Unintended Consequences of Successful or Partially Successful Interventions
Interventions to reduce mortality and morbidity may be followed by increases in the prevalence of LDD. Examples include the following:
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Improved survival of very low birthweight infants at high risk for LDD may cause the prevalence of disability in the population to increase at the same time that it increases the absolute number of survivors without disabilities.
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Rubella vaccination programs with less than optimal coverage will prevent infections in those vaccinated but leave unvaccinated girls at risk for acquiring rubella infection during their childbearing years (rather than during childhood, as might be expected in the absence of a vaccination program), thereby increasing the risk of congenital rubella infection and disability in the population.
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Newborn screening and treatment for phenylketonuria in infancy and childhood prevent MR, but phenylalanine dietary restriction for women with phenylketonuria during their childbearing years is essential to prevent prenatal neurological damage and MR in their offspring.
