RESUMEN
OBJECTIVE: This study was undertaken to determine whether is there a difference in the middle cerebral artery peak systolic velocity (MCA PSV) between active and resting behavioral states in healthy fetuses aged 30 to 32 weeks. METHODS: MCA blood flow was measured by pulsed Doppler sonography 3 times during each fetal behavioral state (active and resting). The average during active state was compared during the resting state. Statistical analysis was performed by paired t test. RESULTS: During the fetal active state, there was a significant increase in the mean PSV (51.59 cm/s vs 46.95 cm/s, P < .0001) and mean end-diastolic velocity (9.59 cm/s vs 7.98 cm/s, P=.0015), and a significant decrease in the mean pulsatility index (PI) (2.07 vs 2.19, P=.0226) and the mean resistance index (0.83 vs 0.85, P=.0481). CONCLUSION: Healthy preterm fetuses have a significantly higher MCA PSV during the active state. Activity state should be considered when interpreting MCA Doppler indices.