When there's a crease or waistband in the middle of the baby bump, the belly appears to be divided into a top and bottom half, then it's known as a B belly.  B belly in pregnancy is more common in people with more weight, and it doesn't matter if they have a longer or a shorter torso. Many other factors play in forming a B belly, such as height, weight, and muscle and bone structure.  A B belly also makes people conscious of their belly size and shape because in mainstream media, what they promote is a well-rounded pregnant belly. B belly shape doesn't mean you don't have a normal and healthy pregnancy.