title: Effects of maternal prenatal smoking and birth outcomes extending into the normal range on academic performance in fourth grade in North Carolina, USA.
abstract: BACKGROUND
  Research has documented the adverse relationship of child cognitive development with maternal prenatal smoking and poor birth outcomes. The potential, however, for maternal prenatal smoking to modify the association between birth outcomes and cognitive development is unclear.
  
  
  METHODS
  We linked statewide North Carolina birth data for non-Hispanic white and non-Hispanic black children to end-of-grade test scores in reading and mathematics at fourth grade (n = 65 677). We fit race-stratified multilevel models of test scores regressed on maternal smoking, birth outcomes (as measured by continuous and categorical gestational age and birthweight percentile for gestational age), and their interaction, controlling for maternal- and child-level socio-economic factors.
  
  
  RESULTS
  Smoking was consistently associated with decrements in test scores, and better birth outcomes were associated with improvements in test scores, even in clinically normal ranges. Test scores increased quadratically with improving birth outcomes among smoking and non-smoking mothers. Among non-Hispanic white children, the magnitude of the association between gestational age and test scores was larger for children whose mothers smoked during pregnancy compared with the non-smoking group. However, among non-Hispanic black children, birth outcomes did not appear to interact with maternal smoking on test scores.
  
  
  CONCLUSIONS
  Maternal prenatal smoking may interact with birth outcomes on reading and mathematics test scores, particularly among non-Hispanic white children. Improvements in birth outcomes, even within the clinically normal range, may be associated with improved academic performance. Pregnancy-related exposures and events exert a significant and long-term impact on cognitive development.
authors.affiliation: School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Anthopolos
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Edwards
authors.forename: Marie Lynn
authors.initials: ML
authors.lastname: Miranda
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002657:Child Development / Q000187:drug effects*; D003071:Cognition / Q000187:drug effects*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008297:Male; D009035:Mothers; D009657:North Carolina; D011247:Pregnancy; D011256:Pregnancy Outcome; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D055815:Young Adult
keywords: achievement; cognition; learning disorders; preterm birth; small for gestational age