Incidence of facial clefts in Cambridge, United Kingdom

The aim of this study was to determine the incidence of facial clefting in Cambridge, UK, using multiple resources of ascertainment and to relate the findings to antenatal ultrasound screening (AUS) detection rates. AUS records from an obstetric ultrasound department, post-natal records from the regional craniofacial unit, and autopsy reports of foetuses over 16 weeks' gestational age from a regional pathology department from 1993 to 1997 were retrospectively reviewed. Cross-referencing between the three data sets identified all cases of facial clefts. Of 23 577 live and stillbirths, 30 had facial clefts. AUS detected 17 of these. Sixteen of the 30 had isolated facial clefts. Others had associated anomalies, chromosomal defects, or syndromes. Percentages and confidence intervals were calculated from the above data. Twenty-one resulted in live births, seven terminations, and two foetal deaths. Overall, detection rate by AUS was 65 per cent [67 per cent isolated cleft lip, 93 per cent cleft lip and palate (CLP), and 22 per cent isolated cleft palate], with no false positives. The incidence of facial clefts was 0.127 per cent (95 per cent confidence interval 0.089-0.182 per cent); the incidence for isolated CLP was lower than previously reported: 0.067 per cent (0.042-0.110 per cent). With one exception, all terminations were in foetuses with multiple anomalies. The figures presented will enable joint CLP clinics to give parents information of termination rates. The study allows pre-pregnancy counselling of families previously affected by clefting about the reliability of AUS detection rates.