MATERNAL WORKING-CONDITIONS AND LAW BIRTH -WEIGHT IN MEXICO-CITY

Objective. To study the association between maternal working condition s and low birth-weight in Mexico City. Material and methods. Interview s of 2 623 workers who gave birth in Mexico City hospitals during 1992 were analyzed. Information on the main biologic and social factors as sociated to low birth-weight was registered. Occupational stress was d etermined with the instrument designed by Karasek. Logistic regression models to evaluate the relationship between working conditions and lo w birth-weight were used, controlling by confounding variables. Result s. Low birth-weight was more frequent in workers with working periods of more than 50 h/week (OR= 1.6; 95% Cl= 1.17, 2.28) and with problems at work (OR= 1.5; 95% Cl= 1.0, 2.25). Lack of tangible social support was identified as a risk factor for low birth-weight (OR= 1.7; 95% Cl = 1.20, 2.33). Preventive working measures such as changes in tasks, s hortening of working hours and leaves of absence due to illness did no t show a beneficial effects on birth-weight, except for the maternity leave of absence, Mothers with no right to this had a 2.2 higher proba bility of giving birth to low weight children (95% Cl= 1.66, 2.93). Co nclusions. These results emphasize the importance of identifying the o ccupational risk factors during pregnancy.