A multicenter comparative trial of triphasic and monophasic, low-dose combined oral contraceptives.

ABSTRACT

PIP: Researchers compared the efficacy, safety, and acceptability of a triphasic oral contraceptive (OC), Triquilar, with those of a monophasic OC, Lo-Femenal, among 1088 women attending clinics in Chile, the Dominican Republic, Ecuador, Sri Lanka, and the Sudan. Both OCs contained levonorgestrel and ethinyl estradiol. 90% of women in each group exhibited good user compliance. Only 1 unplanned pregnancy occurred in each group, and both pregnancies were attributed to user failure. The gross cumulative efficacy rates at 11 months were 0.3/100 woman-years for the triphasic OC and 0.2/100 woman-years for the monophasic OC. The continuation rate at 11 months was lower for Lo-Femenal than it was for Triquilar (80.8% vs. 84.6%), but the difference was not significant. The leading side-effect-related reason for discontinuation in both groups was headache. Another key reason for OC discontinuation in both groups was personal reasons, such as planning a pregnancy. Most women in both groups did not have menstrual complaints (78.8% for the Triquilar group and 77.1% for the Lo-Femenal group). Intermenstrual bleeding rates were low (7.6% for the Triquilar group and 9% for the Lo-Femenal group). Significant intercenter differences for women reporting intermenstrual bleeding and side effects (e.g., headaches) existed (p .05). Women from both groups at the clinic in the Sudan always had lower reports of intermenstrual bleeding than those at the other clinics. In fact, no woman discontinued OC use because of intermenstrual bleeding in the Sudan. Women in Sri Lanka reported fewer side effects than those in other countries, suggesting they could better tolerate OCs than the other women. This multicenter study's findings indicates that both Triquilar and Lo-Femenal are effective and safe. In addition, they exhibit good cycle control.