A prospective double-blind, randomized trial was conducted in two biomedical hospitals and 1 Tibetan hospital in Lhasa, Tibet, to test the hypothesis that 600 μg oral misoprostol is more effective than ZB 11 in reducing the frequency of an adverse primary outcome.The trial began in August 2005 and to date 1131 women have been screened for study participation, 673 were eligible and 438 randomized.All 3 hospitals are randomizing patients, although cultural differences in the acceptance of traditional Tibetan medications have affected consent rates, which vary from 52% to 92%.The hospitals have properly reported adverse events, used the blood collection drape, completed data forms and keyed and transmitted data to the data center.Based on current rates, enrollment is expected to be completed by Apr., 2007.