What is it?
A cleft is a gap in either the upper lip, or the palate, or both. Clefts of the lip may vary from a notch in the lip to a complete split reaching up into the nose. They can occur on one side (unilateral) or both sides (bilateral).
The palate is made up of two parts – the hard (bony) palate at the front and the soft (muscular) palate at the back, ending with the uvula. Cleft palate can occur alone or in combination with cleft lip. It may be unilateral or (more rarely) midline when it is associated with higher rates of other birth defects.
Small clefts affecting only the soft palate are often not diagnosed at birth, especially if the overlying membranes remain intact (sub mucous clefts). These milder defects often present in the first years of life when associated speech problems become more apparent.
The face develops from several different areas that then fuse together. This occurs by about 5 weeks after conception for the lips and by about 9 weeks for the palate (the roof of the mouth). Clefts may develop if this process doesn’t work properly.
Causes and risk factors
In most cases the exact cause is unknown, but it is thought to be a combination of genetic and environmental factors. It is also seen in chromosomal disorders particularly Trisomy 13 and triploidy. Isolated cleft palate seems to have a different genetic origin to defects involving a cleft lip. Other risk factors include:
Family history of clefts suggesting a genetic link.
Low maternal intake of folic acid in early pregnancy.
Maternal smoking and increased alcohol intake.
Maternal obesity and poor nutrition.
Maternal medications including some anti epileptic drugs, methotrexate and isotretinoin.
Defects involving a cleft lip can be diagnosed on antenatal ultrasound at 20 weeks, although isolated cleft palate is much harder to detect. CARIS data shows that approximately 70% of cases are detected before birth.
Patterns and trends
1,650 cases in total have been reported to CARIS (1998-2021) for all forms of clefting, giving a gross rate of 20.3 per 10,000 total births.
Across Wales, rates of isolated cleft palate vary between local authority areas, with higher rates seen in north west Wales. This finding has been investigated in the past but no reason for the pattern has been identified. CARIS continues to keep the situation under review.
Wales compared to elsewhere
Many EUROCAT registers report similar rates of facial clefting to Wales. The overall live birth rate reported by EUROCAT is 14.7 per 10,000 births (1:680 live births).
Management and outcome
A multidisciplinary team will be involved from the diagnosis to aid with feeding, speech and repair of the defect.