How do cleft lip and palate develop?

Cleft Lip / Palate: The facial features that form the lip and palate fuse in weeks six through eight of gestation. When this process fails due to genetic or environmental factors, a cleft lip or palate result.

Failure of fusion: There are essentially three layers in the developing embryo and it is felt that failure of the middle layer to advance and fuse in the face (from the frontonasal process of the bronchial arches) maybe responsible. While socioeconomic factors and nutrition play a role, genetic factors are also contributory.

Failure to develop: Cleft lip and palate develop or rather, fail to develop in utero. When the fetus is just around two months old, protuberances start in the head area and coalesce to form the face. If these protuberances fail to fuse, a cleft develops. A cleft can develop in many different sites but the most common are in the upper lip and upper palate. 1 in 700 babies will have a cleft.

Birth defect: The formation of a face is a complicated process involving fusion of different tissues and cell types. Cleft lip and/or palate are caused by failure of those processes to proceed as they normally do. There is a spectrum of abnormailities that fall into this category.