Maternal phenylketonuria--the Irish experience.

The outcome of 48 pregnancies in 18 women with elevated phenylalanine was studied. The women were divided into two groups, diet and non-diet. All the women on diet had severe hyperphenylalaninaemia and only six were on the amino acid mixture at conception. In the non-diet group four women had concentrations of less than 1000 mumols/L and five had severe hyperphenylalaninaemia. Three deaths and one stillbirth occurred in the non-diet group. Microcephaly occurred in 24 children; 11 in the diet group and 13 in the non-diet group. There were five miscarriages in the non-diet group and one in the diet group. Diet is beneficial when started early but planned pregnancies, good motivation and compliance were difficult to achieve in this group of women despite every reasonable effort by the PKU clinic.