Gender difference in achieving rate of maturity of the vesicoureteric junction

Background: Our previous study on the Doppler waveform of the urinary jet at the vesicoureteric junction (VUJ) indicates that there is an active sphincteric mechanism in humans. We have also shown that there are immature and mature patterns of the jet, and the VUJ matures around the age of 4 years. Objective: To determine if there is any gender difference in the time of achieving maturity of the VUJ. Materials and methods: The Doppler pattern of the jets from both ureters was recorded in 273 normal boys and 248 normal girls. The subjects were considered to have immaturity of the VUJ if an immature jet waveform was detected in either ureter. Results: The mean age of VUJ maturity was 4.54 years for the whole population, 4.88 years for boys and 4.34 years for girls. The difference between ROC curves for boys and girls was not significant (P>0.05, simple Z test). Conclusion: There is no significant gender difference in the maturation of the VUJ. Detection of a persistent immature jet pattern beyond the age of maturity might have prognostic implications if there is a concurrent pathological condition related to the urinary tract in children.