Hy Im 33 Years Old, Mother Of 2 Kids By

hy im 33 years old, mother of 2 kids by natural delivery. now im 6 weeks pregnant, last year i had to go for DNC for no heartbeat and spotting. this time all are ok.. hear beat as well as no spotting.. though my dr suggest me to take Gestrenol (5 mg) tab 3 times a day for 1 month.. Noted: I have Hypothyroidism for last 10 years, but my 2 kids are totally normal.
now my question is, Is't must to take this tab? or i can avoid? is there any impact for taking or not taking this?
thnx
Jes