Please note: This archive was last updated in 2005.

RHO archives : Topics : Contraceptive Methods

Contraceptive Research and Development 

Overview

Although more than 100 contraceptive technologies currently are under development, most are modifications of existing products or alternative delivery systems for existing steroids. A systematic review of the environment surrounding contraceptive research and development has documented the many challenges and obstacles to bringing new products to market (National Academy of Sciences/Institute of Medicine 1994; WHO 1994). International efforts supported by the Rockefeller Foundation and other donors are working to revitalize the field of contraceptive research and development. Much research is focused on improved barrier methods for women for both pregnancy and STI prevention, menses inducers, and methods for men (PATH/Outlook 1995). Researchers (including those at CONRAD and the Population Council) also are working to develop new spermicides and microbicides.

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New female barrier methods

Research has continued to develop several new female barrier methods that are modified versions of diaphragms, cervical caps, and sponges. These devices have been designed to be easier to insert and remove, and more difficult to dislodge during intercourse.

The Lea's Contraceptive™ is a modified diaphragm-like device in one size. It is available as an over-the-counter product in Germany, and was approved by the United States Food and Drug Administration (U.S. FDA) in March 2002. It should remain in place at least 8 hours after intercourse, but be worn no longer than 48 hours before removing to wash. A study carried out by CONRAD indicated that the 12-month pregnancy rate of the Lea Contraceptive™  compared favorably with other barrier methods. Pregnancy rates associated with the Lea Contraceptive were 15 percent, compared to the 10 to 21 percent for the standard diaphragm with spermicide (FHI 2000; CONRAD 2000).

The FemCap™ is a modified cervical cap with a strap to aid in removal of the device. It is available in some European countries and was approved for use in the United States in March 2003. In a study by CONRAD and Family Health International, the FemCap™ used with spermicide was found to be somewhat less effective as a contraceptive than a conventional diaphragm with spermicide. CONRAD estimates a 12-month pregnancy rate (based on 6-month pregnancy rates) of about 23 percent for the FemCap™ (FHI 2000; CONRAD 2000).

Two contraceptive sponges currently are available, primarily in Canada and Europe. The Pharmatex sponge—available in Europe—contains the spermicide benzalkonium chloride. The Protectaid™ Sponge contains a combination of spermicides. See the Contraceptive Sponge: New Choices discussion in RHO's Female Barrier Methods section for details about these devices.

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New implants

Norplant, introduced in the 1980s, was the first contraceptive implant that became available to family planning programs. Despite the changes in menstrual bleeding patterns common to all progestin-only methods, Norplant proved highly acceptable to many women. Progestin implants for female contraception are now growing into a family of options. So far, four different progestins and two polymers have been used to design six different implants (IPPF 2000):

Norplant
(Population Council)

  • A system of six Silastic capsules that release levonorgestrel
  • Duration of action: 5 years
  • Registered in 60 countries
  • Used by nearly 6 million women

Jadelle
(Population Council)

  • A system of two Silastic rods that release levonorgestrel
  • Duration of action: 5 years
  • Ongoing registration in Europe

Implanon
(NV Organon)

  • A single implant system that releases etonogestrel
  • Duration of action: 3 years
  • Registered in Australia, Indonesia, and 11 European countries
  • Introduced in the Netherlands and the United Kingdom in September 1999
Uniplant
  • A single-rod, one-year implant that delivers nomegestrol acetate
  • No commercialization plans at this time

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New injectables

Two new, once-a-month, combined injectable contraceptives have been developed by the Special Programme of Research in Human Reproduction (HRP) of the World Health Organization. Both Cyclofem (also called CycloProvera or Lunelle) and Mesigyna have been tested in large multicenter clinical trials, and have been proven effective with relatively low incidence of side effects. Recent studies on the efficacy, causes of discontinuation, and side effects of the these two injectable contraceptives in Egypt found they could be a positive addition to contraceptive choice (Hassan 1999).

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Microbicides

With almost 34 million people worldwide living with HIV/AIDS—95 percent of whom are in developing countries—the need for additional prevention options has become urgent. Globally, women represent 43 percent of people infected by HIV/AIDS; more than 55 percent of people infected in sub-Saharan Africa, 30 percent in Asia, and 20 percent in Europe and the United States (Population Council and International Family Health 2000).

A microbicide—a compound that can be applied inside the vagina or rectum to protect against sexually transmitted infections—ultimately may be formulated as a gel, cream, film, or suppository. An ideal microbicide should be effective, safe, acceptable, affordable, colorless, odorless, stable, easy to store and use, available in a variety of preparations, available in contraceptive and noncontraceptive formulations, and available without a prescription. At this time, however, the top priorities are to develop a microbicide that would provide protection when used consistently, and to develop a microbicide that would be used by those who need it most (FHI 2000).

It is important to support the development of microbicides because: (1) diagnosis and treatment of STIs continues to spread despite knowledge of successful HIV-prevention strategies; (2) microbicides offer an alternative to condoms as a feasible means of primary prevention; and (3) currently available HIV-prevention techniques may not be feasible for many women in resource-poor settings. In addition, microbicides are an option that women can use that may not require the cooperation of her partner. A recent cost-benefit analysis, conducted at the London School of Hygiene and Tropical Medicine, indicated that introducing a microbicide which reduces infection by 40 percent at 30 percent coverage could avert approximately six million HIV infections among men, women, and children in 73 lower-income countries (WHO 2003).

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Microbicide research

Microbicide research falls into two general approaches: (1) developing and testing new substances, and (2) investigating the potential microbicidal activity of existing spermicidal products and different formulations of these products.

Although researchers are examining more than 50 substances as possible vaginal microbicides—and about a quarter of these are in various stages of testing with humans—this group of experimental products is years away from being widely available.

The Alliance for Microbicide Development maintains a database that lists microbicide products by stage of development (http://209.190.247.198/microbicide/pdfs/Clinical.Trials.Info.Center.Planned.Ongoing.09Sep03.pdf). The database was last updated in September 2003.

Products being evaluated act in one or more of the following mechanisms.

Mechanism

Mode of Action

Examples

Inactivates or kills infectious agents.

Detergent-like chemicals that disrupt the lipid membrane of the cell and the surface of HIV.

Existing spermicides such as nonoxynol-9, octoxynol-9,  benzalkonium chloride, menfegol, and N-docasanol. (Also see the spermicides page.)

Blocks attachment to target cells and inhibits entry of infectious pathogens.

Prevents infection by blocking attachment of pathogens to mucosal surface of target cells.

Sulphated and sulponated polymers such as PC-515 (carrageenan), Pro-2000, and Dextrin 2 Sulphate.

Prevents infection with/replication of infectious agents.

Antiretroviral agents prevent HIV from replicating in the cells.

Anti-HIV antibodies combat pathogens before infection occurs.

Antiretroviral agents include PMPA gel.

Plantibodies (anti-HIV antibodies genetically engineered from plants).

Enhances vaginal defense.

Enhances naturally acidity of the vagina.

Supplements production of hydrogen peroxide.

Both mechanisms are hostile to pathogens, including HIV.

Buffer Gel and Acidform help maintain natural levels of acidity in the presence of semen.

Suppositories containing lactobacillus—which live normally in the healthy vagina—produce hydrogen peroxide.

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Quinacrine sterilization

Intrauterine application of quinacrine hydrocholoride is a method of nonsurgical female sterilization that has received considerable attention during the last decade and has generated significant controversy. To date, more than 100,000 women in over 20 countries have been sterilized using this method, mainly in Viet Nam, India, and Pakistan. Inserted directly into the uterus in pellet form, quinacrine liquefies and flows into the fallopian tubes, causing permanent scarring. Although recorded failure rates and persistent side effects related to quinacrine sterilization have been low, controversy has developed around quinacrine's long-term safety, efficacy, and link to upper genital tract infections. As a result, several countries and regulatory agencies, including the U.S. FDA, have taken steps to ban both the manufacture and use of quinacrine for sterilization (PATH/Outlook 1999). Animal trials are currently underway to resolve the toxicological questions about quinacrine's safety.

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