Mama, this is really something you need to ask your OB directly kasi siya lang ang makikita ng ultrasound mo at makakasabi ng accurate grade ng placenta mo, iba-iba talaga depende sa individual pregnancy! A few of us mums always make sure to bring our ultrasound results sa check-up para tanungin agad ang doctor kung normal pa ba, kaya go lang sa next appointment mo or call the clinic if worried ka now. They'll explain everything and make sure baby is okay. Take care!