Management of maternal phenylketonuria: an emerging clinical problem.

The children of untreated phenylketonuric women have a significantly higher mortality and morbidity than average. The success of neonatal screening for phenylketonuria (PKU) means that an increasing number of healthy intelligent women with PKU are reaching childbearing age and will create a new therapeutic problem for physicians and obstetricians in the next decade. This unit managed six mothers with PKU and treated three of them with diets throughout four pregnancies. The treatment and outcome was assessed in relation to those in other reported cases. Although treatment was beneficial in the four pregnancies studied directly, in all the reported cases the outcome of treatment varied considerably and was not clearly related to any one factor such as onset of treatment or the type of PKU. It is therefore not possible to give confident advice about the management of such cases. Since the number of women at risk will reach a peak in 10 years' time there is an immediate need for a well-planned prospective study of this problem.