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Fetal heart rate influence on the pulsatility index in the middle cerebral artery
1Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas.
In 1300 Doppler assessments performed on the fetal cerebral arteries, 5 cases of heart rate deceleration were recorded while studying the middle cerebral artery. There were 3 normal fetuses (mean menstrual age +/- standard deviation: 28.6 +/- 2.1 weeks), one growth-retarded fetus (34 weeks, menstrual age) and 1 fetus with red cell alloimmunization (27 weeks, menstrual age). The magnitude of decline in the heart rate during the deceleration ranged from 44 to 93 bpm (67 +/- 18 bpm). Pulsatility index values were calculated on 44 waveforms and correlated with the heart rate. Linear regression analysis showed a statistically significant inverse correlation between the heart rate and the pulsatility index in the middle cerebral artery of 4 fetuses. These results indicate that heart rate will affect the pulsatility index of the middle cerebral artery.
In 1300 Doppler assessments performed on the fetal cerebral arteries, 5 cases of heart rate deceleration were recorded while studying the middle cerebral artery. There were 3 normal fetuses (mean menstrual age +/- standard deviation: 28.6 +/- 2.1 weeks), one growth-retarded fetus (34 weeks, menstrual age) and 1 fetus with red cell alloimmunization (27 weeks, menstrual age). The magnitude of decline in the heart rate during the deceleration ranged from 44 to 93 bpm (67 +/- 18 bpm). Pulsatility index values were calculated on 44 waveforms and correlated with the heart rate. Linear regression analysis showed a statistically significant inverse correlation between the heart rate and the pulsatility index in the middle cerebral artery of 4 fetuses. These results indicate that heart rate will affect the pulsatility index of the middle cerebral artery.