[Relation between maternal age and neonatal physical development].

24,150 newborn infants and their mothers from 15 cities were investigated by analysing maternal age, neonate birth weight, length, head circumference, chest circumference, crown-hip length and arm circumference so as to find out scientific evidences for encouraging women to be pregnant at a mature age and improving birth quality. The women aged 20 or younger showed that the physical development indexes of their babies were lower as compared with the women aged 21 or older, and the percentage of mature infant was lowest as compared with the other age groups. In contrast, women aged 24-34, the neonatal physical development indexes were the best and percentage of premature and postmature infants were the lowest, especially in the 24-29 age group.