Cleft lip and palate is caused by a disruption of the embryo during the first 12 weeks of development, which prevents normal embryonic development and fusion between embryonic tissues. Common causes include genetic and environmental factors, which may be caused by a single cause or a combination of causes. Genetic factors: It has been confirmed that fetuses with a family history of cleft lip and palate have a higher chance of developing cleft lip and palate, which can develop alone or may be combined with malformations of other body parts. Second, environmental factors: 1, vitamin deficiency: pregnant women frequent vomiting or paranoid diet resulting in vitamin deficiency, unable to supply the fetus with the necessary nutrients, fetal stunted development, may cause cleft lip and palate; 2, mental stimulation: pregnant women during pregnancy mental instability, often worry, anxiety, irritability, fear and other adverse emotions, may cause increased secretion of adrenocorticotropic hormone, preventing the normal fusion of the embryo, causing Fetal cleft lip and palate; 3, viral infections or drugs: early pregnancy, especially during the formation of the fetal face, pregnant women are infected by viruses suffering from respiratory infections, rubella, etc., or taking certain chemical drugs such as hormones, may also affect the fetal facial deformities, cleft lip and palate; 4, bad habits: pre-pregnancy was addicted to tobacco and alcohol or during pregnancy often smoke, drink alcohol, nicotine, ethanol and other harmful substances in the body easily cause Fetal malformation, so that the chances of fetal cleft lip and palate increase.