Repeated adverse fetal outcome in pregnancy complicated by uncontrolled maternal phenylketonuria

Phenylketonuria in pregnancy carries with it an increased risk of spontaneous abortion and development of a fetus that is affected by the maternal phenylketonuria syndrome. This syndrome is characterized by low birthweight, congenital heart disease, microcephaly, childhood growth failure, and cognitive impairment. It is the result of the hyperphenylalaninemia that accompanies the phenylketonuric state, and may therefore be avoided by maintaining maternal serum phenylalanine levels within the normal range. Phenylalanine is an essential amino acid and may be controlled by dietary manipulation. Presented here is a case history of a woman with phenylketonuria who was unable to satisfactorily control her serum phenylalanine levels in each of her three pregnancies. All three children were adversely affected by the fetopathy of the maternal phenylketonuria syndrome, each with evidence of growth failure and impaired neurodevelopment. This patient illustrates the difficulties that may be encountered when providing obstetric care to the woman with phenylketonuria who is not able or not willing to restrict her dietary intake of phenylalanine. The discussion includes consideration of management strategies, including dietary therapy and legal intervention.