Fetal Stress as a Cause of Fetal Brain Damae

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It has been reported that umbilical cord occlusion is closely related to perinatal brain damage. We hypothesized that repeated umbilical cord occlusions cause fetal cardiac dysfunction, which is possibly related to brain hypoperfusion and injury. The purpose of this study is to investigate the effect of repeated umbilical cord occlusions on cardiac functions in fetal sheep.We inserted a conductance catheter into the left ventricle of the heart under ultrasound guidance to record pressur-volume curves of the left ventricle of the heart in 11 near-term fetal sheep. Umbilical cord was completely occluded five times for 60 seconds, five times for 90 seconds and five times for 120 seconds.Umbilical cord occlusions reduced stroke volume significantly throughout the experiments. During intervals of 90 seconds occlusion, fetal heart contractility and cardiac output increased Significantly compared with the control levels. However, stroke volume decreased significantly during intervals of 120 seconds occlusion. It is speculated that these changes in fetal cardiac function could be related to hypoxia, acidosis, and catecholamine secretion induce by repeated cord occlusions.