3-YEAR CLINICAL-TRIAL WITH LEVONORGESTREL SILASTIC IMPLANTS

Silastic implants containing the progestin, levo-norgestrel, were tested as long-term contraceptives in 101 women. After 3 yr exposure and 2998 woman-mo. of use, no pregnancies occurred. The continuation rates were 87% at 12 mo., 79% at 24 mo. and 66% at 36 mo. The most important side effect was excessive or irregular bleeding during the 1st yr. No treatment was offered for this side effect other than vitamins and Fe or change of method, with the exception of 3 cases where ethinyl estradiol was used 1 time for 2 wk each. Bleeding disturbances led 8 patients to ask for removal of implants. Other side effects were headache, acne and lower abdominal pain. Blood and urine analysis tested 17 different parameters and all but plasma cortisol remained within normal limits throughout the study. A general tendency toward lowered cortisol values was observed and 2 subjects had more than 1 value below the normal limit for the population during the study. Glucose tolerance tests during the 2nd yr were abnormal in 2 women with familial diabetes but they returned to normal values spontaneously at the next test. Levo-norgestrel implants offer effective protection against pregnancy during the 1st 3 yr of continuous use. Their acceptability and few side effects justify larger trials, especially if treatment of bleeding irregularities is introduced.