Pre-eclampsia is a major contributor to perinatal morbidity and mortality. Large studies of high-risk pregnant women have shown reduced risk of developing pre-eclampsia when they are treated with low-dose acetylsalicylic acid in early pregnancy. Treatment is also effective in preventing intrauterine growth restriction, preterm birth and perinatal death. No major side effects, including risk of malformations or miscarriage, are reported. It is important that general practitioners are aware of women who have an increased risk of developing pre-eclampsia, so that treatment with 100 mg of acetylsalicylic acid can be started early in pregnancy.