TY - JOUR T1 - First trimester employment, working conditions and preterm birth: a prospective population-based cohort study JF - Occupational and Environmental Medicine JO - Occup Environ Med SP - 654 LP - 660 DO - 10.1136/oemed-2020-107072 VL - 78 IS - 9 AU - Tanja Vrijkotte AU - Teus Brand AU - Gouke Bonsel Y1 - 2021/09/01 UR - http://oem.bmj.com/content/78/9/654.abstract N2 - Objectives To explore the association between working conditions during first trimester and total preterm birth (PTB), and subtypes: spontaneous PTB and iatrogenic PTB, additionally to explore the role of hypertension.Methods Pregnant women from the Amsterdam Born Children and their Development study, filled out a questionnaire between January 2003 and March 2004, two weeks after first prenatal screening (singleton liveborn, n=7561). Working conditions were working hours/week, standing/walking hours/week, physical work load and job strain.Results Prolonged standing/walking during first trimester was associated with an increased risk for total PTB (OR=1.5; 95% CI 1.0–2.3, after adjustments). Other working conditions were not related to total PTB. The separation into spontaneous and iatrogenic PTB revealed that standing/walking was associated with iatrogenic PTB only (OR=2.09; 95% CI 1.00–4.97). The highest risk was found for the combination of a long workweek with high physical work load (OR=3.42; 95% CI 1.04–8.21). Hypertension did not mediate these associations; however, stratified analysis revealed that high physical work load was only related to iatrogenic PTB when pregnancy-induced hypertension was present (OR=6.44; 95% CI 1.21–29.76).Conclusion This study provides evidence that high physically demanding work is associated with an increased risk for iatrogenic PTB and not with spontaneous PTB. Pregnancy-induced hypertension may play a role: when present, high physical work load leads to a more severe outcome.Data are available upon request due to ethical restrictions related to protecting patient confidentiality. Researchers who are interested in using data for research purposes can apply for access to the Amsterdam Born Children and their Development data by contacting the research committee at abcd@amc.uva.nl. ER -