The incidence of congenital malformations in a Chinese population: The Taipei collaborative study

Data are presented from an epidemiological survey of congenital malformations in 25,814 consecutive single and multiple births occurring in six hospitals in Taipei, Taiwan. All malformed babies were examined by at least one of four study physicians. The malformation rate was 13.23/1000 total single births, and ranged from 8.66 to 20.27/1000 births in the six hospitals. There also was significant interhospital variation in fetal death rate early neonatal death rate, and rate of multiple births. No significantly greater incidence of malformations in twins than nontwins was noted. Compared to other populations there were intermediate rates of anencephaly (1.17/1000 births), low rates of spina bifida (0.16/1000) and hydrocephalus (0.35/1000), and high rates of cleft lip with or without cleft palate (1.92/1000), radial polydactyly (1.02/1000), osteogenesis imperfecta (0.16/1000), and conjoined twins (1 in 6454 births). Methodological problems of incidence studies of congenital malformations are discussed.