What is post placenta?

Often is will refer to the location of the placenta in the uterus. A post placenta can mean that the placenta is located at the back, or posterior, of the uterus... which would be a normal location.

Was anything mentioned about it?

It can also mean that the placenta is in front of the baby in relation to the cervix... also commonly referred to as placenta previa. If it's early in the pregnancy, usually it will correct itself and the placenta will raise allowing for normal vaginal delivery.