 It will conduct a clinical trial, double-blind, randomized and placebo control group female patients with 12 weeks of gestation have one or more risk factors for developing preeclampsia. 2 groups will be formed with 82 patients each, chance will determine the intervention acetylsalicylic L-arginine acetylsalicylic acid or acid placebo. At the beginning and end of the intervention clinical and laboratory determinations, the end will be determined in both groups the incidence of preeclampsia, severity and number needed to treat is made. The data obtained were analyzed using SPSS statistical software version 22. It was considered statistically significant at p 0.05. 