Acute changes of cerebral venous blood flow in growth-restricted human fetuses in response to uterine contractions.

Abstract

The fetal cerebral venous circulation during acute hypoxic stress provoked by uterine contractions has not been studied previously. The aim of this study was to explore the cerebral venous circulation during an oxytocin challenge test (OCT) in intrauterine growth-restricted (IUGR) fetuses. Doppler recordings of blood flow in the vein of Galen (GV), straight sinus (SS) and transverse sinus (TS) before and during uterine contractions and relaxation were obtained at the same time as electronic fetal heart rate (FHR) monitoring in 44 term IUGR fetuses. The OCT was classified as negative (normal FHR) or positive (late FHR decelerations). Non-parametric statistics were used to test differences between OCT groups. In OCT-negative cases (n = 39), de novo pulsations occurred in the GV, and SS flow velocities increased during contractions compared with basal measurements. There were no significant differences in TS flow. Flow recordings were less often obtained from OCT-positive cases (n = 5), making comparisons with OCT-negative cases uncertain. In uncompromised IUGR fetuses an acute cerebral venous hyperperfusion develops in response to uterine contractions. Pulsations in the GV are detected but are unlikely to be an ominous sign in this situation. The more centrally located TS was less discriminating for acute cerebral venous blood flow changes.