Cleft lip and palate

Last revised by Joshua Yap on 8 May 2023

Cleft lip and palate is one of the commonest neonatal facial anomalies. In ~80% of cases, the two features tend to occur together 6.

It is estimated to occur with an incidence of ~1 in 700-1000 live births 1. This can increase to 4% for a sibling of a previously affected fetus and up to 10% for a sibling of two previously affected infants 9

There is a recognized racial predilection. For example, the United States has one of the highest rates in terms of prevalence in Native Americans (~4 in 1000), followed by Asian (1.5-2 in 1000), White (1 in 1000), and Black (0.3 in 1000) populations.

Other associated anomalies can occur in up to 30-50% of cases 3,6. They are protean and include:

The lip forms between the 4th to 7th weeks of pregnancy. The roof of the mouth (palate) is formed between the 6th to 9th weeks of pregnancy. The condition results during the 4th to 6th weeks of gestation from a failure of fusion of one or both of the medial nasal prominences. These initially occur as paired medial nasal processes and failure of fusion with each other or with the maxillary processes will result in cleft lip with or without a cleft palate. Clefts in the anterior palate disrupt this normal line of fusion, resulting in the discontinuity in the smooth, C-shape contour of the alveolar ridge at the junction between the lateral incisors and canine tooth sockets, extending posteriorly to the incisive foramen. Much less commonly, the defect may occur between the medial and lateral incisors. 

In a bilateral cleft lip and palate, there is a premaxillary protrusion that is typically seen as a paranasal echogenic mass. The premaxillary protrusion results from instability of the facial structures during embryologic development, which produces uninhibited growth of the vomer and premaxillary bones and soft tissues. Although this occurs with a bilateral complete cleft lip and palate, it does not occur with other types of facial clefts or with cleft palate alone.

The majority are unilateral and 70% of these are on the left.

Several classification systems exist. The Nyberg 1995 antenatal ultrasound classification system is one that correlates very well with the severity of the defect with outcomes and is divided into five types 5:

An isolated cleft palate is almost impossible to diagnose in utero and is not part of this classification.

In a sizable proportion, it is sporadic, although various inheritance patterns have been described 10.

Sonographic features can be variable depending on the exact type of cleft anomaly. In general, an upper lip defect may be seen and is best appreciated on angled coronal scanning. A vertical hypoechoic region through the fetal upper lip usually represents the defect in the cleft lip. This finding may be corroborated by a similar defect of the soft tissues of the upper lip overlying the maxilla in the axial plane.

The palate can be examined in the transverse (axial) plane. 3D ultrasound may further assist in diagnosis. It is good practice to comment on fetal swallowing in real time as the ultrasound is performed.

Type-specific sonographic features include:

  • type III: may be seen as a premaxillary echogenic mass 8

  • there can be polyhydramnios if the defect is severe and impairs swallowing

The overall prognosis is variable depending on associated anomalies with isolated lateral clefts (types I and II) having the best prognosis.

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Cases and figures

  • Figure 1: incomplete cleft palate
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  • Case 1
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  • Case 2
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  • Case 3a
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  • Case 3b
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  • Case 4
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  • Case 5
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  • Case 6a: 2D ultrasound
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  • Case 6b: 3D ultrasound
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