title: Gestational age, small for gestational age, and infantile colic.
abstract: BACKGROUND
  Preterm and growth restricted infants may have developmental delays and deviations from normal organ function related to the gastrointestinal tract and the central nervous system. Since both organ systems are hypothesised to be involved in the pathogenesis of infantile colic, a condition characterised by excessive crying during the first months of life, impaired fetal growth and preterm birth may be risk factors for infantile colic.
  
  
  METHODS
  A total of 62,761 liveborn singletons from the Danish National Birth Cohort (1996 to 2002) were studied. Infantile colic was defined according to Wessel's modified criteria based on maternal interview conducted at 6 months post-partum.
  
  
  RESULTS
  A total of 2605 (4.2%) infants were born preterm, 54,441 (86.7%) at term, and 5715 (9.1%) post-term. A total of 4964 (7.9%) infants fulfilled Wessel's modified criteria for infantile colic. The risk for infantile colic increased with decreasing gestational age after adjustment for covariates. The highest odds [odds ratio (95% confidence interval)] was observed for infants born before 32 completed gestational weeks (1.5 [95% CI 1.0, 2.2], reference: 40 gestational weeks). Small for gestational age infants (birthweight below 10th percentile) had an increased odds of infantile colic (1.2 [95% CI 1.1, 1.3]) in all gestational age groups.
  
  
  CONCLUSIONS
  We observed an increased risk of infantile colic in preterm and small for gestational age infants in a large cohort. Our results suggest that the aetiology of infantile colic may be found in the prenatal, perinatal, and neonatal period.
authors.affiliation: Perinatal Epidemiology Research Unit, Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Milidou
authors.forename: Charlotte
authors.initials: C
authors.lastname: Søndergaard
authors.forename: Morten Søndergaard
authors.initials: MS
authors.lastname: Jensen
authors.forename: Jørn
authors.initials: J
authors.lastname: Olsen
authors.forename: Tine Brink
authors.initials: TB
authors.lastname: Henriksen
mesh_terms: D003085:Colic / Q000453:epidemiology / Q000209:etiology*; D003718:Denmark; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008019:Life Style; D008297:Male; D008423:Maternal Age; D009035:Mothers; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
keywords: birthweight; excessive crying; fetal growth retardation; gestational age; infantile colic; modified Wessel's criteria; preterm birth; small for gestational age