CONTINUOUS DETERMINATION OF UMBILICAL ARTERY FLOW PARAMETERS DURING FETAL BRADYCARDIA USING COMPUTERIZED ANALYSIS OF DOPPLER WAVE-FORMS

Umbilical artery flow curves were obtained by Doppler ultrasonography before, during, and after episodes of fetal bradycardia in the active stage of labor in 6 women. Between 126 and 1,607 Doppler wave forms we re analyzed for each patient. During the periods of bradycardia all th e umbilical artery resistance flow parameters increased (p < 0.00001). The increase in resistance did not precede the change in heart rate. This study presents an accurate and reproducible method for continuous evaluation of the changes in the impedance of fetal blood flow during fetal heart rate changes, thereby enabling detailed assessment of cir culatory disturbances occurring during labor and delivery.