Sensitivity and accuracy of routine antenatal ultrasound screening for isolated facial clefts.

Facial clefts, as a group, represent one of the most frequently occurring congenital abnormalities detectable on prenatal mid-trimester scan. It has been estimated that, at term, approximately 1 in 1000 infants will be diagnosed with an isolated facial cleft. The aim of this study was to determine the sensitivity and accuracy of routine second trimester ultrasound screening for facial clefts. This was a prospective study of isolated fetal facial clefts, detected at 18-23 weeks gestation, in a routine obstetric population. The antenatal detection rate of facial clefts was derived by comparing the number of cases identified antenatally with the number of neonatal cleft surgeries performed in this centre, for the local population only. The accuracy of antenatal diagnosis of facial clefts was calculated by matching data from the ultrasound database to birth registries and neonatal cleft surgeries performed in this centre, including the referred cases. During the study period, 17,551 women underwent a routine anomaly scan at 18-23 weeks of gestation. A total of 30 babies underwent surgery for isolated facial cleft in this centre during that period. There were no false positive diagnoses of facial clefts, and in five cases (all unilateral), the antenatal diagnosis was found to be inaccurate. 12 babies were from the local population, of which 9 had an antenatal diagnosis of facial cleft, giving a sensitivity of 75%. The current study highlights the effectiveness of antenatal screening for facial clefts. Additionally, it highlights the appropriate terminology that needs to be used in the accurate description of antenatally diagnosed facial clefts.