CONTRACEPTION. reversal

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1 CONTRACEPTION FERTILITY AND STERILITY VOL. 74, NO. 5, NOVEMBER 2000 Copyright 2000 American Society for Reproductive Medicine Published by Elsevier Science Inc. Printed on acid-free paper in U.S.A. Requesting information about and obtaining reversal after tubal sterilization: findings from the U.S. Collaborative Review of Sterilization Johannes E. Schmidt, M.D., M.P.H., a,b Susan D. Hillis, Ph.D., b Polly A. Marchbanks, Ph.D., b Gary Jeng, Ph.D., b and Herbert B. Peterson, M.D., b for the U.S. Collaborative Review of Sterilization Working Group Received November 12, 1999; accepted May 11, Presented at the 48th Annual EIS Conference, CDC, Atlanta, Georgia, April 19 23, 1999 and at the XV Meeting of the International Epidemiological Association (IEA) Florence, Italy, August 31 September 3, Supported by an interagency agreement with the National Institute of Child Health and Human Development ( HD ). Reprint requests: Susan D. Hillis, Ph.D., DRH/NCCDPHP (MS K-34), Centers for Disease Control and Prevention, 4770, Buford Highway, N.E., Atlanta, Georgia (FAX: ; seh0@cdc.goc). a Epidemic Intelligence Service (EIS), Division of Applied Public Health Training, Epidemiology Program Office, Centers for Disease Control and Prevention. b Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention /00/$20.00 PII S (00) Centers for Disease Control and Prevention, Atlanta, Georgia; The U.S. Collaborative Review of Sterilization Working Group includes Herbert B. Peterson, M.D., Joyce M. Hughes, Zhisen Xia, Ph.D., Lynne S. Wilcox, M.D., and Lisa Ratliff Tylor, Atlanta, Georgia; James Trussel, Ph.D., Princeton, New Jersey; Norman G. Courey, M.D., C. M., Buffalo, New York; Philip D. Darney, M.D., M.Sc., San Francisco, California; Ernst R. Friedrich, M.D., St. Louis, Missouri; Ralph W. Hale, M.D., Washington, D.C.; Roy T. Nakayama, M.D., Honolulu, Hawaii; Jaroslav F. Hulka, M.D., Chapel Hill, North Carolina; Alfred N. Poindexter, M.D., Houston, Texas; George M. Ryan, M.D. and Frank Ling, M.D., Memphis, Tennessee; Gary K. Stewart, M.D., Sacramento, California; and Howard A. Zacur, M.D., Baltimore, Maryland Objective: To determine the cumulative probabilities over 14 y of requesting information on sterilization reversal and of obtaining a reversal and to identify risk factors observable at sterilization for both measures of regret. Design: The U.S. Collaborative Review of Sterilization, a prospective cohort study. Setting: Fifteen medical centers in 9 cities. Patient(s): 11,232 women. Main Outcome Measure(s): Cumulative probabilities of requesting information on reversal and undergoing reversal. Result(s): The 14-y cumulative probability of requesting reversal information was 14.3% (95% confidence interval [CI], 12.4% 16.3%). Among women aged 18 to 24 y at sterilization, the cumulative probability was 40.4% (95% CI, 31.6% 49.2%). Women aged 18 to 24 y were almost 4 times as likely to request reversal information as were women 30 years of age (adjusted rate ratio [RR], 3.5; 95% CI, ). Number of living children was not associated with requesting reversal information. The overall cumulative probability of obtaining reversal was 1.1% (95% CI, ). Younger women (18 to 30 y) were more likely to obtain reversal (RR, 7.6; 95% CI, ). Conclusion(s): Women who were sterilized at a young age had a high chance of later requesting information about reversal, regardless of their number of living children. (Fertil Steril 2000;74: by American Society for Reproductive Medicine.) Key Words: Tubal sterilization, poststerilization regret, request for reversal information, obtaining sterilization reversal Tubal sterilization is the most prevalent method of birth control in the United States. More than 600,000 U.S. women choose this procedure every year. By 1995, 10 million women had undergone tubal sterilization (1). In spite of the popularity of this method, evidence suggests that some women may regret their decision during ensuing years. Previous studies have identified 3 measurable outcomes of poststerilization regret that may reflect the intensity of regret: first, selfreported regret; second, request for information about sterilization reversal; and third, actually obtaining reversal surgery (2 7). Because of the popularity of tubal sterilization in the United States, a large number of sterilized women may potentially be affected by some degree of regret. Using preliminary data from the U.S. Collaborative Review of Sterilization (CREST), Grubb et al. (3) reported in 1985 that 892

2 2.7% regretted having had a tubal sterilization at 2 y after the procedure, and Wilcox et al. (4) later found that 6.2% of CREST enrollees had requested information regarding reversal (0.2% actually obtained reversal surgery) at 5 y after sterilization. Recently, Hillis et al. (5), using data from the completed study (follow-up for CREST ended in 1994), found the 14-y cumulative probability of self-reported regret to be 12.7%. In the present analysis, we use data from the completed CREST study to describe 2 of the aforementioned indicators of regret: requesting information about sterilization reversal and actually obtaining a sterilization reversal. This analysis has 2 objectives: 1) to examine the cumulative probabilities at the 14-y follow-up of women s requesting information on sterilization reversal and obtaining such a reversal and 2) to identify independent predictors for requesting information on and obtaining reversal that are identifiable before sterilization. MATERIALS AND METHODS The methods of this study have been described elsewhere in detail (7 9). The study population was selected from women participating in the U.S. CREST, a multicenter prospective cohort study. CREST is the largest and longest study of women undergoing tubal sterilization in the United States. Participating centers were located in Baltimore, MD; Buffalo, NY; Chapel Hill, NC; Honolulu, HI; Houston, TX; Memphis, TN; Sacramento, CA; San Francisco, CA; and St. Louis, MO. CREST was approved by the institutional review board in each center. From 1978 to 1987, women aged 18 to 44 y who underwent tubal sterilization in participating centers were approached for enrollment. Before the procedure, trained nurse interviewers used pretested standardized questionnaires to obtain a detailed history from each woman who agreed to participate. We intended to follow all participants after sterilization by telephone interviews annually for 5 y. Women who had been enrolled between 1978 and 1983 were eligible to provide 1 final interview 8 to 14 y after sterilization. Study Population and Outcome Measures Women were eligible for inclusion in our analysis if they 1) were 18 to 44 y of age at sterilization; 2) had completed at least 1 follow-up interview; 3) had a postpartum sterilization after either vaginal delivery or cesarean section, an interval sterilization (i.e., performed while they were not recently pregnant), or a sterilization immediately after elective abortion; and 4) had provided complete information regarding regret subsequent to tubal sterilization. Initially, a total of 11,232 women met the eligibility criteria. At each follow-up interview, participants were asked whether they had requested information about sterilization reversal or whether they had actually obtained tubal reversal. Women who answered yes to the question, Since you were last interviewed, have you asked any doctors or other people about having your tubes rejoined so you can become pregnant? were classified as having requested information on reversal. Subsequently, the following question was used to ascertain whether participants had actually obtained a reversal: Since your last CREST tubal sterilization, or last follow-up, have you had a tubal anastomosis? Obtaining sterilization reversal through tubal anastomosis refers to a woman undergoing surgery for tubal repair. In addition, we tried to validate the requesting of information as a measure of regret by asking a subset of women who answered yes to the first question whether they had actually requested the procedure. Statistical Analysis We considered demographic, reproductive, and clinical factors that may have influenced the risk of requesting information about sterilization reversal. Pertinent information was obtained during standardized presterilization interviews and thus exclusively reflects the woman s status at the time of her sterilization. Using actuarial life table analysis, we calculated separately the 14-y cumulative probability of either requesting reversal information or of obtaining reversal. In life table analysis, cumulative probability is the corresponding frequency measure used to describe the risk at any given point during follow-up that the outcome measure will occur (10). We then calculated unadjusted hazard ratios to examine whether the 14-y cumulative probabilities of either requesting information on reversal or actually obtaining reversal were increased among any subgroup of participants. All variables that were significantly associated with an increased probability of requesting reversal information or of obtaining reversal were included in a multivariate Cox proportional hazards model to identify independent risk factors. Potential predictors included age (categorical), race (white or nonwhite), education ( 12, 13 16, or 17 y), marital status (married or unmarried), history of induced abortion (none or 1 abortions), and time between sterilization and birth of the youngest child. Each of these variables satisfied the proportionality assumption. We considered number of living children only for women with interval sterilizations because the data were incomplete for women who underwent postpartum procedures. Because previous studies indicate that young age at sterilization is associated with an increased risk of poststerilization regret, we also conducted an age-stratified analysis to identify any subgroup of young women who were at increased risk of either requesting information regarding reversal or obtaining reversal. Generally, a woman was considered to be at risk for either event until the interview date when she acknowledged that she had requested reversal information or had obtained reversal. For women for whom neither event had occurred, follow-up time was considered the time until the last interview data. Follow-up was discontinued if a woman experienced 1 of the following major events: hysterectomy, repeat tubal sterilization, pregnancy, or death. Statistical FERTILITY & STERILITY 893

3 TABLE 1 Study population (N 11,232) characteristics at sterilization. Characteristic N % , , White 6, Black 3, Other 1, Marital status Unmarried 3, Married 7, History of induced abortion a No 8, Yes 2, Medicaid enrollment a No 6, Yes 2, Time between tubal sterilization and birth of youngest child a Postpartum 1, Interval 8, a Sample size decreased because of missing data. significance was assumed when the confidence intervals for the hazard ratios did not include the null value of RESULTS The study cohort was racially diverse; half the participants were aged 30 years, and about two thirds were married (Table 1). Twenty-three percent had a history of one or more induced abortions. Twenty-seven percent stated that they were currently enrolled in Medicaid. Most of the women had undergone sterilization during an interval period, as opposed to the postpartum period. Among women eligible for the interview, at 1, 3, 5, and 8 to 14 y after tubal sterilization, 93%, 84%, 75%, and 57%, respectively, were interviewed. Women who were aged 30, nonwhite women, and married women were more likely to be lost at 8 to 14 years of follow-up than were women older than 30 years, white women, and unmarried women (data not shown). The overall cumulative probability of requesting information on sterilization reversal at the 14-y of follow-up was 14.3% (95% CI, 12.4% 16.3%; Table 2); a total of 698 women requested such information. The probability estimates varied substantially among subgroups as defined by selected demographic and obstetric characteristics present at the time of sterilization. We observed a clear gradient in the association between age at sterilization and the long-term risk of requesting information on sterilization reversal. The cumulative probability of requesting such information increased dramatically with decreasing age at sterilization. Women 18 to 24 years of age at sterilization had a cumulative probability of 40.4% (95% CI, 31.6% 49.2%). Among women aged 25 to 30 y and 31 to 35 y, the cumulative probabilities were 15.6% (95% CI, 12.6% 18.7%) and 8.2% (95% CI, 5.5% 10.9%), respectively. Women whose age at sterilization was 35 years had the lowest probability (4.4%; 95% CI, 1.9% 7.0%), strengthening the inverse relationship between age at sterilization and long-term risk of request for information on reversal (Fig. 1). We also found that women of nonwhite race, women with 12 years of formal education, unmarried women, women with a history of 1 induced abortions, and women who TABLE 2 14-y cumulative probability (%) of requesting information on reversal, overall and by selected characteristics at sterilization. Characteristic Cumulative probability a 95% Confidence interval Overall Black White Other Education (y) Marital status Married Unmarried History of induced abortion None Medicaid enrollment No Yes Time between tubal sterilization and birth of youngest child Postpartum After vaginal delivery After cesarean section Interval b 15 d 1 y y y y No previous pregnancies a Cumulative probability per 100 procedures. b Time coded as follows: 15 d 1 y d; 2 3 y d; 4 7 y d; 8 y 2555 d. 894 Schmidt et al. Poststerilization reversal information requests Vol. 74, No. 5, November 2000

4 FIGURE 1 Cumulative probability (per 100 procedures) of requesting information on reversal by age at sterilization and year of follow-up. underwent sterilization immediately following vaginal delivery or within 3yofthebirth of the youngest child had a higher 14-year cumulative probability of requesting information regarding reversal (Table 2). Among women who underwent interval sterilization, those who did so within 1 y after the birth of the youngest child were no more likely to request information about reversal than were women whose procedures were performed 2 to 3 y after the birth of the youngest child. Within the interval group, women who underwent sterilization 8 y after the birth of the youngest child and women who had never borne children had the lowest probabilities of requesting information. The results of the age-stratified analysis revealed an even higher risk of poststerilization requests for reversal information among certain subgroups. Almost half of the women who at the time of sterilization were both young (18 24 y) and unmarried requested reversal information at some point during follow-up (49.2%; 95% CI, 35.1% 63.2%). Similarly, young, nonwhite women had a higher probability of requesting reversal information (48.1%; 95% CI, 36.1% 60.1%) than did white women of similar age (30.5%; 95% CI, 17.9% 43.1%). After adjustment for potential confounders, young women (18 to 24 y old at sterilization) were almost 4 times as likely to request reversal information as were women aged 30 years (adjusted rate ratio [RR] 3.5; 95% CI, ; Table 3). Women aged 25 to 30 y were still more than twice as likely to request reversal information than were those in the referent group (RR, 2.2; 95% CI, ). Significant but weaker associations were found for nonwhite race and a history of 1 abortions. In addition, women who had their sterilization performed immediately after vaginal delivery or within 7 y after the birth of the youngest child were significantly more likely to request reversal information than were women sterilized at 8 or more y after the birth of the youngest child. For women who were sterilized on an interval basis, no association was found between the number of living children and requests for information about reversal (data not shown; unadjusted RR, 1.0; 95% CI, ). Medicaid enrollment status was not included in the final model because of the large amount of missing data (24.4%). However, we did evaluate an adjusted model for the reduced sample that included Medicaid enrollment status, age, race, level of education, marital status, history of induced abortion, and timing between sterilization and birth of the youngest child, and we found that Medicaid enrollees had a mildly elevated probability of requesting reversal information (adjusted RR, 1.3; 95% CI, ). Further analysis, however, revealed a strong correlation between Medicaid enrollment and nonwhite race (75% of those enrolled in Medicaid were of minority race), suggesting that Medicaid enrollment may be a surrogate measure for racial origin (data not shown). Medicaid enrollment was not associated with actually obtaining reversal. The overall cumulative probability of actually obtaining TABLE 3 Adjusted rate ratios (RR) for request for reversal information. Characteristic Adjusted RR a 95% Confidence intervals Referent Nonwhite White Referent History of induced abortion Yes No Referent Time between tubal sterilization and birth of youngest child Postpartum After vaginal delivery After cesarean section Interval b 15 d 1 y y y y/no previous pregnancies Referent a Each variable simultaneously adjusted for all variables significant in unadjusted analyses. b Time coded as follows: 15 d 1 y d; 2 3 y d; 4 7 y d; 8 y 2555 d. FERTILITY & STERILITY 895

5 TABLE 4 14-y cumulative probability (%) of women obtaining tubal reversal by selected characteristics at sterilization. Characteristic Cumulative probability a 95% Confidence intervals Overall Black White Other Marital status Married Unmarried Time between tubal sterilization and birth of youngest child Postpartum After vaginal delivery After cesarean section Interval a Cumulative probability per 100 procedures. reversal surgery (1.1%; 95% CI, 0.5% 1.6%) was much lower than that for requesting information about reversal (Table 4). Because of the small number of women who obtained reversal, we considered a reduced number of categories for the variables age and time between sterilization and birth of the youngest child. We found that women aged 30 y had a higher probability of obtaining reversal than did women aged 30 y. In addition, women who had undergone interval sterilization had a higher probability of obtaining reversal than those who had undergone a postpartum procedure. Multivariate analysis of risk factors for obtaining a reversal again revealed a strong age gradient (data not shown): younger women (18 30 y) were almost 8 times as likely to obtain the reversal procedure as were older women (RR, 7.6; 95% CI, ). A subset of women (n 214) who had sought information regarding reversal were also asked whether they had actually requested that their sterilization be reversed. Although more than half of the 214 women who had sought reversal information had also requested the reversal procedure (57% n 121), only a small number of women (n 38) actually obtained a reversal. We also have limited information on the reason for not obtaining reversal. Among a subgroup of women enrolled in later years of the study (n 110), 50% (n 55) reported that financial hardship was the reason they did not have a reversal procedure. Thirtyfour percent (n 37) indicated other reasons for not obtaining the procedure. DISCUSSION We found that the cumulative probability of requesting information regarding sterilization reversal was high among women sterilized at a young age. Young age was the strongest predictor identifiable at the time of sterilization for both requesting reversal information and actually obtaining reversal. The 14-y cumulative probability of requesting reversal information among young women was 40% and decreased with increasing age at the time of sterilization. Among young women who either were unmarried at sterilization or were of nonwhite race, the probability of requesting reversal information approached 50%. Overall, the percentage of women who actually obtained reversal surgery was quite small. Using a large, prospective, multicenter cohort design, we found a higher long-term cumulative probability of requesting reversal information than has been demonstrated by previous cross-sectional reports, many of which do not specify whether measures of poststerilization regret were long term or short term. According to the 1995 National Survey of Family Growth, for example, 10% of sterilized American women 15 to 44 y of age and 26% of those aged 15 to 24 y at the time of the interview expressed the desire for reversal (1). In another cross-sectional study among 497 sterilized women aged 25 to 44 y and living in metropolitan Montreal, Canada, Marcil-Gratton (11) found that 4% had discussed with a physician their desire to restore fertility, and 1% had requested reversal. In a survey among 2,134 Swedish women who had undergone sterilization 5 to 11 y earlier, Platz- Christensen et al. (6) reported that 3.5% desired a reversal operation and that 0.8% either had obtained reversal or were waiting to obtain it. In an earlier Danish study on 547 women who were interviewed after a median time period of 50 mo after sterilization, 1% requested reversal surgery (12). In the numerous cross-sectional reports and retrospective studies on the subject of request for reversal information (12, 14, 15, 17, 19, 20, 22 25) young age at sterilization has been the one variable consistently associated with such requests, a finding confirmed by our results. In one such study, for example, Divers (24) reported that women who later requested reversal were, on average, 9 y younger at sterilization than were women who did not request reversal. The earlier the sterilization is carried out, the longer the remaining period of fertile life and the greater the chances of changes in marital status or of loss of a child, all of which may lead to a change in the desired family size (13). A change in the desired family size is the most commonly cited reason for poststerilization regret among women in this cohort (5). Although some studies identify the number of living children as a risk factor for requesting reversal information (15, 19 21), many others fail to detect a significant effect on the occurrence of request for reversal information when age at sterilization is controlled for (4, 11, 13, 16 18, 23, 24). In the present study, we confined the analysis regarding number of living children to women with interval 896 Schmidt et al. Poststerilization reversal information requests Vol. 74, No. 5, November 2000

6 sterilization and found no relationship between the number of living children and requests for reversal information. The completed CREST data set facilitated the evaluation of 3 measurable outcomes of poststerilization regret: selfreported regret (5), requests for information regarding sterilization reversal, and actual reversals. Young age at sterilization was the strongest predictor for all 3 outcomes. In our analysis, we found that the cumulative probability of requesting reversal information did not differ materially between women sterilized postpartum after a vaginal delivery and those sterilized during the early interval period. Several previous reports failed to identify an association between timing of sterilization and poststerilization regret (14, 24, 25). However, none of these analyses considered whether regret differed among women who had interval sterilizations within a short time after birth and those whose sterilizations occurred many years after the birth of their youngest child. Small sample size precluded our drawing conclusions about the role of timing of tubal sterilization for women who actually obtained reversal. The present analysis is subject to several limitations. First, in a study of such long duration, loss to follow-up is unavoidable. Women preferentially lost to follow-up were more likely to be aged 30 y, nonwhite, and married (data not shown). Although the loss of women who were young and nonwhite may have caused us to underestimate the true measure of effect, the loss of married women is likely to have had the opposite effect. Second, we were unable to assess the effect of additional characteristics present at sterilization that may influence the likelihood of seeking reversal information, such as level of contentment with presterilization counseling, knowledge of and attitudes toward alternative methods of contraception, and marital disharmony. Among a subsample of women (n 3,669) we did have limited information on the person who had the greatest influence on the decision to undergo sterilization. The proportion of women who stated that their partners, rather than they themselves, exercised the greatest influence on the decision for sterilization was not significantly different among young women (15 24 y) who requested reversal information (6.7%) than among older women (5.4%) who requested this information. Thus, it appears unlikely that the high probability of requesting reversal information among young women was biased by characteristics of their decision making. Last, it is unclear whether our findings are generalizable to the entire United States. Although the cohort was diverse and from centers throughout the country, it was selected primarily to test hypotheses regarding the safety and effectiveness of sterilization methods and not to represent the population of women sterilized in the United States. As has been noted previously (2, 26), the measurement of poststerilization regret presents many challenges. For example, there is uncertainty about the intensity of poststerilization regret reflected by the outcome we used, requesting information about sterilization reversal. The somewhat nonspecific nature of the questionnaire item (which includes not only medical personnel but also other people to whom the request for reversal information has been directed) may have added to that uncertainty. However, we attempted to evaluate the validity of this measure by asking a subset of women who requested information about reversal whether they had actually requested a reversal procedure. For this subset, the majority of the women who requested information also actually requested to have the procedure. However, only a small proportion of either group actually had a reversal procedure. Because health insurance plans in the United States usually do not cover sterilization reversals, financial resources likely represent an important factor in the decision-making process. A subsample of women who had requested reversal information (110/698) was asked why they did not have the reversal procedure. The most frequently stated reason (50%) for not obtaining the reversal procedure was that they could not afford such an operation. The second most frequently stated reason for this decision (34%) was other. For the other category, a variety of medical and private reasons were identified without any one such reason predominating. Our study suggests that young women are at increased risk for poststerilization regret, regardless of their number of living children or whether their sterilizations are performed on an interval or postpartum basis. Regret after sterilization is difficult to define and measure, and it is impossible from our study to determine the impact that the measures of regret we assessed have on women s lives. However, the observation that such a high proportion of women asked for information about sterilization reversal is striking. It is also not possible to estimate the extent to which young women who are dissuaded from sterilization might regret that decision; probabilities of contraceptive failure for alternative methods range from 2.3% (for hormone implants) to 19.8% (for periodic abstinence) during the first year of typical use (27). Surely, our data and the findings of others regarding the importance of young age should not be impetus to return to the restrictive formulas often used in the 1960s and 1970s to determine candidacy for sterilization. On the other hand, the impact of young age at sterilization on the likelihood of later regret is so compelling that it warrants extra emphasis in presterilization counseling. Young women should be informed not only that tubal sterilization is intended to be permanent but also that highly effective long-term (intrauterine devices, injectable and implantable steroid hormones) and short-term (oral contraceptive pills) methods are available. Although we believe that young women should not be denied sterilization because of their age, young women who choose to use temporary, highly effective methods may be well served by that choice. Most young women who choose sterilization will not regret having been sterilized, but a FERTILITY & STERILITY 897

7 substantial proportion will. In a society in which 50% of marriages end in divorce, it is difficult to predict which young women will be in that large minority of women who wish they had made another choice. References 1. Abma J, Chandra A, Mosher W, Peterson L, Piccinino L. Fertility, family planning, and women s health: new data from the 1995 National Survey of Family Growth. National Center for Health Statistics. Vital Health Stat 1997;23(19): Miller WB, Shain RN, Pasta DJ. The nature and dynamics of poststerilization regret in married women. J Appl Soc Psychol 1990;20: Grubb GS, Peterson HB, Layde PM, Rubin GL. Regret after decision to have a tubal sterilization. Fertil Steril 1985;44: Wilcox LS, Chu SY, Peterson HB. Characteristics of women who considered or obtained tubal reanastomosis: results from a prospective study of tubal sterilization. Obstet Gynecol 1990;75: Hillis SD, Marchbanks PA, Tylor LR, Peterson HB, for the U.S. Collaborative Review of Sterilization Working Group. Poststerilization regret: findings from the U.S. Collaborative Review of Sterilization. Obstet Gynecol 1999;93: Platz-Christensen JJ, Tronstad SE, Johansson O, Carlsson SA. Evaluation of regret after tubal sterilization. Int J Gynecol Obstet 1992;38: Wilcox LS, Zeger SL, Chu SY, Baker ED, Zeger SL, Peterson HB. Risk factors for regret after tubal sterilization: 5 years of follow-up in a prospective study. Fertil Steril 1991;55: Peterson HB, Xia Z, Hughes JM, Wilcox LS, Tylor LR, Trussel J, for the U.S. Collaborative Review of Sterilization Working Group. The risk of pregnancy after tubal sterilization: findings from the U.S. Collaborative Review of Sterilization. Am J Obstet Gynecol 1996;174: Hillis SD, Marchbanks PA, Tylor LR, Peterson HB, for the U.S. Collaborative Review of Sterilization Working Group. Tubal sterilization and long-term risk of hysterectomy: findings from the U.S. Collaborative Review of Sterilization. Obstet Gynecol 1997;89: Kleinbaum DG. Survival analysis: a self-learning text. New York: Springer-Verlag, Marcil-Gratton N. Sterilization regret among women in metropolitan Montreal. Fam Plann Perspect 1988;20: Thranov I, Kjersgaard AG, Rasmussen OV, Hertz J. Regret among 547 Danish sterilized women. Scand J Soc Med 1988;16: Bordahl PE. Tubal sterilization. A prospective long-term investigation of 218 sterilized women. Acta Obstet Gynecol Scand 1984;128(Suppl): Marcil-Gratton N, Duchesne C, St. Germain-Roy, Tulandi T. Profile of women who request reversal of tubal sterilization: comparison with a randomly selected control group. CMAJ 1988;138: Hardy E, Bahamondes L, Osis MJ, Costa RG, Faundes A. Risk factors for tubal sterilization regret, detectable before surgery. Contraception 1996;54: Taylor PJ, Freedman B, Wonnacott T, Brown S. Female sterilization: can the woman who will seek reversal be identified prospectively? Clin Reprod Fertil 1986;4: Vemer HM, Colla P, Schoot DC, Willemsen WNP, Bierkens PB, Rolland R. Women regretting their sterilization. Fertil Steril 1986;46: Allyn DP, Leton DA, Westcott NA, Hale RW. Pre-sterilization counseling and women s regret about having been sterilized. J Reprod Med 1986;31: Warren CA, Monteith RS, Johnson JT, Oberle MW. Tubal sterilization: questioning the decision. Popul Stud 1988;42: Murray J. A review of women requesting reversal of tubal sterilization. Aust N Z J Obstet Gynecol 1980;20: Leader A, Galan N, George R, Taylor PJ. A comparison of definable traits in women requesting reversal of sterilization and women satisfied with sterilization. Am J Obstet Gynecol 1983;145: Abraham S, Jansen R, Fraser IS, Kwok CH. The characteristics, perceptions, and personalities of women seeking a reversal of their tubal sterilization. Med J Aust 1986;145: Ramsay IN, Russell SA. Who requests reversal of female sterilization? A retrospective study from a Scottish unit. Scott Med J 1991;36: Divers WA. Characteristics of women requesting reversal of sterilization. Fertil Steril 1984;41: Boring CC, Rochat RW, Becerra J. Sterilization regret among Puerto Rican women. Fertil Steril 1988;49: Chandra A. Surgical sterilization in the United States: prevalence and characteristics, National Center for Health Statistics. Vital Health Stat 1998;23(20): Trussell J, Vaughan B. Contraceptive failure, method related discontinuation and resumption of use: results from the 1995 National Survey of Family Growth. Fam Plann Perspect 1999;31:64 72, Schmidt et al. Poststerilization reversal information requests Vol. 74, No. 5, November 2000