Why do you need presentation scan?
The scan checks the baby’s position. Babies keep moving around in the womb. The position begins to matter in the 37th week as the due date is drawing near. It will mostly have to be a caesarean delivery if the baby is in the breech position (head up and bottom down). A normal delivery is possible in some breech positions. The doctor will be able to decide on the same after seeing the scan.
Secondly, the scan also checks the position of the placenta. If the placenta was in a lower position at the time of the 20-week scan, it is likely to have moved up out of the way of the cervix by the third trimester scan. If the placenta still persists to be close or over the cervix, it is called placenta praevia. In such cases, a caesarean section becomes necessary.
Hence, presentation scan is very important for the doctor to determine the mode of delivery ahead of time. Also it is to better prepare the mother before the arrival of her newborn.