Pregnancy complicated by maternal phenylketonuria

Pregnant women who have elevated levels of serum phenylalanine are more likely to have a spontaneous abortion or to give birth to an infant with congenital cardiac anomalies, symmetrical growth retardation, microcephaly and mental retardation than pregnant women with normal levels of this amino acid (1). Nine pregnancies in 7 women were managed in conjunction with the staff of the Children's Hospital, Sydney. In 6 patients, satisfactory serum levels of phenylalanine were attained and 6 offspring are all normal at follow-up, ranging from 15 years to 1 year. The 2 children of the poorly controlled mother were of low birth-weight and both had microcephaly at birth. The poor control of serum phenylalanine was due to poor compliance with the strict dietary regimen. It is concluded that dietary control of serum phenylalanine levels below 600 umol/l in pregnant women with PKU is possible and desirable and may improve perinatal and long-term outcome. This requires close co-operation between paediatrician, dietician, obstetrician and patient. Further data are required to confirm these findings in larger numbers and to provide long-term neurological follow-up.