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a) The cumulative probability of becoming pregnant in 10 years is estimated to be 0.8% following partial removal of the tube for postpartum sterilization, and 2.0% following interval sterilization (based on U.S. data).
Female sterilization is the most effective long-term family planning (FP) method, other than vasectomy. Female sterilization is particularly effective when performed by partial removal of the tube, as with minilaparotomy, either:
- immediately postpartum, or
- at six or more weeks after delivery (interval sterilization).
In general, women sterilized at young ages have higher failure rates than women sterilized at older ages.
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a) Female sterilization is the only permanent female FP method. Annual pregnancy rates for minilaparotomy using partial salpingectomy, commonly the Pomeroy and Parkland techniques, are very low, but when failure occurs it is more often in the first or second years after surgery. Rarely do pregnancies occur after five years.
The best data come from a long-term US study. This study reports that the cumulative pregnancy rates during the first five years and for years six through ten are:
- for postpartum partial salpingectomy, 0.6 and 0.1 per 100 women, respectively;
- for laparoscopic silicone bands, 1.0 and 0.8 per 100 women; and
- for interval partial salpingectomy, the study does not have good, unbiased data. However, it may be reasonable to estimate the rates for interval partial salpingectomy as similar to the postpartum rates because studies in the past have demonstrated the interval procedure to be as or more effective than when performed postpartum.
Experts assume that the extremely low pregnancy rates in years six through ten will continue through years 11-20, which is very important for women wanting no more children. Because pregnancies are rare events following female sterilization, accurate pregnancy rates are difficult to determine from international data sources such as the Demographic and Health Surveys (DHS), and therefore are not routinely reported with pregnancy rates for other methods.
- Peterson HB, Xia Z, Hughes JM, Wilcox LS, Tylor LR, Trussell J. The risk of pregnancy after tubal sterilization: findings from the U.S. collaborative review of sterilization. American Journal of Obstetrics and Gynecology 1996;174:1161-70.
- Female sterilization: a guide to provision of services. Geneva: WHO, 1992.
- Moreno L, Goldman N. Contraceptive failure rates in developing countries: evidence from the demographic and health surveys. International Family Planning Perspectives 1991;17:44-9.
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b) The 10 year cumulative pregnancy rate is 1.8% for tubal sterilization by laparoscopy using silicone bands.
Silicone bands are the most common laparoscopic female sterilization method outside North America and Western Europe. Female sterilization by laparoscopy using silicone bands is equally effective as interval minilaparotomy techniques.
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b) Laparoscopic female sterilization by spring clip and bipolar electrocoagulation result in higher cumulative 10 year pregnancy rates, 3.7 and 2.5 per 100 women (whereas the 10 year pregnancy rate for a postpartum partial salpingectomy is 0.8 per 100 women). However, these laparoscopic occlusion techniques are used infrequently outside North America and Western Europe.
- Peterson HB, Xia Z, Hughes JM, Wilcox LS, Tylor LR, Trussell J. The risk of pregnancy after tubal sterilization: findings from the U.S. collaborative review of sterilization. American Journal of Obstetrics and Gynecology 1996;174:1161-70.
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c) The 10 year cumulative ectopic pregnancy rate is 0.73% for all methods of tubal sterilization combined.
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c) The 10 year cumulative ectopic pregnancy rates were higher in women who were younger than 30 at the time of the sterilization compared to women who were 30 or older at the time of the procedure, and in women who were sterilized by bipolar coagulation compared to women sterilized by any other method.
- Peterson HB, Xia Z, Hughes JM, Wilcox LS, Tylor LR, Trussell J. The risk of ectopic pregnancy after tubal sterilization. New England Journal of Medicine 1997;336:762-7.
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