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17695

The Physiological Micturition of the Fetuses 19-40 Weeks of Gestation. Normal Urodynamic Parameters

Saturday, October 20, 2012
Grand Ballroom A/B (Hilton Riverside)
Liudmila A. Deryugina, Pediatric Surgery, Saratov State Medical University named after V.I. Razumovsky Scientific Research Institute of Fundamental and Clinical Uronephr, Saratov, Russia and Dmitry A. Morozov, Pediatric Surgical, Saratov State Medical University named after V.I. Razumovsky Scientific Research Institute of Fundamental and Clinical Uronephr, Saratov, Russia

Purpose

to represent  the lower urinary tract urodynamic parameters of the fetuses between 19 and 40 weeks of  gestation under the physiological circumstances.

Methods

" Prenatal  ultrasound cystometry with natural filling" - the method for dynamic control  of  fetal lower urinary tract. During serial ultrasound measurements of fetal bladder volume  we registered bladder cycling in graphical format where the bladder volume is plotted against the observation time.

 Urodynamic characteristics:    maximal bladder volume, bladder cycling, residual volume of the bladder reflected   the capacity, reservation and micturition function  of the bladder. Fetal urine production was calculated using the increase volume bladder during the observation time.

56 prenatal ultrasound  fetal urodynamic investigations  were performed during normal  pregnancy  of the fetus in 19-40 weeks of gestation. No complication of the pregnancies, normal antenatal period,  normal neonatal parameters and postnatal period.

Results

Normal  urodynamic parameters of the fetuses between 19 and 40 weeks of  gestation are represented in the table.

Urodynamic parameters

18 – 22

weeks

(n = 18)

23 – 26

weeks

(n = 15)

27 – 30

weeks

(n =11)

31 – 33

weeks

(n = 12)

34 – 36

weeks

(n =1 9)

37 – 40

weeks

(n = 9)

V max

bladder volume(ml)

М = 0,88

δ = 0,27

m =± 0,07

M = 2,55

δ = 1,34

m =± 0,4

M = 8,07

δ = 3,09

m =±0,97

M = 12,28

δ = 5,4

m = ±1,58

M = 21,7

δ = 4,9

m = ±0,1

M = 27,03

δ = 4,26

m =± 1,4

T (min)

micturition cycling

M =16,92

δ = 3,94

m =± 1,09

M =25,7

δ = 5,59

m = ±2,3

M = 30,3

δ = 5,3

m = ±1,6

M = 33,5

δ= 5,3

m = ±1,9

M = 37,5

δ = 5,3

m = ±1,4

M = 42,42

δ = 9,82

m =± 3,71

%

(residual urine)

M = 8,14

δ= 3,6

m =± 1,01

M = 9,8

δ = 4,54

m =± 0,94

diuresis

ml/kg/h

M = 9.93

δ = 4.13

m =± 1,14

M =9,63

δ = 3,34

m =±1,03

M =9,93

δ = 7,7

m =±3,2

M=15,15

δ =8,79

m =±2,58

M=17,57

δ = 7,02

m =±2,02

M =12,95

δ =4,34

m =±1,64

The gradual increase of capacity, bladder cycling, hourly urine production correlates 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.  We had 10 occasions to measure one-step voiding urine flow: 37 weeks fetus             urine flow  -  1.8 ml/sec

The hourly urine production  refleced he physiological polyuria. The parameter of the 38-weeks fetus is 17 ml/hour/kg is 4-3 more than newborn baby.

Conclusion

The normal lower urinary tract hydrodynamic parameters base further investigations in the fields of antenatal urology.