Resuscitation at birth associated with low IQ score.

Infants who undergo resuscitation at birth are more likely to have a low IQ score later in childhood than those who do not, and resuscitated infants with asymptomatic encephalopathy account for a greater proportion of affected adults than those with encephalopathy, according to a study published online April 21 in The Lancet.

David E. Odd, MD, of the University of Bristol in the United Kingdom, and colleagues conducted a study of 11,482 infants, of whom 10,609 formed the reference group who did not have symptoms of encephalopathy, did not undergo resuscitation, and did not require further neonatal care; 815 who were resuscitated but were also asymptomatic for encephalopathy and needed no further neonatal care; and 58 who were resuscitated and also received neonatal care for encephalopathy.

Resuscitation was positively associated with an increased risk of low IQ score at the age of 8 years; while being asymptomatic for encephalopathy contributed 3.4% to the population attributable risk fraction of a low IQ score, and encephalopathy added 1.2% to the risk, the investigators found.

"These findings are consistent with a cerebral injury of sufficient severity to delay respiration, but insufficient to cause obvious symptoms of encephalopathy," the authors write. "Our results support the idea of a continuum of reproductive casualty.

Odd DE, Lewis G, Whitelaw A, et al. Resuscitation at birth and cognition at 8 years of age: a cohort study. The Lancet, Early Online Publication, 21 April 2009doi:10.1016/S0140-6736(09)60244-0.