Cleft lip, with or without cleft palate, affects approximately one in every 1,000 newborn infants. It is a craniofacial, oral, and dental birth defect in which there is an opening in a structure around the mouth and face. The causes of this problem are both environmental and genetic. Twenty percent of these deformities are due strictly to genetic causes. The upper gums may be involved.
Clefts can occur on one or both sides, and with or without involvement of the palate.
Oral-facial clefts occur during the fourth to tenth week of fetal development. In 1982, Dr. Maria Tolarova discovered that preconceptual supplementation with a very high dose of folic acid reduced the recurrence rate of isolated cleft lip, with or without cleft palate, in Hungarian newborn infants. Since then, the use of folic acid supplements has become a standard part of prenatal care. Folic acid dramatically reduces the risk of giving birth to a baby with neural tube defects, such as spina bifida or anencephaly. Folic acid works by preventing damage to cellular DNA during cell division, and is essential for the normal growth of an embryo.