作为母婴保健水平指标之一的乳儿死亡率在日本逐年降低,已成为世界上最低率国家之一。日本已成为人口动态方面少生少死型国家。乳儿死亡原因中的肺炎、支气管炎、急性胃肠炎等感染性疾病所占比例日渐降低,先天异常疾病所占比例相对年年增高。先天异常在乳儿死亡原因中所占比例于1979年占25.7%,占据首位。日本从1977年开始对苯丙酮尿症等五种先天性代谢异常疾病,进行普查筛检。从 The infant mortality rate, one of the indicators of the level of maternal and infant health care, has been decreasing year by year in Japan and has become one of the lowest-rate countries in the world. Japan has become a country of less developed and less vital population dynamics. In the causes of infant death, the proportion of infectious diseases such as pneumonia, bronchitis and acute gastroenteritis gradually decreased, while the proportion of congenital abnormalities increased year by year. Congenital anomalies accounted for 25.7% of the causes of infant death in 1979, occupy the first place. Japan from 1977 on phenylketonuria and other five congenital metabolic disorders, screening screening. From