Girls, could you please tell me? Since I've been pregnant, I've been t…

Girls, could you please tell me? Since I've been pregnant, I've been taking Utrozhestan. The dosage is 100 now, the doctor says it will be reduced. What I'm curious about is, do they just stop it all at once or gradually, like day by day, maybe he'll have to take it every day? I don't know what to do, should I buy a whole pack or half of one?