Micturition Studies in Infants and Children:Normal Urinary Flow

The urinary flow was studied in 216 boys and 180 girls, aged 3 days to 16 years. the individual flow pattern was fairly constant. There were considerable variations between different individuals. the ranges of different flow variables at different micturition volumes are given. With increased micturition volume the flow curve showed a plateau in the age group 4-13 years. This plateau seems to be characteristic for children. the maximum flow was positively correlated to the volume of voided urine, as in adults. in girls no difference between age groups could be demonstrated as regards increase in maximum flow with volume. in boys 0-4 years the increase of maximum flow with volume was more pronounced than in boys aged 4-16 years. Girls 4-16 years showed a more pronounced increase of maximum flow with volume than boys of the same age group—above 70 ml volume their mean maximum flow was on a higher level. An attempt was made to correlate the maximum flow with height, weight, body surface and age, respectively. the coefficients of correlation were small and about the same for all the parameters. Thus, growth seems to have little influence on maximum urinary flow, which is mainly related to the voided volume. There is a slight tendency for maximum flow to increase during growth to reach a level just below the values reported for adults. Psychic factors seemed to have surprisingly little influence on micturition provided attention was paid to the specific demands of the paediatric age group. Abdominal straining was not used during micturition by normal children.