Evidence versus influence in the WHO procedure for approving essential medicines: misoprostol for maternal health

Misoprostol highlights how when the evidence base is weak, other factors, including expert opinion, can influence the final outcome. Misoprostol was added to the list for prevention of postpartum haemorrhage after concerted lobbying by civil society organisations. Given the weakness of the evidence, it seems that such activities influenced the opinion of the committee. It is not clear why the committee reached a different decision about its use for treatment of postpartum haemorrhage or why it refused to review the evidence after weaknesses were identified.