Flow patterns in newborn infants

Abstract

Purpose To assess the normal voiding flow patterns of newborn males. Material and methods The parents of 30 newborn healthy male infants (gestational age median 40 + 2 weeks) agreed to participate in a 4-hour-observational study of ultrasound probe flow measurements (median age 76 hours). The data of twenty-four infants was available for analysis, four did not void during the observation period and in two the data was not available due to technical errors. Flow patterns were assessed according to the definitions of the International Children's Incontinence Society (ICCS) definitions. Results A total number of 59 voidings were recorded. Flow curves were bell-shaped in 55,9%, interrupted in 18,6%, staccato in 8,5%, tower in 5,1%, plateau in 5,1% and what we coined Spike-Dome shaped in 6,8% of all voidings. The latter occurred in four infants. The mean average flow rate was 1,3 ml/sec and the mean maximum flow rate was 3,0 ml/sec. The infants voided a mean 0,6 times per hour with a mean of 15 ml per micturition. Conclusions Newborn infants have small voidings and the voided volume depends on the extent to which breast feeding has been established. Voidings were much more dyscoordinated than in older infants. In four children we found a spike-dome flow pattern which might represent a relaxation of the pelvic floor (and emptying of the urethra) before detrusor contraction is initiated. The tower pattern seen in 3 infants, probably represents part of the same phenomenon. This study closes the gap between our observations (Olsen et al. J Urol;171: 2660-2663) of dyscoordinated voiding in late fetal life in animal studies and the observations made by others in older infants and boys(Wolffenbuttel et al. J Urol ;166:1058-1061; Bower et al. J Urol;171:2657-2659).