[Epidemiological survey of conjoined twins in China]

A descriptive study was conducted to investigate the incidence and epidemiological characteristics of conjoined twins in China. From 1988 to 1992, data were collected from more than 500 hospital-based units involved in a monitoring program and were analyzed by the National Center for Birth Defects Monitoring. The monitored subjects were the hospitalized births from 28 weeks gestation to a period within 7 days after delivery. 106 conjoined twins were found in 3,246,408 births with an incidence rate of 0.3/10,000. The highest rate was 0.8/10,000 in He'nan Province and Anhui Province(P < 0.05), and the lowest 0.1/10,000 in Beijing and Jilin Province (P < 0.01). Conjoined twins were more common in females; the ratio of female to male was 2 to 1. No difference was observed between the urban and rural areas. The prenatal mortality was as high as 915@1000. Only 31.13% conjoined twins were diagnosed prenatally. The results indicate that the incidence of conjoined twins in China is not different from that in other countries, but the work of prenatal diagnosis in China should be improved.