Objective A review of evidence was conducted to assess the safety, effectiveness and continuation of once-a-month contraceptive pills. Methods Papers were identified by electronic searches in Chinese and international databases and manual searches of Chinese journals and index of family planning literature. Data on pharmacokinetics, clinical performance and laboratory examinations were extracted from 17 papers of mixed quality on pills containing quinestrol 3 mg and norgestrel 12 mg (Quin-Ng) or levonorgestrel 6 mg (Quin-Lng) used by women in China. Results Quin-Lng pills gave steady-state serum levels of ethinylestradiol between 0.20–0.25 and 0.15 ng/mL. The 1-year perfect use pregnancy rate was 1.1 per 100 women-years. Nausea and increased leukorrhea were common; bleeding control was good. Hypertension developed in 5.8% of Quin-Ng pill users during the first year of use. For Quin-Ng and Quin-Lng once-a-month pills, 1 year continuation rates were 73.6 and 82.1 per 100, respectively. Conclusions Lack of good quality data prevents confident assessment of the safety and efficacy of once-a-month pills. Short-term safety information indicates a high incidence of bothersome side effects and hypertension. The high monthly estrogen and progestogen doses raise questions about the safety of the once-a-month pills.
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