Women with phenylketonuria: successful management of pregnancy and implications.

Dietary management of five pregnancies in two women (sisters) with classical phenylketonuria (PKU) is described. One child died neonatally of congenital heart disease and one pregnancy miscarried. Of the three surviving children the only physically and mentally normal child, followed up to eight years, was born after a carefully planned pregnancy with strict dietary control preconceptually and throughout pregnancy. One pregnancy treated dietetically from six weeks gestation resulted in a child mentally normal at seven years but born with oesophageal atresia. The third surviving child is microcephalic and mentally retarded but dietetic treatment did not commence till 28 weeks gestation. It is concluded that to be effective, dietary control must be instituted preconceptually.