PROJECT
Subdermal Implants for Women

In November 2002, the Population Council received approval from the US Food and Drug Administration (FDA) for the use of Jadelle^®, a two-rod contraceptive implant system releasing the progestin levonorgestrel, for five years continuously. The FDA had previously approved Jadelle as effective for three years.

In an effort to secure approval of Norplant^® (the six-implant levonorgestrel system) for seven years, work has focused on determining the residual amount of drug remaining in the implants in relation to their duration of use and other factors in an attempt to ascertain why some women became pregnant while others did not.

Many of the new contraceptive methods under development employ Nestorone^®, a versatile synthetic progestin similar to the natural hormone progesterone. Although Nestorone is not active when administered orally, it can be used in rings, patches, gels, and implants, either combined with an estrogen or alone, for contraception, hormone treatment, or hormone replacement therapy. It is particularly appropriate for use by breastfeeding mothers.

Building on experience gained from the development of Norplant and Jadelle, the Council conducted studies on a single-rod implant containing Nestorone for lactating women meant to protect against pregnancy for two years by completely inhibiting ovulation. Several clinical studies of the Nestorone implant have demonstrated its effectiveness as a contraceptive. Nestorone is also an effective treatment for endometriosis. A study in Latin America tested the effectiveness of a redesigned single implant to be used for two years. A benefit of a Nestorone implant is that the steroid does not affect serum lipoprotein patterns, carbohydrate metabolism, or liver proteins.

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Population Council researchers

Frederick Schmidt, Irving Sivin

Donors

The Lita Annenberg Hazen Foundation

The George J. Hecht Fund

The William and Flora Hewlett Foundation

US Agency for International Development

* Not available from the Population Council.

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