Taking Duphaston until when?

Baka meron po dito same experience as mine. I have first born but died 5 days after birth, due to being premature at 8 months old. Ngayon, 8 weeks pregnant ako pero advise ng OB ko na mag take ng Duphaston until 20 weeks kaso ang pricey kasi 85 pesos each tapos 2 times a day😅. Okay lang kaya kung 1 time a day ko na lng inumin wala naman akong spotting or kahit anong nararamdaman, okay naman din result ng TransV ko. TIA #duphaston #pregnacy