blood discharge(spotting) at 30 weeks

Hello mga Mommies. Anyone po na naka-experience ng spotting on their 30th week of pregnancy? What did your OB advised you to do? Na-experience ko kasi ito as I wiped after ko umihi, wala nmn akong naramdaman na any pain or contraction kaya kinabahan ako agad. My OB told me na uminom ng Duphaston 3x a day, and complete bed rest for 7 days. Though hindi nmn nya pinaliwanag sa akin yung reason kung bakit ko naexperience yun. Anyone po na nakakarelate? Share your experience nmn po to enlighten me. Mejo nagwoworry po kasi ako especially kay baby kung okay lang ba sya. Thank you.