Nilsson C G, Luukkainen T, Diaz J, Allonen H
Contraception. 1982 Apr;25(4):345-56. doi: 10.1016/0010-7824(82)90092-0.
The clinical performance of two levonorgestrel-releasing intrauterine devices (IUDs) with different release rates was studied and compared with a copper-releasing Nova-T device in a randomized partly double-blind multiclinical trial. Special attention was given to patterns of bleeding, hormonal side-effects, blood pressure and body weight. The clinical acceptability of the levonorgestrel IUDs was as good as that of the copper-releasing IUD. A highly significant decrease in the amount of menstrual blood loss was seen with the levonorgestrel-IUDs, the users of which experienced fewer days of bleeding than prior to insertion. Patients suffering from dysmenorrhea experienced relief from this symptom after insertion of a levonorgestrel-IUD. Some side-effects, usually referred to as hormonal, increased during the levonorgestrel-IUD use, but did not result in higher termination rates than with the Nova-T device. No changes in body weight were recorded for the levonorgestrel-IUDs and a slight decrease in both systolic and diastolic blood pressure was found after one year of use. No infections were recorded.