Perinatal study in Tientsin: 1978.

Clinical records of a total of 3320 singleton births, representing the year 1978, at the two Tientsin Medical College Hospitals, Tientsin, People's Republic of China, were studied to ascertain (a) reproductive parameters such as the average age of the mothers at first and successive births and (b) the relationships between perinatal deaths, prematurity and birth weight and the mothers's age, number of previous pregnancies, parity, maternal conditions in the prenatal and delivery period and operative procedures of delivery.