What happens if baby is head down with low lying placenta in third trimester?

I was wondering if cephalic (head down) in third trimester would not be so good for people with low lying anterior placenta? Won't the baby's head press against placenta as uterus is narrow on the bottom side? All the pictures I see of third trimester baby shows placenta in upper segment and baby nicely tugged upside down. What would it be for people with low lying placenta?