Cleft lip and cleft palate occur when tissues in the baby's face and mouth don't form properly. Normally, the tissues that make up the lip and palate fuse together in the second and third months of pregnancy. But in babies with cleft lip and cleft palate, the fusion never takes place or occurs only partially, leaving an opening (cleft).

Researchers believe that most cases of cleft lip and cleft palate are caused by an interaction of genetic and environmental factors. In many babies, a definite cause isn't discovered.

  • Genes inherited from the parents. Either the mother or the father can pass on genes that cause clefting, either as an isolated defect or as part of a syndrome that includes clefting as one of its signs. In some cases, babies inherit a gene that makes them more likely to develop a cleft, and then an environmental trigger actually causes the cleft to occur.
  • Exposure to certain substances during pregnancy. Cleft lip and cleft palate may be more likely to occur in pregnant women who smoke cigarettes, drink alcohol and take certain medications.
Jun. 14, 2012

You Are ... The Campaign for Mayo Clinic

Mayo Clinic is a not-for-profit organization. Make a difference today.