Cleft lip – palate – unilateral

Cleft lip – palate – unilateral


Discontinuity or clefting of the fetal lip involves the vermilion or cutaneous portion of the lip, and results from a partial or complete defect in fusion of the two lateral maxillary processes of the face with the central frontonasal process, early in embryonic life. The defect can be as subtle as a notch in the vermilion border or as obvious as a large V-shaped cleft which extends into the floor of the nose. Notable as the most common malformation of the fetal face, cleft lip, with or without cleft palate, is found in about 1 per 1000 live Caucasian births, with significant racial and geographic disparity noted and a 2:1 male predominance. Cleft lip and palate is twice as common as isolated cleft lip. Clefting of the lip may be unilateral or bilateral, with the majority (75-80%) occurring unilaterally on the left. Associated malformations are far more frequent in cleft lip and palate and cleft palate alone than in isolated cleft lip. In the latter cases, additional anomalies are found in less than 5%; the incidence is at least doubled in the former categories. In recent studies, 15 to 20% of all patients with cleft lip, with or without cleft palate, have been found to have a recognisable syndrome. In the remainder, the aetiology is multifactorial. Prenatal diagnosis may allow counseling and referral for plastic surgery with high levels of patient satisfaction reported. Isolated cleft palate is more common than isolated cleft lip. It is a separate entity pathogenetically, with different syndromal associations. Median cleft lip is also different aetiologically. Both will be considered in separate sections.


Diagnosis of facial clefting by transvaginal sonography has been accomplished as early as 14 weeks when development of the fetal facial contour is complete. Diagnosis of all types of fetal facial defects may be more challenging in the third trimester with descent and engagement of the fetal head in the pelvis. Visualization of the face in standard sagittal, paramedian and coronal views is invaluable in aiding diagnosis. In unilateral cleft lip, the paramedian or para-sagittal views will be most informative whereas the midline or sagittal facial in image will be normal. Pseudoprognathism or protrusion of the mandible relative to the maxilla, only in the area of the cleft, may be an ancillary feature on parasagittal view. Confirmation of subtle unilateral clefting may be sought by imaging the lip in coronal planes. Three dimensional imaging, especially prior to 24 weeks gestation, may be useful in the identification of subtle defects. Two-thirds of fetuses with cleft lip will also have cleft palate and careful scrutiny of the deeper planes in coronal section for distortion of the alveolar ridge, bony palate and nose may reveal the concurrent involvement of the palate. Ancillary signs which may be suggestive of cleft lip with cleft palate include polyhydramnios and/or an absent, small or transiently visualized stomach. These are likely caused by the egress of amniotic fluid from the oropharynx through the cleft into the nasopharynx and back into the amniotic sac. As with all facial defects, diagnosis of cleft lip, with or without cleft palate, should prompt detailed review of fetal anatomy for additional anomalies. Karyotypic analysis is generally advised only when other anomalies are detected in addition to unilateral clefting.

Differential Diagnosis

Bilateral cleft lip/palate could be missed if parasagittal view of both sides of the face is not obtained or imaging is difficult due to orientation/position of the fetal head. A midline cleft lip ( premaxillary agenesis) may sometimes be confused with unilateral cleft lip/palate. A hypoplastic midface and other midline anomalies such as holoprosencephaly, arhinia, hypotelorism, or cyclopia may accompany midline cleft. Amniotic bands or limb-body-wall complex anomalies may also present with bizarre or atypical facial clefts. Recognition of the amniotic bands or extrafacial anomalies such as abdominal wall defects, limb defects, renal agenesis, scoliosis and/or absent or short umbilical cords should lead to accurate diagnosis.

Sonographic Features

Unilateral interruption of the superficial tissues of the upper lip, which may extend to the level of the nostril; if cleft palate is found concurrently, deeper tissues including nose, alveolar ridge, and bony palate may also be distorted. 

Pseudoprognathism or relative protrusion of the mandible may be seen on parasagittal section in the plane of clefting

Polyhydramnios with absent, small or transiently visualized stomach may be an associated finding.

Associated Syndromes

  • Acrocallosal
  • Chromosomal anomaly
  • Craniofrontonasal dysplasia
  • Early amniotic band rupture sequence
  • Ectrodactyly-ectodermal dysplasia-clefting syndrome
  • Hay Wells syndrome
  • Holoprosencephaly sequence
  • Hypertelorism-hypospadias (Opitz G)
  • Meckel
  • Miller syndrome
  • Popliteal web syndrome
  • Rapp- Hodgkin ectodermal dysplasia syndrome
  • Roberts-SC phocomelia syndrome
  • Teratogen exposure
  • Van der Woude syndrome


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