Objectives. To evaluate the relationship between bedwetting and development in infancy.

Methods. Questionnaires concerning micturition habits and development at 3 and 5 years of age were completed by the parents of 157 children who had had their health checked by pediatricians at a group checkup at 3 years of age.

Results. The percentage of bedwetters in whom the frequency of bedwetting was at least once a month was 53% at 3 years of age and 21% at 5 years of age. The prevalent resolution period of bedwetting in infants was 2.5 to 3.5 years of age. The head circumference for boys at birth differed significantly between the bedwetters and nonbedwetters at both ages. Daytime symptoms were more frequent among bedwetters at both ages. Earlier toilet training had no influence on bedwetting at 5 years of age, although it led to earlier control at night at a younger age. Delays in speaking and walking might be factors connected to bedwetting. The prevalence of bedwetting in boys was higher than that in girls. Multiple logistic regression analysis revealed that daytime incontinence and sex were significant factors for bedwetting at 5 years of age.

Conclusions. Daytime incontinence and sex were the significant factors for bedwetting in infancy. Head circumference for boys and developmental delays in speaking and walking might also be important factors.