Maternal phenylketonuria: the outcome of pregnancy.

This report documents the outcome of two pregnancies is a woman with phenylketonuria (PKU) who was treated with a low phenylalanine diet before conception and during pregnancy. Her first pregnancy resulted in an abortion at 17 wk. During the second pregnancy the patient was unable to maintain the right diet consistently, and her blood phenylalanine levels in the first and second trimester were elevated. This pregnancy ended in the birth of a growth retarded microcephalic infant after an amenorrhea of 42 wk. The infant has maintained a normal growth velocity below the tenth percentile, and has not shown signs of mental retardation.