Objective: Describe and quantify stromal and trophoblastic lesions in placental villi of pregnant with antiphospholipid syndrome in antithrombotic therapy. Materials and Methods: cross-sectional descriptive study in which two placentas of pregnant women at term associated with antiphospholipid syndrome in therapy combined were analyzed. To control a placenta at term of healthy pregnant women was analyzed. Central and peripheral regions of each placenta were processed with hematoxylin-eosin, evaluating at the optical microscope 5 quantitative variables which were analyzed by ANOVA and Tukey test. Results: placental maturity was observed. Significant differences (p < 0.05) were found between the control and pathological placenta in relation to the deposition of fibrinoid material, edema, fibrosis and syncytial nodules, showing a higher proportion of placenta villi affected in the placenta associated with antiphospholipid syndrome. In conclusion: Placentas of pregnant women with antiphospholipid syndrome treated show a higher percentage of villous stromal and trofoblastic lesions, being the edema one of the most significant. Finally we infer that antithrombotic therapy had beneficial effect in these patients achieving successful completion of pregnancy.