Abstract

PIP: A double-blind randomized clinical study to compare the use-effectiveness and bleeding patterns among women using the triphasic preparations levonorgestrel (LNG) 50-125 mcg/ethinyl estradiol (EE) 30-40 mcg; microgynon 30 (LNG 150 mcg/EE 35 mcg), and pill No. 1 NNET 600 mcg/EE 35 mcg) during February and July 1983. The recruited volunteers totalled 279 women, 96 in the 1st group, 93 in the 2nd, and 90 in the last. Using life table calculations, the cumulative continuation rates/100 women at the end of 24 weeks were 82.3, 81.6, and 80.9. There were no statistical differences between them. The incidence of side effects was also similar. As to the bleeding patterns, the triphasic preparation had less impact on the menstrual cycle; there was less spotting and less effect on the length of the menstrual flow. Results showed that the triphasic preparation which contained much smaller doses of progestogen is an effective low-dose contraceptive. (author's modified)