Cleft Lip and Cleft Palate in New South Wales

The complete birth statistics of 94 hospitals in New South Wales for the years 1964, 1965 and 1966 were examined to determine the incidence of cleft lip and/or cleft palate. The survey accounted for slightly more than half the births registered in this State during the study period. There was one live-born infant with a cleft defect among 821 births, or 1·21 per 1,000 live births, out of a total of 143,984 live births. Significant associations were found between the sex of the infants and the distribution of certain types of cleft, and such associations were thought to exist between the births of infants with a cleft defect and late maternal age and also with prematurity of the infant. No seasonal or geographical trends in the distribution of births of infants with a cleft defect were found in New South Wales, but this may not rule out such ætiological associations. Also, 20% of infants with a cleft defect were found to have one or more additional congenital defects. Retrospective epidemiological studies, such as this, present special problems.