PB1394 - Evaluating the haemostatic changes in pregnancy via global coagulation assays: A series of 27 pregnant females in the first trimester

Background: Pregnancy is a hypercoagulable state and is associated with thrombotic complications. However, traditional screening coagulation assays are not sensitive to detecting such haemostatic changes. Global coagulation assays such as clot waveform analysis (CWA) and thrombin generation assays (TGA) may be able to detect changes in the coagulation status of pregnant patients. While TGA changes have been studied in the pregnant population, aPTT-CWA has yet to be explored.

Aims: We aim to study the changes in aPTT-CWA and TG in females who are pregnant in their first trimester compared with a normal control population.

Methods: Plasma samples were collected from patients during the first trimester of pregnancy, defined as before 12 weeks of gestation. Standard coagulation assays were performed. aPTT-CWA parameters were generated using CS2100i coagulometer (Sysmex). TGA was performed using the Calibrated Automated Thrombogram (CAT). Results were compared to normal controls.

Results: 27 females in the first trimester of pregnancy were included in this study (Table 1). PT and aPTT parameters were within the normal reference ranges. D-Dimer was elevated with a mean of 0.59 mg/L, and Protein S was on the lower limit of normal with a mean of 57%. Compared with controls, aPTT-CWA parameters were significantly higher in pregnant patients, suggesting hypercoagulability (min1: 6.41%/s vs 4.69%/s, p <.001; min2: 1.01%/s2 vs 0.74%/s2, p <.001, max2: 0.85%/s2 vs 0.67%/s2, p <.001). This trend was also demonstrated in thrombin generation assay with CAT parameters of mean Estimated Thrombin Potential (ETP) and Peak Thrombin significantly higher (ETP: 2233.47 nM/min vs 1370.78 nM/min, p < .001, Peak Thrombin 388.05nM vs 274.58nM, p< .001). (Table 2)

Conclusion(s): Changes in haemostasis indicative of hypercoagulability happens early in pregnancy in the first trimester, and these changes are demonstrated via global coagulation assays. Such assays like the aPPT-CWA may serve as potential assays to monitor coagulation status in pregnancy.