OBJECTIVES There is a major problem in providing prophylactic treatment in antithrombin (AT)-deficient pregnant women with a homozygous mutation of the heparin binding site (HBS) and AT level of 17 %. The aim of the study was to determine the effectiveness of heparin by monitoring changes in thrombin generation (TG) in vitro so that pregnant women are not exposed to stress in vivo. METHODS We used the chromogenic method for determination of factor Xa (FXa) inhibition for enoxaparine, nadroparine, dalteparine, fondaparinux and unfractionated heparin (UFH) and the Thrombin Generation Assay (TGA). RESULTS We found that the degree of inhibition is very different when different heparins are compared. Nadroparin reduces TG the most compared to low molecular weight heparins (LMWH). CONCLUSION Routine monitoring of anti FXa activity should be supplemented with TG monitoring, where the effect of LMWH does not manifest itself as this could help in estimating thrombophilic risk during pregnancy.

中文翻译：

---

纯合 II 型肝素结合位点抗凝血酶缺陷孕妇服用肝素后凝血酶生成减少。

目的 为肝素结合位点 (HBS) 纯合突变且 AT 水平为 17% 的抗凝血酶 (AT) 缺乏孕妇提供预防性治疗存在一个主要问题。该研究的目的是通过监测体外凝血酶生成（TG）的变化来确定肝素的有效性，从而使孕妇在体内不会受到压力。方法 我们使用显色法测定依诺肝素、那屈肝素、达肝素、磺达肝素和普通肝素 (UFH) 的 Xa 因子 (FXa) 抑制作用以及凝血酶生成测定 (TGA)。结果我们发现不同肝素比较时，抑制程度有很大差异。与低分子量肝素 (LMWH) 相比，那屈肝素可最大程度地降低 TG。结论 抗 FXa 活性的常规监测应辅以 TG 监测，其中 LMWH 的作用并不明显，因为这可能有助于估计妊娠期间的血栓形成风险。