In 2014, on the basis of findings from meta-analyses, the USPSTF began to recommend low-dose aspirin (81 mg/day) after 12 weeks of gestation to prevent morbidity and mortality from pre-eclampsia in women with a history of pre-eclampsia, multifetal gestation, chronic hypertension, type 1 or 2 diabetes, renal disease, or autoimmune disease. The American Congress of Obstetricians and Gynecologists followed with a similar recommendation last year. The level B evidence was based primarily on a meta-analysis showing a 24% reduction in the risk for pre-eclampsia.