TY - JOUR AU - Dahm, Anders E. A.; Jacobsen, Eva Marie; Wik, Hilde Skuterud; Jacobsen, Anne Flem; Mollnes, Tom Eirik; Kanse, Sandip M.; Sandset, Per Morten TI - Elevated Complement C3 and C4 Levels are Associated with Postnatal Pregnancy-Related Venous Thrombosis SN - 0340-6245 SN - 2567-689X PY - 2019 JO - Thromb Haemost JF - Thrombosis and Haemostasis LA - EN VL - 119 IS - 09 SP - 1481 EP - 1488 ET - 2019/06/29 DA - 2019/09/01 KW - venous thromboembolism KW - pregnancy KW - complement system proteins KW - blood coagulation KW - case–control studies AB - High levels of complement C3 are associated with venous thrombosis (VT) in the general population. We investigated if high C3 and C4 levels were associated with pregnancy-related VT. We undertook the Norwegian VIP study, a case–control study of VT in pregnancy or within 3 months postpartum (cases, n = 313) and women without pregnancy-related VT (controls, n = 353). Determinants of C3 and C4 in the control women were investigated with linear regression and the odds ratio (OR) for pregnancy-related VT was calculated with logistic regression. We found that levels of C3 and C4 were associated with body mass index (BMI), C-reactive protein (CRP); with the coagulation factors (F) fibrinogen, FVIII, and FIX; and with the coagulation inhibitors antithrombin, protein C, protein S, and tissue factor pathway inhibitor. These associations were influenced by CRP levels. The crude OR for pregnancy-related VT was 1.8 (95% confidence interval [CI], 1.1–3.0) for C3 above the 90th percentile and 2.0 (95% CI, 1.2–3.2) for C4 above the 90th percentile. Stratification in antenatal and postnatal VT showed that C3 and C4 were only associated with postnatal VT with an OR for high C3 of 3.0 (95% CI, 1.8–5.0), and for high C4 of 2.6 (95% CI, 1.5–4.6). Adjustment for high FIX and BMI reduced the ORs. We conclude that the association between postnatal VT and C3 and C4 suggests that there is clinically relevant crosstalk between the complement and the coagulation system. PB - Georg Thieme Verlag KG DO - 10.1055/s-0039-1692426 UR - http://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0039-1692426 ER -