Thrombin generation assay identifies individual variability in responses to low molecular weight heparin in pregnancy: implications for anticoagulant monitoring.

Low molecular weight heparin (LMWH) given to inhibit coagulation and reduce the risk of thrombosis, is typically monitored by anti-Xa assay. However, anti-Xa levels may not necessarily provide an accurate measure of coagulation inhibition. Moreover, pregnancy is associated with hypercoagulability, which may compromise the efficacy of LMWH. We looked at the association between anti-Xa levels and parameters of thrombin generation assay [TGA; area under the curve (AUC), peak height (PH) and time to peak (ttP)] using samples from 41 pregnant women receiving LMWH and 40 normal pregnant women controls. TGA results confirmed the physiological hypercoagulability of normal pregnancy (mean normalised values: AUC 119%; PH 157%; ttP 72%). Although anti-Xa measures correlated with all three TGA parameters, this group correlation masked significant inter-individual variability, demonstrated by the R(2) value or coefficient of determination. Anti-Xa levels contributed to 74% of variation in AUC values, 63% of variation in PH values and only 53% of variation in ttP values. The remainder reflects the contribution of patients' intrinsic coagulation status. Hence, some patients with 'safe' anti-Xa levels may potentially be under-anticoagulated, particularly in pregnancy. Measuring coagulability directly with TGA may lower the risk of adverse events due to under-anticoagulation in selected patients.

Levonorgestrel-releasing intrauterine system for the management of heavy menstrual bleeding in women with inherited bleeding disorders: long-term follow-up.

BACKGROUND: There are currently limited data on the use of the levonorgestrel-releasing intrauterine system (LNG-IUS) for the management of heavy menstrual bleeding (HMB) in women with inherited bleeding disorders (IBDs) particularly on its long-term (>12 months) efficacy. STUDY DESIGN: This study involves a case series of women with IBDs who received the LNG-IUS as treatment for HMB. Menstrual blood loss before its insertion and at the time of follow-up was assessed by the pictorial blood-loss assessment chart (PBAC) and hemoglobin (Hb) concentrations. A questionnaire was used to evaluate quality of life (QOL) during menstruation before and after insertion of the LNG-IUS. RESULTS: Twenty-six women were included. The median duration of LNG-IUS use at follow-up was 33 months (range, 14-103). The median PBAC score decreased from 255 (range, 134-683) to 35 (range, 0-89) with LNG-IUS use. The median Hb concentrations (11.2 to 13.2 g/dL) and QOL scores (median, 26 to 52) improved significantly with LNG-IUS use (p<.01). CONCLUSION: The LNG-IUS appears to be an effective long-term treatment for HMB in women with IBDs.