Understanding the distinction between cleft lip and cleft palate: a critical step for successful prenatal detection

Orofacial clefts (OCs) are among the most common congenital anomalies, however, prenatal detection of cleft palate without cleft lip (CP) remains low. CP is associated with a higher risk of associated structural anomalies, recurrence risk and genetic aberrations. There is opportunity to optimize prenatal diagnosis, counseling and diagnostic genetic testing for OCs.Improving prenatal diagnosis of CP requires understanding that embryologically, the secondary palate develops from the 6th to the 10th week and fuses with the primary palate by the 12th week. Multiple first, second and third trimester 2D ultrasonographic markers for OCs have been described including the maxillary gap, frontal space, maxilla-nasion-mandible angle, retronasal triangle, palatino-maxillary diameter, equal sign, nonvisualization or gap in the soft to hard palate interface and loss of the superimposed line. We discuss the technique, evidence and limitations of each.Prenatal detection of OC can be optimized by employing 2D sonographic markers. Prenatal detection of CP may be improved by recognizing its high association with retrognathia/micrognathia.