Two successive pregnancies in a woman with xanthinuria: unexpected increase in serum uric acid levels.

Two successive pregnancies were observed in a patient with xanthinuria. In each of them, maternal serum uric acid (SUA) level rose progressively during the third trimester, reaching a subnormal value just before delivery. The level of UA was slightly higher in arterial cord blood than in maternal blood. There was no difference between levels in arterial and venous cord blood. It is suggested that xanthine oxydase may be present in the placenta.