Abstract
A few population studies on congenital malformations in Japan encouraged the auther to investigate the frequency of and the affecting factors on the occurence of congenital malformations in a birth cohort at the defined area, NAGOYA. The 41, 028 live born babies in 1965 were followed up for 4 years by linking birth and death certificates. The subjects analysed in this study are 96 deaths with congenital malformations of 644 deaths in the follow-up period and 42 malformed babies of 807 late stillbirths in 1965. Cardiovascular system accounts for a half of the malformations among the deaths and central nervous system for nearly two thirds among the stillbirths. Significantly high frequencies of malformations are observed among babies with the following characteristics ; 1) short gestational period (8 or 9 months) 2) low birth weight (less than 2,501 grams) 3) twin birth 4) high birth order (fourth or more) 5) old mother (35 years old or more) 6) long duration of parental wedlock (7 years or more) 7) working mother (sales-, service-women and farmers) 8) illegitimate birth Some of malformations interestingly showed the increasing or decreasing tendency of their frequencies with advancing parental age. These results suggest that the congenital malformations of multifactorial origin may be prevented by better family planning and some sort of modification of socio-economic factors.
