Bladder emptying in neonates.

Ultrasound scanning was used to determine whether bladder emptying is complete when a newborn baby micturates. Residual urine was detected in 6 females and 9 males while one female emptied her bladder completely. The residual volume was estimated in 11 subjects and ranged from 3.9 to 13.9 ml. Incomplete bladder emptying cannot be the main factor in explaining the sex incidence of urinary tract infection in neonates.