Antenatal antecedents of a small head circumference at age 24-months post-term equivalent in a sample of infants born before the 28th post-menstrual week
Department of Obstetrics and Gynecology
Medical Subject Headings
Adult; Child, Preschool; Cohort Studies; Female; Fetal Growth Retardation; Gestational Age; Head; Humans; Infant, Newborn; Infant, Premature; Male; Maternal Exposure; Microcephaly; Odds Ratio; Placenta; Placenta Diseases; Pregnancy; Risk Assessment; Risk Factors; Smoking
Obstetrics and Gynecology
BACKGROUND: Little is known about the antecedents of microcephaly in early childhood among children born at extremely low gestational age. AIM: To identify some of the antecedents of microcephaly at age two years among children born before the 28th week of gestation.
STUDY DESIGN: Observational cohort study.
SUBJECTS: 1004 infants born before the 28th week of gestation.
OUTCOME MEASURES: Head circumference Z-scores of <-2 and >or=-2, <-1.
RESULTS: Risk of microcephaly and a less severely restricted head circumference decreased monotonically with increasing gestational age. After adjusting for gestational age and other potential confounders, the risk of microcephaly at age 2 years was increased if microcephaly was present at birth [odds ratio: 8.8 ((95% confidence interval: 3.7, 21)], alpha hemolytic Streptococci were recovered from the placenta parenchyma [2.9 (1.2, 6.9)], the child was a boy [2.8 (1.6, 4.9)], and the child's mother was not married [2.5 (1.5, 4.3)]. Antecedents associated not with microcephaly, but with a less extreme reduction in head circumference were recovery of Propionibacterium sp from the placenta parenchyma [2.9 (1.5, 5.5)], tobacco exposure [2.0 (1.4, 3.0)], and increased syncytial knots in the placenta [2.0 (1.2, 3.2)].
CONCLUSIONS: Although microcephaly at birth predicts a small head circumference at 2 years among children born much before term, pregnancy and maternal characteristics provide supplemental information about the risk of a small head circumference years later. Two findings appear to be novel. Tobacco exposure during pregnancy, and organisms recovered from the placenta predict reduced head circumference at age two years.
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Citation: Early Hum Dev. 2010 Aug;86(8):515-21. Epub 2010 Jul 31. Link to article on publisher's site