Determinants of nonsynostotic plagiocephaly: a case-control study.

OBJECTIVE There has been a large increase in reported cases of nonsynostotic plagiocephaly in infants since the adoption of supine sleeping recommendations to prevent sudden infant death syndrome. The objective of this study was to identify and quantify the determinants of nonsynostotic plagiocephaly in infants. METHODS One hundred infants who received a diagnosis of having nonsynostotic plagiocephaly were recruited as case patients and compared with 94 control subjects who were selected from a citywide database of infants. The infants all were aged between 2 and 12 months. Information concerning sociodemographic variables, obstetric factors, infant factors, and infant care practices was obtained by parental interview. RESULTS Case patients were significantly more likely to be male (adjusted odds ratio [aOR]: 2.51; 95% confidence interval [CI]: 1.23-5.16), to be a firstborn (aOR: 2.94; 95% CI: 1.46-5.96), and to have been premature (aOR: 3.26; 95% CI: 1.02-10.47). In the first 6 weeks, they were more likely to have been sleeping in the supine position (aOR: 7.02; 95% CI: 2.98-16.53), not to have had the head position varied when put down to sleep (aOR: 7.11; 95% CI: 2.75-18.37), and to have had <5 minutes a day of tummy time (OR: 2.26; 95% CI: 1.03-5.00). Mothers of case patients were more likely to perceive their infants as less active (aOR: 3.23; 95% CI: 1.38-7.56), to have a developmental delay (aOR: 3.32; 95% CI: 1.01-10.85), and to have had a definite preferred head orientation at 6 weeks (aOR: 37.46; 95% CI: 8.44-166.32). Case mothers were more likely to have no or low educational qualifications (aOR: 5.61; 95% CI: 2.02-15.56), although they were more likely to have attended antenatal classes (aOR: 6.61; 95% CI: 1.59-27.47). CONCLUSIONS Early identification of a preferred head orientation, which may indicate the presence of neck muscle dysfunction, may help prevent the development or further development of nonsynostotic plagiocephaly in infants. Plagiocephaly might also be prevented by varying the head position when putting the very young infant down to sleep and by giving supervised tummy time when awake.