Fig. 4From: Zone-specific reference ranges of fetal adrenal artery Doppler indices: a longitudinal studya) Pulsatility index (PI); b) resistance index and c) systolic/diastolic ratio from paired observations of the IAA and MAA. The PI RI and S/D of the MAA were significantly lower than those of the IAA, even after 35 weeks of gestation. IAA, inferior adrenal artery; MAA, middle adrenal arteryBack to article page