Influence of rest during pregnancy on birth weight in working women

Birth weight in Sweden has increased during the past decades. We investigated whether rest provided by the combination of time off from work and social benefits among working pregnant women contributed to the observed changes.

A total of 7,459 consecutively delivered women in 1978, 1986, 1992, and 1997 at 2 delivery wards in southeastern Sweden were studied.

Between 1978 and 1997, the average birth weight among the children of the women studied increased from 3,484 to 3,566 grams (P < .001). The in-crease in weight was most evident among infants born to women who were employed during pregnancy. The use of social benefits and increased rest during pregnancy did not significantly influence birth weight (P = .107), even after adjustment for gestational length, parity, smoking, age, and occupation.

The continuous increase in infants' birth weight among pregnant women in this study did not correlate with rest periods in the form of leave supported by social benefit programs. The effects of social benefit programs on pregnancy outcome may thus be overrated and merits further research.