 Most prophylactic measures tested over the years have failed to prevent these adverse outcomes in twin pregnancies. Since administration of low-dose of aspirin can improve placental function and all these adverse outcomes in high-risk pregnancies, mainly in women with prior adverse outcomes, we suggest that similar benefits could be seen in twins. We are expecting that the administration of low-dose of aspirin starting in the first-trimester in twin pregnancies could lead to an improvement of placental function, a reduction or these adverse perinatal outcomes and therefore to an improvement of birthweight. 