Pregnancy in a woman with maple syrup urine disease.

We present the favourable outcome of a pregnancy in a woman with maple syrup urine disease. Keeping the maternal plasma levels of the branched-chain amino acids between 100 and 300 mumol/L is compatible with delivery of a normal infant. Leucine tolerance increased progressively from the 22nd week of gestation from 350 to 2100 mg/day. The risk of metabolic decompensation in the postpartum period can be minimized by careful monitoring of the mother after delivery.