Development of bladder and bowel control from 6 months to 6 years was investigated in 140 preterm children and a control group of 349 healthy term children. Structured parental interviews and neurodevelopmental assessments were carried out when the child was 1, 3, 6, 9, 12, 18 and 24 months, and at yearly intervals thereafter. Even though preterm children were put on the potty at significantly earlier ages and significantly more frequently than term children, they expressed their need for evacuation and attained day and night bladder and bowel control at the same corrected age as term children. Initiation and intensity of toilet-training were not significantly correlated with the development of bladder and bowel control. Gestational age, being too small for gestational age, adverse perinatal conditions and mild to moderate neurological impairment did not affect the occurrence of the child's initiative and the development of bladder and bowel control. Neither developmental and intelligence quotients at the age of 1 to 3 years nor the socioeconomic status of the families influenced the age at which the child became clean and dry. Girls were significantly more advanced in expressing their needs and gaining bladder and bowel control than boys in both the preterm and term groups.
Conclusion: Development of bladder and bowel control is largely a maturational process which cannot be accelerated by an early onset or a high intensity of training. It is not affected by prematurity, adverse perinatal events or mild to moderate neurological impairment, nor is it related to psychomotor development or actual Swiss socioeconomic conditions.