127-POS

Abstract

Objectives To assess the association between number of births and long-term maternal total and cardiovascular mortality stratified on education. Methods A population-based cohort study. Setting: Medical Birth Registry of Norway. Participants: Mothers with births registered in the Medical Birth Registry of Norway during the period 1967–2009. Mothers with first birth before 1991 were included. The data was organized in maternally linked sibling files. Cox proportional hazard models were used. Main Outcome Measures: Hazard ratios of maternal total and cardiovascular mortality, at 40–69 years, by number of births stratified on education (ten or less years and more than ten years of education). Results We found a J-shaped association between total mortality and cardiovascular mortality with increasing number of births among women with ten or less years of education, while there was no significant association among women with more than ten years of education. Compared to mothers with more than ten years of education and two births, the adjusted hazard ratio of cardiovascular death among those with five or more births and same education was 1.12 (95% confidence intervals (CI) 0.74–1.69). The corresponding hazard ratio among those with ten or less years of education was 3.57 (3.05–4.19). Mothers with only one birth had increased risk of both cardiovascular and total mortality, independent of educational level. Conclusions Our results suggest that the association between increasing number of births and later life cardiovascular mortality is explained by factors associated with educational level and not by adverse physiological changes accumulating over repeated pregnancies. The increased mortality among mothers with only one birth point toward underlying physiological factors associated with subfertility and/or chronic disease. Disclosures F. Halland: None. L. deRoo: None. N. Morken: None. K. Klungsoyr: None. A.J. Wilcox: None. R. Skjaerven: None.