ABSTRACT
The efficacy and acceptability of two widely used oral contraceptive tablets, one containing 250 mg levonorgestrel and 50 micrograms ethinyl estradiol and the other containing 150 micrograms desogestrel and 30 micrograms ethinyl estradiol, administered by the vaginal route were compared in 1055 women studied over 12,630 woman-months of vaginal contraceptive pill use. This multicenter clinical trial was performed in nine countries of the developing world by the "South to South Cooperation in Reproductive Health," an organization founded by scientists from the Third World working in the area of reproductive health, and the study was developed and coordinated by one of these centers. The findings of this study confirm the efficacy of both these tablets when administered by the vaginal route. Involuntary pregnancy rates at 1 year of 2.78 for subjects in the levonorgestrel group and 4.54 for subjects the desogestrel group showed no statistically significant difference between the two groups. However, total discontinuation rates of 47.01 for subjects in the levonorgestrel group and 56.33 for subjects in the desogestrel group showed a statistically significant difference between the two groups, and discontinuation rates attributable to prolonged bleeding of 0.6 for subjects in the levonorgestrel group and 3.2 for subjects in the desogestrel group were also significantly higher in the group of subjects using the desogestrel vaginal contraceptive pill. Blood pressure remained at admission values throughout treatment. A statistically significant weight increase from admission values occurred in both groups of subjects.
PIP: Efficacy and acceptability of 2 combined oral contraceptive pills administered vaginally are summarized. This is the 1st collaborative trial published by the South to South Cooperation in Reproductive Health. 1055 women participated in 12,630 cycles, in 9 countries, from June 1988 to May 1991. The pills were commercially available tablets containing 50 mcg ethinyl estradiol and 250 mg levonorgestrel (Schering AG, Sao Paulo, Brazil), or 30 mcg ethinyl estradiol and 15 mcg desogestrel (Organon, Sao Paulo, Brazil). Subjects were aged 17-39 younger and of lower parity from Mexico and Dominican Republic and older from Egypt and China. All had at least 1 pregnancy. 675 participated for 6 months, 470 for 1 year, 364 for 18 months, and 210 for 2 years. The 1-year discontinuation rate averaged 47.01% for the levonorgestrel group and 56.33% for the desogestrel group (p = 0.0061); 2-year discontinuation rates were 48.01% and 69.36, respectively, explained in part by higher involuntary pregnancy rates and prolonged bleeding rates in the desogestrel group. The most common medical reasons for stopping contraception were unplanned pregnancy, vaginal or vulval irritation, nausea, vaginal discharge and headache. Vaginal irritation was reported by 1%, 9 in each group. There were 32 pregnancies, 14 in the levonorgestrel and 18 in the desogestrel group. 17 were in missed pill cycles and the rest were method failures, 6 in the levonorgestrel group and 9 in the desogestrel group. The Pearl index varied from 0 in Nigeria to 12.24 in Mexico, and was 2.45 for levonorgestrel vs. 3.74 for desogestrel. There was a wide variation in discontinuation rates by center: Brazil and China had few, while many women from Dominican Republic, Mexico and Zambia left the study. Bleeding problems were common complaints, more so in the desogestrel group. There were 363 women with intermenstrual bleeding (only once in 80%), 148 with spotting (only twice in 65%). Bleeding duration was significantly less in pill cycles than baseline, pressure. Women gained an average of 1 kg over 2 years, more in the desogestrel group. The pregnancy rate of 2.78 is within the range reported for levonorgestrel rings.
