Female sterilization using chemical agents.

Conventional surgical approaches for female sterilization cannot be used in many areas of the developing world because of lack of specially trained physicians. A safe, effective, inexpensive, and simple procedure is needed that can be performed without surgical entry of the woman's abdominal cavity. Transcervical introduction into the fallopian tubes of a pharmacologically active agent to produce tubal closure appears to be a promising approach. A problem with this approach is the toxic effects of agents not only on the tubal epithelium but also on the peritoneum and pelvic viscera as well. Chemical agents that have been tested for tubal closure include: caustic, sclerosing, granuloma-producing, cytotoxic, acids and bases, tissue adhesives, and agents that are not pharmacologically active (e.g., silicone rubber and hot water). The search is on to find a system whereby a toxic chemical can be delivered to the site where it is to produce the desired destruction without damaging surrounding tissues. Most of the above agents produce unwarranted toxic effects. Quinacrine and methylcyanoacrylate (MCA) are possible exceptions. They do not appear to be toxic in the peritoneal cavity unless introduced in very large amounts. Substances of low viscosity facilitate delivery, but they are difficult to work with and to deliver using a catheter, a cannula, or other delivery techniques. Successful delivery occurs in those systems in which the tubal orifice is cannulated directly or blindly, or those in which the uterus and fallopian tubes become a closed system and medication is forced into the tubes under pressure. MCA has been delivered using 2 systems which produce a close system by blocking off the uterine outflow tract with an inflatable balloon. Various systems for quinacrine have also been developed and trials are underway to determine its effectiveness. The delivery systems for both MCA and quinacrine appear to be relatively simple and easy to use, but there is a need to increase the efficacy in order to achieve the greatest utility without resorting to multiple application, and to follow up a substantially large number of women to determine the long-term sequelae of the systems. Clinical trials on silver-based compounds, ethanol-formaldehyde, quinacrine, and MCA are described.