OBJECTIVE To assess the effects of meconium-stained amniotic fluid and umbilical cord plasma motilin levels on the development of infantile colic. METHODS One hundred forty pregnant women referred to our department for labor care were enrolled in the study. All subjects were laboring women with singleton, vertex-presenting fetuses, with a gestational age of > or = 36 weeks. After each infant with meconium-stained amniotic fluid was born, the following 2 infants without meconium were selected as controls. Umbilical cord plasma motilin levels were measured in 47 infants with meconium-stained amniotic fluid and 93 infants with no meconium. At the end of the third month of the infants' lives, the development of infantile colic was evaluated. Umbilical cord serum specimens were collected from 45 infants with colic and 95 infants without colic. Statistics included Student's t, chi2 and Mann-Whitney U tests, as appropriate. Multivariate analysis was performed. RESULTS There was no correlation between the presence of meconium-stained amniotic fluid and the development of infantile colic. No association was found between umbilical cord plasma motilin levels and the development of infantile colic. Neonatal intensive care unit admission was found to be a significant risk factor for the development of infantile colic. CONCLUSIONS Meconium-stained amniotic fluid and umbilical cord plasma motilin levels do not affect the development of infantile colic.