Perinatal anterior cerebral artery Doppler flow indexes: methods and preliminary results

Using a standard 5 MHz continuous-wave Doppler system, we were able to record velocities from the anterior cerebral arteries of 20 infants both in utero (at 6 to 10 cm cervical dilatation) and after delivery. In utero tracings were of the same quality as neonatal tracings. Difficulties encountered in the course of the study included abnormal lie, small fontanelle, and excessive caput. Despite these problems our success rate in obtaining good tracings was 80%. Results showed that indexes of cerebral vascular resistance were increased during labor and decreased after birth. However, Doppler indexes of blood flow remained constant throughout the perinatal period. This preliminary report describes the methodology of this new technique. In addition our results demonstrate that in utero intracranial tracings are obtainable and may provide valuable information about cerebral hemodynamics during labor.