The Effect of Full and Empty Bladders on Uterine Artery Doppler Parameters in the First Trimester

Background: The presence of increased resistance in uterine artery Doppler measurements is associated with preeclampsia and other adverse pregnancy outcomes. Therefore, this study aimed to evaluate whether a full or empty bladder affects uterine artery Doppler results. Methods: This study included 213 women with singleton pregnancies between 11–13 weeks. The first measurement for bilateral uterine artery Doppler parameters was performed while the patients experienced a full bladder, while the second measurement was conducted immediately following urination. Results: Uterine artery notching presented statistically significant results when the bladder was evaluated as full and empty. While the mean values calculated for the left uterine artery pulsatility index were 1.82 ± 0.04 before micturition, this value was calculated as 1.74 ± 0.04 after micturition (p = 0.011). The mean value for the right uterine artery while the mean value was 1.85 ± 0.042 before micturition, it was calculated as 1.81 ± 0.041 after micturition (p < 0.001). Uterine artery resistance indices were also statistically different before and after micturition. The mean values calculated for the left uterine artery resistance index were 0.77 ± 0.008 before micturition and 0.74 ± 0.007 after micturition (p = 0.003). For the right uterine artery, it was calculated as 0.76 ± 0.008 before micturition and 0.75 ± 0.01 after micturition (p = 0.047). Conclusions: Although there are minimal studies on this subject in the literature are limited, physiological principles and the results of the present study show that emptying the bladder before arterial Doppler evaluation of spaces such as the abdominal compartment, will provide more accurate results.