Increasing Incidence of Clefts in Finland: Reliability of Hospital Records and Central Register of Congenital Malformations

Abstract

The treatment of cleft lip and/or palate [CL(P), CP] in Finland has been centralized to one unit since 1947. Since 1963 all congenital malformations are reported to a central register. Comparison of these two materials showed that altogether 3928 children with clefts, born from 1948 to 1975, were registered in a total of 2258850 live born children in Finland, corresponding an incidence of 1.74‰. There was a constant registered rise in the incidence from 1.34‰ in 1948–52 to 2.16‰ in 1969–75, indicating a corrected “true” increase in the incidence by 33% in 28 years, or approximately by over one percent per year. Of all registered clefts born 1963–75 23.5% were lacking from the Register of Congenital Malformations, and 10.3% from the hospital records. In 1948–75 55.8% of the clefts belonged to the group CP and 44.2% to CL(P). The incidence of CP increased from 0.78‰ in 1948–52 to 1.21‰ in 1969–75, and that of CL(P) from 0.53 to 0.95‰. An average of 13,8% of the CP-cases were submucous clefts. Their registered incidence in all live born children increased from 0.08‰ in 1948–52 to 0.19‰ in 1969–75.