抄録
In Shirakawa Agricultural area in Fukushima Prefecture, 1763 premature babies (babies with a birth weight of 2, 500 gm, and less) were born during the period 1948 to 1956.
The occurrence rate of Premature births was 6.2 percent (male 5.5, Femal 6.9) of the total numbers of a live births. The death rate of premature infants was 221.2, which was five times higher than the death rate of mature infants. The frequency of premature was the highest in the first born but the mortality was the lowest in the first-born.
The neonatal death rate of premature infants was ten times higher than that of mature infants.
The risk of death during infancy is strongly determinated by birth weight
