Since the American Academy of Pediatrics recommended in 1992 that all infants sleep on their back to reduce the risk of Sudden Infant Death Syndrome, pediatricians have seen an increased number of infants who develop flat spots on the back of their head – a condition called deformational plagiocephaly (DP).

In a study, “Risk Factors Associated With Deformational Plagiocephaly,” published in the December issue of Pediatrics, researchers analyzed a database of more than 20,000 children treated for DP between 1990 and 2007. The database was supplied by Cranial Technologies, Inc., which makes orthotic headbands to treat plagiocephaly.

Researchers found boys were twice as likely as girls to have DP. DP was also more common in firstborn infants, babies with low birth weight, babies who were in the breech and transverse positions in the womb before birth, and in multiple birth infants, specifically dizygotic (fraternal) twins. Independent of these factors, the baby’s sleep position was the best predictor of DP. Study authors suggest future research should attempt to resolve the interactions among environmental factors to help prevent and treat DP.