Coagulation status and complications of pregnancy.

INTRODUCTION: There is much interest in the relationship between coagulation status and complications of pregnancy. The thrombelastograph (TEG) has been proposed as a useful, inexpensive tool to screen for patients with hypercoagulable states. MATERIALS AND METHODS: We investigated 588 unselected pregnant women at booking, obtaining blood samples for TEG and thrombophilia investigation. Pregnancy outcome data was recorded. RESULTS: We found significant correlations between TEG parameters and the Prothrombin time (PT) and Activated Partial Thromboplastin time (APTT) (p<0.01) and with plasma Antithrombin level (p<0.01). There was no correlation between TEG and other thrombophilic defects (protein C, protein S, Factor V Leiden mutation, Prothrombin G20210A mutation, MTHFR C677T mutation and Lupus Anticoagulant). There was a significant association of TEG parameters with mid-trimester loss (MTL) but not with other adverse pregnancy outcomes. CONCLUSIONS: The correlation between TEG and PT, APTT and antithrombin level supports its value in providing a global measure of haemostasis. Coagulation status at booking is associated with increased risk of MTL but not with complications occurring later in pregnancy.

The effects of folic acid supplements on coagulation status in pregnancy.

Thromboembolic disease remains the leading cause of maternal death in the UK. Recent literature has proposed that folate status is a strong predictor for venous thrombosis. Using thrombelastography (TEG((R))), we tested the hypothesis that folic acid supplementation is associated with a reduction in whole blood coagulability. Blood samples and questionnaire data were obtained at a mean gestation of 13.6 weeks (SD: 3.8, range: 6-38 weeks) from unselected consecutive women attending for their antenatal booking scan. Of 588 patients, 439 (74.7%) took folic acid. All TEG((R)) parameters were less hypercoagulable in women that had taken folic acid compared with those that had not: mean maximum amplitude (MA) 60.3 versus 62.1; mean difference 1.8; 95% confidence interval 0.8, 2.8; P = 0.0001; mean coagulation index (CI) 0.54 versus 0.85; mean difference 0.31; 95% confidence interval 0.11, 0.5; P = 0.002. There was no difference in the incidence of the homozygous MTHFR mutation in patients taking folic acid (5.53%) compared with those that were not (4.08%). This study suggests that benefit may be derived from longer-term treatment, although large multicentre studies are required to determine whether the relative hypocoagulability is associated with a reduction in risk of venous thrombosis.

Venous thromboembolism associated with the management of acute thrombotic thrombocytopenic purpura.

Venous thromboembolism (VTE) is not a feature of thrombotic thrombocytopenic purpura (TTP), but there has been a recent report of VTE in association with plasma exchange (PEX) treatment for TTP using the solvent detergent (SD) plasma, PLAS+SD. We reviewed the occurrence of VTE in 68 consecutive patients with TTP (25 men, 43 women). Eight documented VTE events [six deep venous thromboses (DVTs), three pulmonary emboli] were identified in seven patients (all female) during PEX therapy. All six DVTs were associated with central lines at the site of thrombosis. Other known precipitating factors included pregnancy, immobility, obesity and factor V Leiden heterozygosity. VTE occurred at a mean of 53 d following the first PEX. The European SD plasma, Octaplas was the last plasma to be used in PEX prior to the VTE in 7/8 events. This is the first report of VTE following Octaplas infusion. VTE is a multifactorial disease and, although several known precipitating factors were present in all patients in this study, the use of large volumes of SD plasma in PEX may be an additional risk factor. We recommend prevention of VTE with graduated elastic compression stockings (class I) at diagnosis and prophylactic low-molecular-weight heparin once the platelet count rises above 50 x 10(9)/l.