AbstractsA relationship between pregnancy outcome and working conditions for women has been reported frequently. In France, changes in such conditions, if indicated, are required by law. The present study shows how the outcome of pregnancy was related to working conditions in France in 1981, when a nationwide survey of births was carried out.The study was confined to 2387 employees who had worked during the first trimester of pregnancy and after. Two indicators of outcome of pregnancy were selected: preterm delivery occurring before 37 completed weeks of amenorrhea and birth weight below 2500 gm.Among employees who worked beyond the first trimester, 39 per cent belonged to the group of manual occupations: production workers (21 per cent), service workers (12 per cent), and shop assistants (6 per cent). The second group included professional workers (7 per cent), managerial workers and teachers (19 per cent), and clerical workers (35 per cent).Preterm delivery was significantly more frequent among production, shop, and service workers (7 per cent, as compared to 4 per cent among professional, administrative, or clerical staff; P < 0.01).Assembly line workers had preterm delivery more frequently than other women, this relationship being significant among manual workers only. All women who combined three or four of the strenuous working conditions (standing positions, heavy load carrying, assembly line work, and physically demanding work) had a significantly higher preterm delivery rate (8 per cent) than women who had none of these conditions (4 per cent) or one or two of them (5 per cent).For the four strenuous working conditions listed above, the proportion of women who did not work at all during the third trimester was higher when the work was strenuous. Reasons for the absences were varied, but apart from the legal prenatal leave, sick leaves were the most frequent. They were commoner and longer when the work was physically tiring.Women whose employers refused to modify their working conditions had a high rate of sick leave, and they were more likely to stop working after the second trimester than other women. The same trend was observed in the women who thought a modification of their working conditions impossible. Women who considered these changes unnecessary had shorter periods of sick leave. Women who benefitted from a change had a high rate of sick leave, although they were unlikely to stop working during the third trimester. These figures were the same, whatever the working conditions happened to be.