Epidemiology of inguinal hernia in preterm neonates.

We have studied the epidemiology of inguinal hernias in preterm infants. Inguinal hernias occur with increased frequency in infants less than or equal to 32 weeks' gestational age or less than or equal to 1,250 g birth weight. Among infants less than or equal to 32 weeks' gestational age, intrauterine growth retardation significantly increases the risk for development of inguinal hernias, especially in male infants. Our data demonstrate a previously unrecognized association between neonatal inguinal hernia and intrauterine growth retardation.