An epidemiological study of congenital reduction deformities of the limbs.

A retrospective study that was undertaken to determine why more infants had been born with congenital reduction deformities of the limbs is reported. The increase was detected by the Congenital Anomaly Surveillance System in 1969. Ninety-three infants born in Alberta and British Columbia in 1969-71 with congenital reduction deformities were matched with 93 normal infants and 93 infants with congenital malformations of a different type. The mothers of all infants were interviewed to obtain information on factors thought relevant to the establishment of a causal relationship. Although there were some significant differences between cases and normaland/or abnormal controls, this number of differences might have been expected by chance. No single causal relationship was established.