Doppler assessment of flow velocity in the uterine artery during pubertal maturation

The aim of this study was to investigate the possible changes in uterine artery flow velocity during puberty and young adulthood. In a cross-sectional study, 133 healthy volunteers aged 6.7 to 25.4 years were investigated. Pubertal development according to the Tanner classification was recorded in each subject. Uterine arteries were visualized by transabdominal color-coded ultrasound. Maximum, minimum and time averaged maximum flow velocities were measured and the pulsatility index (PI) was calculated electronically. When flow velocity was compared between patients at different rates of pubertal development, we found that the average velocity increased from Tanner breast stages I and II to V, followed by a slight decrease in adults (p < 0.0001). The PI varied significantly from stage I to adult (p < 0.0001). The PI was similar in breast stage I, stage II and in adults, with median 4.7 (range 2.7-8.5), 6.1 (range 3.0-7.8) and 4.3 (range 1.9-8.1), respectively. The PI decreased in stages III and IV to 2.6 (1.8-8.4) and 2.8 (1.2-7.9), respectively, whereas stage V was intermediate, at 3.7 (1.1-6.3). The variance of PI was independent of age. In summary, we demonstrated a significant increase in the uterine artery flow velocity during puberty. Furthermore, a significant decline in vascular resistance expressed by the PI was observed in the mid-pubertal period, reflecting increasing blood flow to the rapidly growing uterus.