Contraception with NORPLANT implants and NORPLANT-2 implants (two covered rods). Results from a comparative clinical study in Sweden.
Two-hundred-and-forty healthy women, ages 18 to 40 years, were randomized in a ratio of 2:5 to use NORPLANT implants or NORPLANT-2 implants. Through three years of use, no pregnancies were recorded among women using NORPLANT implants and two pregnancies were noted among women using NORPLANT-2 implants resulting in a cumulative net pregnancy rate of 1.3 +/- 0.9 per 100 acceptors (mean +/- SE) by the end of year three. This difference was not statistically significant. During the fourth year, no pregnancies were observed in the NORPLANT group, but 4 pregnancies occurred in the NORPLANT-2 group. The most common reason for terminating the study was bleeding disturbances. During the first year there were significantly more terminations due to bleeding problems in the NORPLANT group than in the NORPLANT-2 group. However, during the second year of use the proportion of women discontinuing for bleeding problems dropped considerably among NORPLANT users and during the third year very few women in either group discontinued because of bleeding problems. The continuation rates after one year were for NORPLANT users 59.4% and for NORPLANT-2 users 77.2%. Corresponding figures after three years of use were 46.1% and 51.7%, respectively. The second most common reason for discontinuation was depression and other mood changes. In both groups we noted a slight increase in weight during the study and a slight decrease in blood pressure and hemoglobin levels with time. In conclusion, both NORPLANT and NORPLANT-2 implants are very effective methods for contraception. The efficacy of NORPLANT-2 implants, however, was not acceptable during the fourth year of use in this study. The latter system could, however, become a suitable three-year contraceptive method, possibly with less bleeding disturbances than NORPLANT in the first year.
D000293:Adolescent; D000328:Adult; D002986:Clinical Trials as Topic; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D016912:Levonorgestrel; D008597:Menstrual Cycle / Q000187:drug effects; D009644:Norgestrel / Q000008:administration & dosage*; D011247:Pregnancy; D013548:Sweden
D003271:Contraceptive Agents, Female; D003692:Delayed-Action Preparations; D009644:Norgestrel; D016912:Levonorgestrel