The vast majority of infants with plagiocephaly have congenital muscular torticollis (CMT) that forces to sleep over the opposite side.
If the causes (as a persistent torticollis) are not treated properly can lead to asymmetries of the face (basically an obliquity of the midline) during the early years, and if orthopedic correction of the plagiocephaly is not done before the first six months of life may persist into adulthood.
Retrospective and prospective scientific studies indicate that plagiocephaly causes functional problems in 40% of affected and learning and speech problems at 3 years in 25% of those affected. Treat or not plagiocephaly is a decision that parents should take based on these certainties.