(SACRAMENTO, Calif.) -- The risk of pregnancy among women using a newer method of planned sterilization called hysteroscopic sterilization is more than 10 times greater over a 10-year period than using the more commonly performed laparoscopic sterilization, a study by researchers at Yale University and UC Davis has found.
Published online today in the medical journal Contraception, the study found the higher risk of pregnancy with a newer sterilization method marketed under the brand name Essure®.
"This study provides essential information for women and their doctors discussing permanent sterilization," said lead study author Aileen Gariepy, assistant professor in the Department of Obstetrics, Gynecology and Reproductive Sciences at the Yale School of Medicine.
Female surgical sterilization is the most popular method of pregnancy prevention worldwide and the most commonly used method of contraception among women age 35 and older in the United States. Each year, 345,000 U.S. women undergo sterilization procedures, and a total of 10.3 million U.S. women rely on female sterilization for pregnancy prevention.
Hysteroscopic sterilization is a multi-step process that requires women to have a procedure to place coils inside the opening of the Fallopian tubes, use another method of contraception for three months after the procedure, and then have a special X-ray test in which dye is pushed into the uterus to confirm whether the tubes are blocked.
"When Essure was first approved by the Food and Drug Administration in 2002, data presented to physicians and patients only included those women who successfully completed all of the steps to be sterilized using the procedure," said study co-author Mitchell Creinin, professor and chair of the Department of Obstetrics and Gynecology at the UC Davis School of Medicine.
"However, physicians quickly realized that at least 1 in 10 women would not be able to have the coils placed and that many would not return for follow-up testing," he said.
The study uses data in the published literature to model what happens to women who start down a path of wanting a laparoscopic sterilization or hysteroscopic sterilization, including those who do not successfully have the procedure. The computer model, called a decision analysis, calculates what could occur in a theoretical group of 100,000 women taking into account all of the potential options that could happen in each step of the process.
The authors found that pregnancy risk after hysteroscopic sterilization is primarily accrued in the first year after initiating the process because hysteroscopic sterilization is not immediately effective. Conversely, laparoscopic sterilization is immediately effective.
The major findings by Gariepy and colleagues include that pregnancy rates in the first year for women planning hysteroscopic sterilization are 57 per 1,000 women, compared with about 3 to 7 per 1,000 women for laparoscopic sterilization. The total pregnancy rate over 10 years reached 96 per 1,000 women for hysteroscopic sterilization compared to only 24 to 30 per 1,000 women with a laparoscopic procedure. The authors accounted for other methods of contraception that would be used for women who did not have a sterilization procedure, including that some women who have a failed hysteroscopic procedure would choose a laparoscopic procedure.
Since its introduction, hysteroscopic sterilization has been performed on more than 650,000 women worldwide. This newer procedure can be performed in a doctor's office and does not involve abdominal incision or general anesthesia.
Many doctors and patients think that these factors make the procedure seem easier.
"However, for women who want to be sure they don't get pregnant, the current method of hysteroscopic sterilization still is not ready to be used for everyone," Creinin said.
There have been no studies comparing the effectiveness of hysteroscopic sterilization with laparoscopic sterilization.
"This limits providers' and patients' ability to make informed decisions," Gariepy said.
Gariepy also pointed out that unintended pregnancy resulting from sterilization failure can have serious consequences for both women's quality of life and maternal and neonatal health outcomes, and should be considered a significant adverse event.
"Women choose sterilization specifically to prevent any future pregnancies," Gariepy said. "If one sterilization method has a much higher risk of pregnancy, women and their doctors need to know that as they consider the overall risks and benefits of the procedure."
Other study authors include Xiao Xu of Yale and Kenneth Smith of the University of Pittsburgh.
The study was supported by a grant from the Society of Family Planning.
The UC Davis School of Medicine is among the nation's leading medical schools, recognized for its research and primary-care programs. The school offers fully accredited master's degree programs in public health and in informatics, and its combined M.D.-Ph.D. program is training the next generation of physician-scientists to conduct high-impact research and translate discoveries into better clinical care. Along with being a recognized leader in medical research, the school is committed to serving underserved communities and advancing rural health. For more information, visit UC Davis School of Medicine at http://medschool.