Why Deviry 10mg takes minimum 7 to 10 days to trigger period? I am not from medical background, but as per my understanding these hormonal pills increase level of progesterone in our body artificially then once we stop medicine, progesterone level starts to decline. Once it is declined up to a certain threshold, brain send signal to uterus and hence contraction happen and hence period. But why it takes 7 to 10 days time for Deviry 10mg to do this?