Micturition of the Fetuses 19-40 Weeks Of Gestation of the Physiological Circumstances

Abstract

Purpose The antenatal investigation of the fetal urinary tract abnormalities bases on the normal urodynamic parameters of lower and upper urinary tract. The aim of the study is to represent the lower urinary tract urodynamic parameters of the fetuses between 19 and 40 weeks of gestation under the physiological circumstances. Material and Methods “Prenatal ultrasound cystometry with natural filling” - the method that is based on the new methodological approach of dynamic control of fetal lower urinary tract with the help of the volume based principle of monitoring of activity of a bladder during micturition cycle. 56 prenatal ultrasound fetal urodynamic investigations were performed during normal pregnancy of the fetus in 19-40 weeks of gestation. Results Urodynamic characteristics are represented by: maximal bladder volume, time between two successive acts of voiding, residual volume of the bladder, that reflect the capacity, reservation function of the bladder, micturition frequency, hourly urinary production. The gradual increase of capacity, bladder cycling, hourly urine production correlate with gestational age and fetal weight during normal pregnancy. One-step voiding complete emptying of the bladder at 19-23 weeks of gestational is replaced by two-three-steps of voiding incomplete emptying of the bladder (residual urine ≤15%) at 36-40 weeks. The equivalents of fetal behavioral reactions demonstrating fetal control over urination has noted like increasing fetal physical activity followed by urination or preliminary bladder emptying. Conclusions The normal lower urinary tract hydrodynamic parameters of the control group are absolutely necessary for comparing the same parameters in cases of fetal urinary tract abnormalities or complicated pregnancy.