During early pregnancy, separate areas of the face develop individually and then join together, including the left and right sides of the roof of the mouth and lips. However, if some parts do not join properly, sections don’t meet and the result is a cleft. If the separation occurs in the upper lip, the child is said to have a cleft lip.
A completely formed lip is important not only for a normal facial appearance but also for sucking and to form certain sounds made during speech. A cleft lip is a condition that creates an opening in the upper lip between the mouth and nose. It looks as though there is a split in the lip. It can range from a slight notch in the colored portion of the lip to complete separation in one or both sides of the lip extending up and into the nose. A cleft on one side is called a unilateral cleft. If a cleft occurs on both sides, it is called a bilateral cleft.
A cleft in the gum may occur in association with a cleft lip. This may range from a small notch in the gum to a complete division of the gum into separate parts. A similar defect in the roof of the mouth is called a cleft palate.