Tubal Occlusion Failures: Implications of the CREST Study on Reducing the Risk

, , AVSC International, New York City.


Medscape General Medicine. 1997;1(2) 

In This Article

Abstract and Introduction


Through data reported in the US Collaborative Review of Sterilization (CREST) study, we have learned that 10-year cumulative failure rates of sterilization done by tubal occlusion are much higher than originally thought. While the small, earlier studies reported failure rates as low as 3 to 4 per 1000 procedures, they often followed women for only 2 years after the procedure. When pregnancies occurred during this period, the operative assumption was that these failures were due to incomplete occlusion. Most reports have not addressed the possibility of recanalization leading to failures. The CREST findings, however, suggest that failure rates are closer to 18 per 1000, depending on the occlusion method used and characteristics of the patient. This study also shed light on the factors that increase the risk of ectopic pregnancy after sterilization procedures. These new long-term data indicate that all providers should know that pregnancy, including ectopic pregnancy, can occur in women with history of tubal occlusion for sterilization, especially many years after the original procedure.


Sterilization is now the most commonly used method of family planning in the world. In 1990, about 191 million married women of reproductive age relied on sterilization (of themselves or their partners) for permanent contraception. This number represents 22% of married women of reproductive age in developing countries and 11% in developed countries.[1] In the US, sterilization has become the most commonly used method of contraception among married couples. Sterilization is an appealing option because it is generally safe, effective, and easily performed on both men and women. As a result of the US Collaborative Review of Sterilization (CREST) study,[2] long-term follow-up data of traditional occlusion methods for female sterilization are now available (Figs. 1A-1E). These findings show that all methods for occluding the fallopian tubes are highly effective in the short term; however, the long-term cumulative failure rate and ectopic pregnancy rate are higher than expected. As a result of this new information, more attention must be given to rule out pregnancy, including ectopic pregnancy, when evaluating the poststerilization patient with missed periods, pain, or irregular bleeding. In addition, these findings have implications for evaluating, counseling, and selecting patients prior to sterilization, as well as in choosing which sterilization method is best for each patient.

Figure 1A. Ligation with Partial Salpingectomy: Fallopian tubes are tied with suture material and cut. The modified Pomeroy method, which is common, involves tying a small loop of tube and then cutting off the top segment the of loop. In the United States, ligation with partial salpingectomy is most often used when sterilization procedures are performed postpartum. Procedure is performed through an abdominal incision.
Figure 1B. Unipolar Coagulation: Electrical current is used to block fallopian tubes. Because of extensive damage to tubes, unipolar coagulation is hard to reverse. This method can be performed through the laparoscope.
Bipolar Coagulation: Electrical current is used to block the fallopian tubes. This method usually causes less damage to tubes than unipolar coagulation, but this characteristic may lead to the method's lower rate of effectiveness. Bipolar coagulation can be performed through the laparoscope.
Figure 1C. Silicone Bands: Small, round elastic band is stretched and then slipped over a loop of fallopian tube. Using a special applicator, the surgeon applies bands through a laparoscope or an abdominal incision. Since damage to tubes is minimal, likelihood of reversal following this method is higher than with other occlusion techniques.
Figures 1D. Spring Clips: Clip is attached across each fallopian tube. In the US, the Hulka clip has been most widely used.
Figure 1E. The FDA has recently approved the Filschie clip, which has been widely and effectively used in Europe. Using a special applicator, the surgeon applies clips through a laparoscope or abdominal incision. Likelihood of reversal following this method is good, since clip does least amount of damage to tubes.