[Efficacy and safety of a combined oral contraceptive containing drospirenone 3 mg and ethinylestradiol 20 µg in a 24+4-day regimen in China].

Objective: To assess the efficacy, bleeding pattern, cycle control and safety of a combined oral contraceptive (YAZ) containing drospirenone 3 mg and ethinylestradiol 20 µg in a 24+4-day regimen in China.

Methods: This is a multi-center, open, one-label study. Healthy females aged 18-45 years received YAZ for 13 cycles. Following-ups were scheduled during the treatment phase on Day 12-19 of Cycle 1, 4, 7 and 10 and 10-17 days after completing the study. The efficacy variables were the number of unintended pregnancies, bleeding pattern and cycle control. The safety variables were adverse events (AE), lab examinations, physical and gynecological examinations, vital signs and body weights and questionnaires.

Results: Four pregnancies occurred among 675 women for 603.78 women-years, resulting in a Pearl index (PI) of 0.7 and adjusted PI of 0.6. The cumulative 1-year pregnancy rate was 0.66%. The mean number of bleeding/spotting days was (26.3 ± 12.4) days in reference period 1 and (15.4 ± 5.5) days in reference period 4. 94.2% (582/618)- 96.8% (538/558) subjects experienced scheduled bleeding. The mean duration of scheduled bleeding decreased from (5.9 ± 3.2) to (5.0 ± 1.6) days. The percentage of women with intermenstrual bleeding decreased from 14.5% (90/621) at Cycle 1 to 2.3% (13/558) at Cycle 12. The common AE relating treatment include nausea (3.4%, 23/675), breast tenderness (1.2%, 8/675), dizzy (1.2%), vagina bleeding (1.2%). No serious AE relating treatment occurred. 85.6% (542/633) subjects were satisfied or very satisfied with the study treatment.

Conclusion: YAZ is highly effective, acceptable and safe for Chinese women.