Hello Ms. Divya,
Grade III placenta at 36 weeks is observed in young mothers. It is more likely to be associated with proteinuric pregnancy induced hypertension
. Since your vital data and other investigations are within normal limits there is no reason to worry. All you have to do is to continue having regular followup. In addition, with rest in left lateral position and reducing the intake of salt and avoiding stress
, you can avert any imminent PIH. Please consult your doctor for further advice. Wish you safe delivery.