Effect of low-molecular-weight heparins on anti-Xa peak levels and adverse reactions in Chinese patients with recurrent spontaneous abortion: a single-center, observational study

OBJECTIVE: To compare three commonly used low-molecular-weight heparins (LWMHs) in the treatment of recurrent spontaneous abortion (RSA) by evaluating the anti-Xa peak levels and adverse reactions. METHODS: In this single-center, observational study, we enrolled 310 patients with RSA in whom anti-Xa levels were measured during pregnancy. Patients were divided into three groups according to the LMWH they used: the nadroparin group, enoxaparin group and dalteparin group. We compared the peak anti-Xa levels and the coagulation status of each group, and analyzed the incidence of adverse reactions, including local allergy, liver and renal dysfunction, and the impact on platelet. RESULTS: Patients in the enoxaparin group had a higher anti-Xa peak level than those in the nadroparin group (0.80 ± 0.22 IU/ml vs. 0.61 ± 0.24 IU/ml; P < 0.0001), although most patients in the three groups reached the target concentration of anti-Xa. Furthermore, patients in the enoxaparin group had a more stable anti-Xa levels during pregnancy. In addition, patients in the nadroparin group had a higher rate of local allergy than those in the enoxaparin group (60.5% vs. 42.5%; P = 0.004) and those in the dalteparin group (60.5% vs. 33.3%; P = 0.002). Further examination by the type of local allergy indicated a dramatic difference in pruritus and induration between the nadroparin group and the other two groups. No difference was found in the incidence of liver and renal dysfunction and thrombocytopenia. CONCLUSION: Compared with nadroparin and daltepatin, enoxaparin showed a better performance regarding anti-Xa levels and the incidence of adverse reactions in the treatment of RSA.