Objective: To establish reference values of anterior cerebral artery (ACA) Doppler indices in normal fetuses during the period between 20- and 37-weeks’ gestation.

Materials and Methods: A prospective, cross-sectional study was conducted on low-risk singleton pregnancies with healthy fetuses. The ACA Doppler spectral waveforms were obtained using transabdominal Doppler sonography, just after the origin of the ACA from the internal carotid artery in the same plane as the middle cerebral artery. The putative normative data were analyzed and constructed for the median, fifth, and ninety-fifth percentiles of ACA Doppler indices for each gestational week.

Results: Three hundred fetuses were measured for ACA Doppler indices. The pulsatility index (PI) and resistance index (RI) continuously increased from 20-weeks’ gestation until a period of relative stability at 28- to 32-weeks, followed by a gradual reduction thereafter. Peak systolic velocity (PSV) showed a constant increase with advancing gestational age. A quadratic analysis was performed to construct curve-fitted percentile charts for each of these variables.

Conclusion: Reference values of the fetal ACA Doppler indices are constructed. This nomogram may be a useful tool for early detection of the brain-sparing effect in growth-restricted fetuses.

Keywords: Doppler indices, Anterior cerebral artery, Reference values

Received 7 Jan 2019 | Revised 1 Mar 2019 | Accepted 15 Mar 2019