Seguimiento a largo plazo de mujeres tratadas con implantes anticonceptivos de levonorgestrel Norplant.

This report describe the long-term follow-up of 376 women who received Norplant implants in the period october 1974 through may 1979. One-hundred-and-ten subjects received replacement implants after variable lengths of use of the first set. The average levonorgestrel plasma levels declined steadily through eight years of use of Norplant capsules (r = -937). Values were 0.35 ng/ml, 0.29 ng/ml and 0.22 ng/ml at treatment years 1, 5 and 8, respectively. Levonorgestrel plasma levels after replacement with a second set of implants were similar to those observed after the first insertion, either when placed in the same site as the first set or in a different area. The levonorgestrel half-life after implant removal was 42 +/- 16 h (X +/- S.E.) and only trace amounts are detected after 96 h. Nineteen pregnancies occurred during 18,530 woman-months of use of the first set of implants, eleven of them during years 6 through 8 of treatment. The Pearl Index for the first years of Norplant implants use was 0.63. No pregnancy has occurred in 5.020 woman-months observed during treatment with a second set of capsules. Fifty-six women (14.9%) out of 376 acceptors of the first implant and 12 (10.9%) out of 110 acceptors of the replacement implants were terminated for other medical reasons, mainly side effects commonly associated with hormonal contraception. Removals for bleeding problems occurred in 5.6% and 3.6% of the acceptors of the first and second implant, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)