What Causes Bleeding Even After Taking Duphaston And Ecosprin?

my period cycle is of 32 days ....last date of my period was 5/02/2014...we tried for conception during my ovulation period i.e. on 18 to 22 of this month...while i was waiting for result , on 2 march 2014 i.e. today it started slight bleeding...even though i was taking "duphaspon" from 19 feb & taking "ecosprin" from last three days....so what would be the reason for this problem