The relationship between congenital malformations and preterm birth

Aims: To investigate how congenital malformations (CM) are associated with preterm (PT) births. Methods: A population cohort study analyzed data from the New York State Congenital Malformations Registry to look at live births from the Lower Hudson Valley Region from 2000-2003. ICD9 codes identified all cases and types of CM in addition to cases with multiple malformations. Subjects were categorized into one of three gestational age (GA) groups. Only cases with a known GA at birth were included. Poisson regression analysis established a risk ratio for children born with a CM of being born preterm. Results: The PT birth rate was 11.2% and the CM rate 3%. Children with a CM were more likely to be born PT (RR: 2.20; Cl: 2.01-2.40), moderately preterm (FIR: 1.95; Cl: 1.76-2.15), and very preterm (RR: 3.45; Cl: 2.95-4.04) than term. This relationship was maintained for most organ systems and malformation types evaluated when checked individually. Being born with more than one CM increased the likelihood of being born PT (OR: 1.72; Cl: 1.37-2.15). Conclusions: Congenital malformations in children have a significant impact upon the likelihood of being born PT, and contribute significantly to the degree of prematurity.