Causes of cleft lip and palate 

A cleft lip or palate happens when the structures that form the upper lip or palate fail to fuse together properly when a baby is developing in the womb.

In most cases the exact cause is unknown, but it's thought to be a combination of genetic (internal) and environmental (external) factors.

Inherited genes

Research indicates that the genes a child inherits from their parents occasionally makes them more vulnerable to developing a cleft lip or palate. A number of genes have been identified that may be responsible.

In some cases there is a family history of clefts, although most children of parents with clefts will not develop them.

Environmental risk factors

A number of things have been identified that may increase a child's chance of being born with a cleft lip or palate. These are outlined below.

Lack of folic acid during pregnancy

All pregnant women are advised to take a daily supplement of folic acid during the first four months of pregnancy. Folic acid helps reduce the possibility of birth defects.

While it is known that folic acid deficiency during pregnancy increases the risk of a cleft developing, there is no firm evidence yet to suggest an intake of higher doses of folic acid prevents clefts. However, mothers from families with a history of clefting are often advised to take higher doses of folic acid during pregnancy. This should be discussed with your doctor.


A mother who smokes during pregnancy increases her baby's chance of being born with a cleft. The risks from passive smoking are not fully known, but it is a good idea to avoid breathing in high levels of secondhand smoke.

Read more about treatments to help you stop smoking.

Alcohol consumption

Some studies have shown a link between a mother's alcohol consumption during pregnancy and the development of a cleft lip or palate in her baby.

Read more about alcohol in pregnancy.

Obesity and nutrition

Mothers who are obese have a higher chance of their child being born with a cleft. Poor nutrition during pregnancy can also increase the risk.

Medications during pregnancy

It has been suggested that some medications taken during pregnancy may increase the risk of cleft lip and palate. These include:

Speak to your GP or midwife if you are concerned about any medication you are taking during your pregnancy.

Pierre Robin syndrome

Pierre Robin syndrome is a rare condition where a baby is born with a small lower jaw and a tongue positioned further back in the mouth than usual. This can result in breathing difficulties which requires careful positioning of the baby and, sometimes, a breathing tube placed through the nose.

Most infants with Pierre Robin syndrome will also have a cleft palate.

The cleft can usually be repaired with surgery, although treatment may be delayed if there are continuing issues with airway obstruction. The lower jaw usually has some 'catch-up' growth later and orthodontic treatment can further help the bite.

Page last reviewed: 21/07/2014

Next review due: 21/07/2016