Abstract
For over ten years now, the incidence of low-birth-weight infants has been on the increase in Japan. In this connection, it is believed that while intensive maternal and child health guidance and improvement of perinatal medical care have led to a decrease in spontaneous or perinatal fetal death, the incidence of low-birth-weight infants is increasing. However, there was a time lag of over ten years between the observertion of decreare in the stillbirth rate and increare in the incidence of low-birthweight infants. Furthermore, the increase in number of low-birth-weight infants in recent years has far exceeded the decrease in the number of stillbirths. Advanced age at childbirth is thought to be one of the causes of the increase in number of low-birth-weight infants, however, the incidence of low-birth-weight infants born of young mothers has also increased in recent years. Thus, the increased incidence of low-birth-weight infants can not be explained by the above-mentioned cause alone.
