Norplant appears to have patterns of adverse effects that are very similar to those of combined oral contraceptives, with the exception of bleeding disturbances.
In settings where postmarketing surveillance studies were carried out, Norplant proved to be a safe, well-tolerated, and highly effective contraceptive method.
Center for Biomedical Research Population Council
Between 1990 and 1996, the Population Council conducted a series of studies to assess the health of women during use of either Norplant or what has been popularly referred to as "Norplant 2," now referred to as the LNG ROD or, outside the United States, Jadelle. The latter is an implant consisting of two rods that slowly release their levonorgestrel contents over an approved duration of efficacy of 3 years. The studies of this new formulation were undertaken to provide sufficient information to permit its registration, as well as to obtain additional information for revision of the efficacy labeling on Norplant. In the discussion that follows, "Norplant" refers to the slightly modified soft-tubing version approved by the Food and Drug Administration (FDA) for use in the United States.
The studies involved a total population of 2,798 women in seven countries,* 43 percent of whom were from the United States.
The first randomized study followed 199 women using an old version of the LNG ROD and 199 women using a new version of the LNG ROD. This study measured blood levels of drug, efficacy, and safety.
The second randomized study involved 600 women using Norplant with the "soft" tubing and 600 women with the LNG ROD. It was mainly conducted outside the United States.