Incidence of cleft lip, cleft palate, and cleft lip and palate among races: a review

A review of the literature pertaining to the incidence of cleft lip, cleft palate, and cleft lip and palate in different races is presented. The studies have been evaluated according to the method used to record the incidence rate. Half of the studies include in their base population livebirths, stillbirths, and abortions, or livebirths and stillbirths to record the incidence rate. In addition, in most of the studies, clefts with associated malformations and possible syndromes are included in the reported incidence. There is evidence, however, to suggest that the risk of developing clefts in stillbirths and abortions is three times as frequent as in livebirths and that clefts with associated malformations behave differently epidemiologically from clefts without associated malformations. It is suggested, therefore, that the incidence of cleft lip, cleft palate, and cleft lip and palate should be studied separately for each group, namely for livebirths, stillbirths, and abortions and should be reported separately for clefts without associated malformations, clefts with associated malformations, and syndromes. More research is needed to study the risk of developing clefts among the various groups that exhibit different epidemiologic behavior for each race.