Associations of thrombocytopenia, transaminase elevations, and transfusion with laboratory coagulation tests in women with preeclampsia: a cross-sectional study

Background: Women with preeclampsia may develop coagulopathy, predisposing to bleeding complications. Although guidelines and prior studies conflict, we hypothesized that in preeclampsia, abnormal coagulation test results are more common in women with thrombocytopenia or transaminase elevations and increase the transfusion risk. Our objectives were to investigate: 1. patterns of coagulation testing; 2. relationships between platelet count, transaminase level, and the risk of abnormal coagulation tests; 3. risk of bleeding complications; and 4. characteristics of patients with markedly abnormal coagulation parameters.

Methods: We conducted a cross-sectional study of deliveries of women with preeclampsia who had undergone activated partial thromboplastin time (aPTT) or international normalized ratio (INR) testing at one of two hospitals between 1994 and 2018.

Results: Of 10 699 women with preeclampsia, 3359 (32.7%) had coagulation testing performed and aPTT or INR elevations were present in 124 (3.7 %). Coagulation abnormalities were more common in women with thrombocytopenia or transaminase elevations (n=82) compared with those without (n=42) (6.7%, 95% CI 5.5 to 8.2 vs 1.8%, 95% CI 1.3 to 2.5). Transfusion was more common among women with abnormal coagulation parameters (n=124) compared with those without (n=39) (33.1 vs 7.0%, P <0.001). Among 26 patients with an aPTT ≥40 s or an INR ≥1.4, six required transfusion (all had placental abruption and disseminated intravascular coagulopathy).

Conclusions: Coagulation testing was inconsistently performed in this cohort. Platelet counts and transaminase levels inadequately detected abnormal coagulation test results. Abnormal coagulation test results were associated with a markedly higher risk for red blood cell transfusion.