If the placenta is lower than normal and the embryo growth is slower by 15 days what could be potential causes and any remedies?

Differnt things. A low lying placenta is a possible problem, but generally it will not give you any particular problem. If it grows across the cervix, it is a placenta previa, and would necessitate a c-section. As to slower than average growth, it is much more disturbing, as a child that is not growing properly has trouble at birth. The most common cause here is smoking. If you smoke, quit.