons made during analysis or to unmeasured differences between the two groups of women. The authors concluded that the most likely explanation for menstrual cycle changes seen after sterilization is coincidental association, because tubal sterilization and menstrual abnormalities are both common events.⁶⁶

Many cohort or case-control studies that report on future risk of hysterectomy among sterilized women have shown relative risks that range from 1.3 to 4.4.^{50,67,68,69,70,71,72} However, researchers have found no direct physiologic cause for such heightened risk. Furthermore, other studies have indicated no increase in the risk of hysterectomy or have shown reduced risk.^25,72,73 In those studies that have shown increased risk, the increase has been observed in women who were younger than age 30 to 35 years at the time of their sterilization.^{48,67,68,70,72} One nonbiologic explanation that some have proposed to explain observations of increased hysterectomy risk is that physicians who perform sterilization and women who choose it have a leaning toward surgical intervention. Some theorize, too, that nonsterilized women may avoid hysterectomy as a solution to gynecologic disorders, either because they wish to avoid surgery or because they wish to remain fertile.^48,72 Another noncausal explanation theorizes that sterilization may be a response to a history of previous adverse obstetric and gynecologic events; Santow and Bracher have correlated sterilization and hysterectomy with IUD removal secondary to side effects and with multiple fetal losses.⁷³

Recently, there have been published case series of women who have had a tubal sterilization in the past, who subsequently undergo rollerball endometrial ablation or endometrial resection for treatment of menorrhagia, and who later have cyclic severe cramping pain, thought secondary to trapped endometrial tissue, resulting in hematosalpinges or endometriosis in the proximal segment of the fallopian tube.^74,75,76 In search for risk factors for hysterectomy after rollerball endometrial ablation, Mall and associates conducted a case-control study that indicated a statistically significant association between previous tubal ligation and hysterectomy. In this study, 15 of 21 subsequent hysterectomies occurred among women with a previous tubal ligation. Reasons for the hysterectomy (menorrhagia alone vs. menorrhagia and pelvic pain vs. pain only) were not statistically different between the two groups of women. Of the 15 pathology reports reviewed, three had evidence of trapped endometrial tissue or proximal tubal dilatation.⁷⁷ Whether a postablation tubal sterilization syndrome with associated risk of hysterectomy really exists will require additional studies.

Few studies have addressed the influence of sterilization on the incidence of breast cancer, endometrial cancer, or bone mineral density. The Cancer and Steroid Hormone Study involved 4742 women in a case-control study that found no association between sterilization and breast cancer.⁷⁹ Case-control studies report no increase in relative risk for endometrial cancer,^80,81 nor have statistically significant relationships between bone mineral density and sterilization been reported.⁸²

Many cohort and case-control studies have reported a protective effect of sterilization against ovarian cancer that prevails during the first 15 years after the procedure.^{83,84,85,86,87,88,89,90} Researchers hypothesize that this protection results from the ovaries' reduced exposure to inert or infectious causes or to promoters of malignant transformation.^84,88,91 Although researchers have yet to pinpoint a biologic mechanism, the consistency of the finding of reduced ovarian cancer risk across studies supports the validity of this observation.

Although sterilization does not protect women from acquiring sexually transmitted infections, it does protect them against pelvic inflammatory disease. It does so by limiting the spread of organisms from the lower genital tract to the peritoneal cavity.^{25,92,93,94,95} The protection, however, is not complete. There have been rare reports of pelvic inflammatory disease and tuboovarian abscess, diagnosed soon after the procedure and many years later.^93,96,97,98

Although retrospective studies have reported both improvement and deterioration of sexuality after sterilization,^{6,99,100,101,102} most prospective studies show neither effect. Prospective studies have generally reported no change or improvements in sexual function, sexual desire, sexual satisfaction, coital frequency, and self-perceived femininity.^{6,102,103,104,105}

Data suggest that sterilized women in the United States are less likely to return for annual screening than women who use reversible contraception.^106,107 In addition, researchers have discovered that the sexual partners of sterilized women use condoms less often than those of other women.^106,107

Female sterilization is a safe and minor operation. On balance, it entails few risks and substantial benefits for a couple or a woman when they have no further desire to bear children. Primary sources of discontent result from the procedure's failure, regret over having had it performed, and subsequent health changes that are attributed to sterilization. Physicians can help to minimize such discontent through their competent performance of the procedure and by taking measures to ensure that women reach this important decision only after careful thought.

For a woman or a couple to reach a deliberate, informed decision regarding female sterilization, certain conditions must prevail. The woman (or couple) needs to know about the options among reversible contraceptives and about vasectomy. They must also understand the intended irreversibility of the procedure. She must understand how the sterilization will be performed, the type of anesthesia to be used, and the operative risks. She must also understand that if she experiences the rare complication of pregnancy after the procedure, she must seek a prompt evaluation because of her heightened risk for an ectopic pregnancy.

A woman considering sterilization also needs to think about the chances that her life situation will change. She needs to have decided that any such change will not alter her satisfaction with having had the procedure. She needs to have consulted all the individuals with whom she wants to confer and to feel comfortable proceeding in the light of these conversations. She must recognize that although no one can predict her future health status with certainty, research data indicate that she will not be at heightened risk for an illness just because she has been sterilized.

Because anyone's future health is unpredictable and because protection against ovarian cancer and upper genital tract infections that sterilization confers is only partial, she needs to realize that she will still need regular preventive care, including pelvic examinations. As importantly, she needs to recognize that sterilization does not protect against sexually transmitted infections, including HIV, so condom use for STI prevention is as important after sterilization as it is with reversible methods of contraception. It is encouraging that after such messages, researchers at Baylor found an increase in intended condom use of 32% to 51% of women undergoing sterilization.¹⁰⁸

She should understand that tubal sterilization does not protect against disorders that may require hysterectomy. Some women who have undergone tubal sterilization eventually do, in fact, have disorders that prompt hysterectomy. These disorders would have occurred whether or not the sterilization had taken place.

Based on current data, the woman who chooses sterilization may be more prone to decide on a hysterectomy at a future date. Most people think that this finding reflects that women who have experienced one successful surgical solution may be more amenable to surgery than women who have not opted to be sterilized. The woman considering sterilization should know that there is no conclusive evidence that the operation will change her menstrual pattern or any pain associated with menstruation. If, however, she has been using hormonal contraception or an intrauterine device up until the time of her sterilization, she may experience a change in the timing, blood loss, or pain associated with menses. These kinds of changes arise because of the discontinuation of the previous method, not because of the sterilization.

The level of understanding described in the preceding paragraphs does not occur in a 30- to 60-minute clinical session. As with any irreversible decision, a woman's choice of sterilization warrants careful consideration over time. Some women have received enough information to have thoughtfully reached their decision before entering the clinician's office. Others receive exposure to the idea of sterilization for the first time when they meet with their health care provider. Most know something about the procedure but grow in their understanding after they consult with this provider. The provider must speak with each woman to figure out what she knows of the vast continuum of knowledge needed to reach this decision. Only with this understanding of each woman interested in sterilization will the provider be able to fully serve the individual as she weighs her choices.