Hi I Am 24 Weeks Pregnant. I Don't Understand The

Hi I am 24 weeks pregnant. I don't understand the meaning of anterior placenta grade 2 on my last ultrasound, it was also says that i have adequate amniotic fluid (which I guess nothing to worry about) but I am more concern of the placenta because my first baby died due to placental insufficiency.. I am just worried with my 2nd baby.. other details he WEIGHTS approx. 642.89 grams HEART RATE 156 bpm. Hope you can answer my inquiry. Thank you.