The relation between plasma urate and placental bed vascular adaptation to pregnancy.

Placental bed biopsies were obtained at caesarean section from 34 women. Their plasma urate was directly related to maximum mean arterial pressure and inversely to adjusted birthweight; but it was related most closely to the histological appearances of the spiral arteries in the placental bed. Nine women had physiological changes in the spiral arteries: their mean urate (233, SD 28.9 mumol/l) was significantly (P less than 0.001) lower than the mean urate in those who did not have adequate physiological changes (339, SD 90.3 mumol/l) or that in the nine women who had atherosis (397, SD 153.2 mumol/l). Raised plasma urate appears to be better related to maternal vascular pathology than to the clinical condition or infant birthweight.