Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 49 9 2020 08 24 1727 1733 . NAWSHERWAN Department of Preventive Medicine, School of Health Sciences, Wuhan University, Wuhan, Hubei, China Sumaira MUBARIK Department of Epidemiology and Biostatistics, School of Health Sciences, Wuhan University, Wuhan, Hubei, China Ghulam NABI Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang, China Suqing WANG Department of Preventive Medicine, School of Health Sciences, Wuhan University, Wuhan, Hubei, China Cuifang FAN Department of Obstetrics and Gynecology, Renmin Hospital, Wuhan University, Wuhan, Hubei, China 2020 06 23 2020 07 11 Background: Advanced maternal age (AMA) is considered a risk factor associated with preeclampsia and adverse pregnancy outcomes. We aimed to assess the mediating role of preeclampsia between AMA and adverse pregnancy outcomes. Methods: A sample of 14646 pregnant women from the tertiary hospital of Hubei Province, China, during the years 2011-2017 were included in this study. Pregnant women were divided into 4 groups according to their age at delivery. Mediated effect of preeclampsia with relation to AMA and adverse pregnancy outcomes was measured using structural equation modeling. Results: Women in the highest age group were significantly associated with preterm delivery [RR 1.37 (95% CI 1.24 - 1.49)] and low birth weight [RR 1.28 (95% CI 1.11 - 1.45)] compared with women in the lowest age group. The indirect effect (mediated effect) of AMA on preterm delivery and low birth weight mediated by preeclampsia was [β 0.053 (95% CI: 0.047, 0.060)], and [β 0.045 (95% CI: 0.038, 0.052)], respectively. The estimated mediation proportion of the effect of AMA due to mediated effect of preeclampsia was (35.5%) for preterm delivery and (23.5%) for low birth weight. Conclusion: Preeclampsia partially mediates the association between AMA and adverse pregnancy outcomes. https://ijph.tums.ac.ir/index.php/ijph/article/view/21220 https://ijph.tums.ac.ir/index.php/ijph/article/download/21220/6981