Cleft lip and palate is the most common developmental malformation of the jaw and face, with an incidence of 1‰-2‰ in the population. In China, the incidence of cleft lip and palate in newborns is 1.8 per 1,000. Cleft lip and palate can be divided into syndromic and nonsyndromic cleft lip and palate according to whether it is accompanied by other congenital defects. Non-syndromic cleft lip and palate are common.
It is currently believed that most syndromic cleft lips and palates are seen in some monogenic as well as chromosomal disorders. Non-syndromic cleft lip and palate is currently considered to be a polygenic genetic disorder in which both genetic and environmental factors play an important role. Epidemiological studies have shown that maternal smoking and alcohol use, maternal nutritional status, and the use of anticonvulsant, anticoagulant, and steroid medications during pregnancy increase the risk of non-syndromic cleft lip and palate. In addition, premature rupture of the membranes and living at high altitude are now considered risk factors.
Ultrasound during pregnancy can diagnose most fetal cleft lips, but some fetuses with small cleft lips and prenatal ultrasound diagnosis of cleft palate are difficult.