[Congenital cleft lip and palate. Population frequency in Moscow]

A study was carried out in 7 Moscow maternity hospitals to determine the population incidence of the facial clefting from 1970 to 1976. Among 142,911 newborns, including stillborns, 190 were bound to have such malformations. After removal of 14 cases with recognized syndromes, the incidence of multifactorial anomalies was estimated to be 0,75 per 1000 for cleft lip (palate) and 0,48 per 1000 for isolated cleft palate. The combined estimate of both was 1,23 per 1000 total births. Sex ratio was 1,33 in CL(P) group and 0,64 in CP group. No correlation was found between maternal age, birth season and the clefting incidence. However, both CL(P) and CP incidence strongly increased with birth order. This fact awaits further testing, since it is not consistent with the data in literature.