[Effects of social and medical changes on the results of pregnancy between 1963 and 1972. I. General: maternal age, number of pregnancies, birth-weight, prematurity, still-birth, mothers foreign workers (author's transl)].

An analysis of 16,486 births in a city university obstetric department over 10 years showed: 1) The number of births in Austrians (A) declined by 30%, the number of guest worker's births (G) rose sharply from 1969 onwards and reached almost 20% of births in 1972. 2) The percentage of very young (under 21) A. mothers has not increased during the period, among G. mothers a younger age predominates but that will have to be related to the greater willingness of younger foreign women to emigrate. 3) In the last 10 years there have been more primiparous A. women and less with more than 4 children. Families became smaller. 77% A. mothers are between 16 and 30 years of age. G. mothers more often have their first or second child--related to selective emigration. 4) The accumulation of premature births in a University department apart, very young and relatively old A. mothers had much increased numbers of premature--defined by birth weight--children. G. mothers have not more children weighing less than 2501 g, but definitely more with low birthweight (2501-2750 g). 5) More than one third of A. children weighing less than 2501 g. are not premature according to time and among the children between 2501 and 3000 g. there also must be many prenatal dystrophics. 6) Still-births decrease in the lowest weights (less than 2501) the longer the pregnancy and rise steeply only after delay of birth by more than 2 weeks. It is lowest in slightly delayed births. With rising birthweights minimal stillbirths shift towards moderately early births. 7) Still-births are least common in heavy children of young mothers. 8) Premature births have not declined in A. mothers during the decade, premature stillbirth in A. mothers declined sharply since 1969. For G. mothers both prematurity and premature still-births have remained the same from 1969 to 1972.