- Recall the results of previous studies relating work-related activities to pregnancy outcomes.
- Describe the findings of the present study and to what degree they are influenced by possible confounding factors such as gestational age.
- Explain the mechanisms by which prolonged standing at work might influence pregnancy, and for whom preventive measures might be appropriate.
The purpose of this study was to investigate the association between infant birth weight and standing at work during pregnancy. A total of 1222 pregnant women employed in a large petrochemical corporation in Beijing, China, were enrolled in the study after receiving permission from the government to have a child. The subjects were followed up from that time through their entire pregnancy, for a total of up to 12 months. All subjects delivered at the company staff hospital between 1996 and 1998. Various work-related physical activities during pregnancy were assessed using a structured questionnaire, and generalized additive models (GAMs) were performed to examine their association with birth weight. Of the assessed activities, only standing was significantly associated with birth weight. After adjusting for potential confounders, maternal standing hours per day at work was found to be significantly associated with reduced birth weight (−17.7 g, P = 0.03).
From the Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts (Dr Ha, Dr Cho, Dr Chen, Dr Xu, Dr Christiani); the Department of Preventive Medicine, College of Medicine, Ewha Womans University, Ewha Women’s Medical Research Center, Seoul, Korea (Dr Ha, Dr Park); the Department of Epidemiology, Seoul National University School of Public Health, Seoul, Korea (Dr Cho); and the Center for Ecogenetics, Peking University Health Science Center, Beijing, China (Dr Chen, Dr Wang).
Address correspondence to: David C. Christiani, Harvard School of Public Health, Department of Environmental Health., 665 Huntington Ave, Boston MA 02115; email@example.com
The author has no commercial interest related to this article.