Is the risk of cardiovascular disease in women with pre-eclampsia modified by very low or very high offspring birth weight? A nationwide cohort study in Norway

Objectives To examine whether the risk of cardiovascular disease (CVD) in women with pre-eclampsia is modified by very low or very high offspring birth weight. Further, we studied whether diabetes in pregnancy modified this risk. Design Nationwide cohort study. Setting Norwegian population registries. Participants 618 644 women who gave birth to their first child during 1980-2009. Methods The women were followed from delivery until the development of CVD or censoring, by linkage of the Medical Birth Registry of Norway to the Cardiovascular Disease in Norway project, and the Norwegian Cause of Death Registry. Primary outcome measure: CVD. Results Compared with normotensive women with normal offspring birth weight, women with pre-eclampsia had increased risk of CVD (HR 2.16; 95% CI 2.05 to 2.26). The CVD risk was even higher when pre-eclampsia was accompanied with a large for gestational age offspring (LGA, z-score >2.0) (HR 2.57; 95% CI 2.08 to 3.18). Women with pre-eclampsia and a small for gestational age offspring (SGA, z-score <-2.0) had an HR of 1.54 (95% CI 1.23 to 1.93) compared with normotensive women with normal offspring birth weight. Also, women with diabetes had increased CVD risk, but no additional risk associated with an LGA or SGA offspring. Conclusions Women with pre-eclampsia and an LGA offspring had higher risk of CVD than pre-eclamptic women with a normal weight (z-score -2.0 to 2.0) or SGA offspring. These findings suggest that factors causing pre-eclampsia and an LGA offspring are also linked to development of CVD.