Congenital cleft lip is caused by a number of factors that affect the fetus during its development. In particular, during the first 12 weeks of fetal development and molding, various different corresponding malformations occur due to the effects, and cleft lip is one of the more common ones. There are many factors that contribute to the occurrence of cleft lip, including genetics, nutrition, infection, injury or the effects of medication. The exact cause is not very clear and may be the result of one or more of these factors acting at the same time, so it is very important to take proactive preventive measures early in pregnancy. It is very important to prevent the occurrence of cleft lip. Mothers-to-be who are preparing for pregnancy should be educated about the subject and should pay attention to the proper distribution of nutrition. During pregnancy, it is important to avoid excessive stress and emotional excitement and to keep a happy mood. Do not smoke or drink alcohol, and try to avoid viral infections. In case of illness, drugs that may cause malformation of the fetus should be prohibited.