A Look at the Physiology of Bed Wetting

The way in which a child’s bladder develops and matures is dependent on three specific things and each of these must take place at the same time.

The three things include the development of what is considered to be “normal bladder capacity”, the development and proper maturation of the urethra and sphincter muscle and the development of both the brain and the neural pathways that connect it in regards to the control of voluntary urination.

It is important to remember that everyone upon being born is incontinent. In other words the bladder of a baby empties on an involuntary basis according to the quantity of urine in the bladder at any given time and other stimuli.

As a baby grows into an infant the “bladder control center” that is to be found in the brain begins to develop as does the muscles in his bladder and his pelvic nerves.

It is a gradual process that takes longer for some children to master than others and also goes along more smoothly for some than others but eventually bladder control becomes a voluntary instead of an involuntary function. 

The bladder capacity of an individual “increases one ounce (30 ml) each year during the first eight years of life.” Females tend to have a bigger capacity for urine volume than do males.

Bladder control during the daytime comes first and then comes nighttime control.

Daytime bladder control is easier to achieve because the person is awake and alert and is able to answer the call of their bladder. On average a child is able to gain control of his or her bladder control in the daytime by the time he is two or three years old.

Bladder control at night happens closer to the age of four, and sometimes five in some children. Girls have a tendency to become successfully trained in using the toilet earlier than boys do. Boys also tend to experience bed wetting at night more than girls do.

Bed wetting before the age of five or six is generally not considered a problem as it is very common and not all children are able to achieve bladder control at night at the same period of time.

As previously mentioned daytime control usually comes first and sometimes nighttime control takes a while to become successful.

After the age of six is bed wetting is present most of the time it is due to a bladder that has not fully matured. In this case time and patience are the best antidotes.

The pathways of nerves that link the bladder and the brain need to develop and the fact is that some children simply have smaller bladders that can accommodate less urine then other children.

Sometimes bed wetting is the result of a child who sleeps so soundly that they aren’t able to tune into the message that the brain is sending for them to wake up and empty their bladder.

Bed wetting can be, but is not often, related to a physical problem such as a bladder infection or diabetes. If bed wetting continues or occurs with increasing frequency past the age of six it is wise to take your child to the doctor for an examination.