title: The voiding pattern of healthy preterm neonates.
abstract: OBJECTIVE
  To elucidate further the maturation of voiding habits from gestation to infancy we investigated the free voiding pattern of healthy preterm neonates.
  
  
  METHODS
  We evaluated 11 male and 8 female healthy preterm newborns at a mean of 32 weeks after cessation of menstrual flow (postmenstrual age). Assessment was done in the neonatal ward using 4-hour voiding observation, a method described previously in studies of free voiding pattern of full-term newborns.
  
  
  RESULTS
  The voiding pattern of male and female preterm neonates was characterized by 1 void per hour and a mean voided volume of 53% of bladder capacity with 58% frequency of interrupted voiding. Residual urine was increased but varied during observation (mean 11% bladder capacity) and was 0 after at least 1 void during 4 hours in 14 of the 19 subjects. Two-thirds of all voiding occurred during sleep, whereas a third of the newborns showed signs of arousal with a mean awake time of only 17 minutes.
  
  
  CONCLUSIONS
  The voiding pattern of preterm versus full-term subjects is characterized by an increased number of interrupted voidings, further indicating that these voidings represent immature behavior of detrusor-sphincter coordination. Also, the high number of voidings during sleep suggest a more immature pattern for preterm newborns.
authors.affiliation: Department of Pediatric Surgery, University Hospital, Ostra, Göteborg, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Sillén
authors.forename: E
authors.initials: E
authors.lastname: Sölsnes
authors.forename: A L
authors.initials: AL
authors.lastname: Hellström
authors.forename: K
authors.initials: K
authors.lastname: Sandberg
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008297:Male; D014554:Urination / Q000502:physiology*