Bladder function in preterm and full-term infants--free voidings during four-hour voiding observation.

The purpose with the present review was to characterise bladder function in healthy preterm and full-term infants from findings in studies using the four-hour voiding observation. Characteristics of the free voiding pattern were very similar in preterm and full-term infants. The frequency of voidings was once an hour, bladder volume inducing voiding varied, infants often woke up before voiding and the bladder was not completely emptied at every voiding. Furthermore, interrupted voidings interpreted as a detrusor-sphincter dyscoordination, were seen and were clearly an immature phenomenon since the frequency was high in the preterm infants and then decreased. Concluding these findings the voiding pattern seems to be immature early in life and there is distinct evidence for a connection to the CNS already in the preterm infant.