Doppler sonography of maternal cerebral arteries in pregnancy: side-to-side differences

To study side-to-side differences in blood flow of the common and internal carotid arteries, and the vertebral arteries (VAs) in women with uncomplicated pregnancies as a first step to build a reference values chart.

A total of 155 healthy pregnant women between 20 and 40 weeks' gestation were included. Doppler sonography of the common and internal carotid arteries and VAs was performed on both sides. Parameters measured included diameter, peak systolic velocity, systolic-diastolic ratio, end-diastolic velocity, pulsatility index and resistance index. Statistical analysis was performed using the S-Plus 8.0 program. Normality was determined using the Kolmogorov-Smirnov test. Differences between sides were tested using Student's paired t test, association using linear correlation, and agreement using the Bland-Altman method.

Mean values were equal between sides for all parameters with the exception of the end-diastolic velocity in the VAs. The association and agreement between the measurements taken from the right and left sides were poor. Bland-Altman plots also indicated low agreement between sides. All parameters showed significant right-to-left differences.

Despite the equality between means, right and left flows through the vessels studied differed as there was poor association and agreement.