restricted uterine blood flow

Anjali

I am 21 weeks pregnant with first...restricted uterine blood flow, is that risky, and if i take blood thinner would it harm my baby as i have very low placenta...and doctor said she cant prescribe blood thinner till 24weeks and i have checked with another doctor she said i can take from now on also and that too 150 gm...isn’t that too heavy...??