AORTIC, PULMONARY, AND DUCTAL PEAK VELOCITIES IN SYMMETRICAL AND ASYMMETRICAL FETAL GROWTH-RETARDATION - A DIFFERENT ADAPTATION TO PLACENTAL INSUFFICIENCY

Objective: The objective of this study was to investigate the peak vel ocities of the outflow tract of the great vessels in symmetrical and a symmetrical growth-retarded fetuses. Methods: Aortic, pulmonary artery , and ductal peak velocities and the pulsatility index (PI) of the umb ilical artery and of the middle cerebral artery (MCA) were measured by Doppler velocimetry in 31 symmetrically and 48 asymmetrically growth- retarded fetuses within 3 days before delivery. Results: In the symmet rical intrauterine growth retarded (IUGR) fetuses, the peak velocities were not significantly lower than in normal fetuses of comparable wei ght. In the asymmetrical IUGR fetuses, peak velocities were significan tly lower than in normal fetuses (aorta, P < 0.001; pulmonary artery, P < 0.03; ductus arteriosus, P < 0.003). The PI of the MCA in the asym metrical IUGR fetuses was significantly lower than that in the symmetr ical IUGR fetuses, Twenty of 37 elective cesarean sections were perfor med for fetal distress in the asymmetrical group, Intrauterine deaths occurred only in the asymmetrical group with abnormal peak velocities. Conclusion: This study presents evidence that, in asymmetrical IUGR f etuses, the long-standing flow redistribution is associated with a sig nificantly higher risk of impaired ejection velocities from the left a nd right ventricles and intrauterine distress.