Branch LG, Kesty K, Krebs E, Wright L, Leger S, David LR. Deformational plagiocephaly and craniosynostosis: trends in diagnosis and treatment after the "back to sleep" campaign. The Journal of craniofacial surgery. 2015 Jan;26(26). 147-50. PMID: 25569393 [PubMed]
In 1992, the American Academy of Pediatrics discouraged prone sleeping positions because of its association with sudden infant death syndrome. After this was an increased incidence of deformational plagiocephaly (DP).