Plagiocephaly refers to the flattened, asymmetrical, or misshapen skull of infants due to positional molding from external forces. While still in the womb, the baby’s head may be ‘stuck’ in a certain position (more common in twin pregnancies). After birth, the baby may be spending a lot of time lying on his back, or having their head turned favoring a side. A baby’s skull is soft and pliable, so it may flatten during the first few months of life.