Sterilization option now under research

Sterilization continues to be a leading contraceptive choice for women in the United States; between 2006 and 2008, 10.3 million women looked to the method for birth control.1 Worldwide, 220 million couples use tubal sterilization or vasectomy as their chosen contraception method.2

"Globally, surgical sterilization is the most common and effective method of birth control," notes Jeffrey Jensen, MD, MPH, Leon Speroff Professor & Vice Chair of Research in the Department of Obstetrics & Gynecology at the Oregon Health & Science University in Portland. "Unfortunately, the acceptability of this important method is limited by its high cost, scarcity of providers, and surgical risks, particularly in lesser-developed nations."

Researchers are looking at the development of novel, non-surgical methods of sterilization to improve access to the fertility control option, and thus reduce the number of unintended pregnancies, says Jensen. Jensen's research team is eyeing the use of polidocanol foam, currently used in varicose vein therapy, as a potential low-cost, nonsurgical long-term contraceptive method.3

The team recently has received Phase II funding for its project through the Grand Challenges Explorations, an initiative created by the Bill & Melinda Gates Foundation in Seattle. The initiative allows scientists to test ideas to address persistent health and development challenges. The Portland research team received similar Phase I testing funds in 2010 to examine the potential sterilization option.

Several chemical agents have been evaluated for possible use in sterilization, but only quinacrine has been tested in humans. However, the use of quinacrine for nonsurgical sterilization has been halted in several countries due to safety, efficacy, and ethical concerns.4

Could approach work?

Polidocanol works by causing excess connective tissue to form within the cell lining of blood vessels, thereby collapsing and closing the vessels. It was first used in the 1960s in Germany as a sclerosing agent for the cosmetic treatment of veins, and it quickly was adopted for that use in many European countries. It is approved by the Food and Drug Administration for treatment of varicose and spider veins. The drug has been intensely studied, and it has a high therapeutic index of safety.5

Since polidocanol is a registered drug for sclerosis of veins, the regulatory pathway for approval of this drug for use as a nonsurgical method of female sterilization would be much faster than for a new chemical entity that has not yet been cleared by regulatory authorities, says Jensen.

Polidocanol foam administered through the cervix via a small balloon catheter by a non-physician health care worker could "revolutionize" access to permanent contraception, says Jensen. "We could move sterilization from a risky surgical technique to a safe, well-tolerated procedure easily accessed in any village," states Jensen. "Healthcare workers could literally transport all the needed equipment to provide this service to a rural community in a small backpack."

Consider this explanation

How could such an approach work? Jensen provides the following scenario: on approximately day 5 of the menstrual cycle, a balloon catheter is inserted transcervically into the uterine cavity, and the balloon is inflated above the internal os. The polidocanol foam is introduced through the catheter into the uterine cavity, and it then flows out the fallopian tubes. This technique does not require visualization or canalization of the tubal ostia, explains Jensen. This treatment results in scaring confined to the intramural portion of the tube, states Jensen.

Experiments are underway in nonhuman primate models to optimize the approach such that a single treatment results in bilateral occlusion without adverse nontarget effects, says Jensen. Once an optimal strategy is developed, a contraceptive study will be initiated in nonhuman primates, and early phase clinical trials in women will begin. Concurrent with these efforts will be additional research to determine acceptability and product design characteristics to facilitate introduction of the technology in low-resource settings, he states.

While the research is still in early phases, it is important that science continue to explore such contraceptive options, says Mitchell Creinin, MD, professor and chair of the Department of Obstetrics and Gynecology at the University of California, Davis School of Medicine.

"I think the biggest thing is that we continue to strive for things to give women the options that they want, that potentially build on what we already have," observes Creinin. "There are companies who make 'me too' products, [but] is there a way we can provide women with highly-effective methods in a way that is cheaper, easier to access, and that is not only good for people with lots of money, but for those in developing countries, or people in our own country who are poor?"

References

  1. Mosher WD, Jones J. Use of contraception in the United States: 1982-2008. Vital Health Stat 2010; 23(29):1-44.
  2. EngenderHealth. Contraceptive Sterilization: Global Issues and Trends. New York; 2002.
  3. Jensen JT, Rodriguez MI, Liechtenstein-Zábrák J, et al. Transcervical polidocanol as a nonsurgical method of female sterilization: a pilot study. Contraception 2004; 70(2):111-115.
  4. Schwartz J, Gabelnick HL. Contraceptive research and development. In: Hatcher RA, Trussell J, Nelson AL, et al. Contraceptive Technology: 20th revised edition. New York: Ardent Media; 2011.
  5. Jensen JT. Nonsurgical sterilization for women. Presented at the Future of Contraception Initiative meeting. Seattle; October 2011