Non-syndromic
craniosynostosis is multifactorial, and fetal head constraint has been hypothesized as one factor thought to play a role. Data from the National
Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of
birth defects, were used to evaluate associations between four selected factors related to fetal constraint and
craniosynostosis: plurality (twins or higher), macrosomia (
birth weight >4,000 g), post-term gestational age (> or =42 weeks), and nulliparity (no previous live births). Case infants (n = 675) had
craniosynostosis documented either by radiographic evidence or by surgical intervention. Infants with a recognized or strongly suspected single-gene conditions or
chromosomal abnormalities were excluded. Control infants (n = 5,958) had no major
birth defects and were randomly selected from the same population as case infants. Logistic regression was used to estimate odds ratios for the association between these four factors and
craniosynostosis, while adjusting for several covariates. We found that plurality and nulliparity were associated with a twofold increased risk for metopic
craniosynostosis, and macrosomia had almost twice the risk of developing coronal
craniosynostosis. Contrary to our hypothesis, prematurity and low birth weight were also associated with
craniosynostosis. In conclusion, these four constraint-related factors were not found to be associated with
craniosynostosis when all
suture types were combined, though some types of
craniosynostosis were associated with individual constraint-related factors.