Recurrent pregnancy loss (RPL) is a common health problem affecting 1-5% of women at reproductive age. Evaluation of three different antithrombotic treatments in women with antecedent of RPL, comparing the results in negative and positive to thrombophilic screening pregnant women. We recruited 361 women with an antecedent of two or more pregnancy losses. From this group, 167 women became pregnant and considered for the study. The evaluated pregnant women were divided as negative/positive to thrombofilic screening: (a) 80 (48%) with negative thrombophilic screening, (b) 87 (52%) positive to thrombophilic screening. Pregnant women included in the study and considered negative or positive for thrombophilic screening, were randomized into three different therapy groups: (a) group 1: Acetil salicylic acid (ASA) 100 mg daily until third month of pregnancy, (b) group 2: low molecular-weight heparin (LMWH) - enoxaparine 40 mg daily until third month of pregnancy, (c) group 3: ASA 100 mg plus LMWH 40 mg daily until third month of pregnancy. In 80 negative to thrombophilic screening pregnant women, the comparison of efficacy of the three treatments, shows that all three treatment regimens were significantly effective comparing live births against fetal losses. In 87 positive to thrombophilic screening pregnant women, the comparison of efficacy for the three regimens, shows that the therapy with LMWH or LMWH plus ASA are significantly protective against fetal losses with respect to ASA, which showed a high number of fetal losses (11 live births, 18 fetal losses). We suggest that thromboprophylaxis is indicated in women with RPL independently from positiveness to thrombophilic markers.