Outcome at Age 4 Years in Offspring of Women With Maternal Phenylketonuria: The Maternal PKU Collaborative Study

Women with phenylketonuria (PKU) should begin eliminating phenylalanine from their diet completely as soon as they know they are pregnant. In a study of 253 pregnant women, 149 with severe PKU were started on a restricted diet, whereas 33 with mild PKU and 71 with no history of PKU were not treated. By the age of 4, 47% of the children whose mothers received no treatment for PKU or were not adequately treated scored low on tests of intellectual ability. Overall, almost one-third of the children born to women with PKU had social and behavioral problems.