An original sample of 848 women was increased and 967 consenting women were randomized (1:1) to a ZB11 or misoprostol arm. Since ZB 11 and misoprostol must be administered at different times, participants will receive either active ZB 11 or corresponding placebo at full dilation and active misoprostol or corresponding placebo immediately following the birth of the baby. The effectiveness of the study drug will be estimated by the postpartum blood loss that will be measured on all enrolled women with a blood collection drape.