Clinical Question

Is low-dose aspirin effective in decreasing the likelihood of preeclampsia?

Bottom Line

Low-dose aspirin—ranging from 60 to 100 mg per day—beginning as early as the second trimester decreases the risk of preeclampsia, preterm birth, and intrauterine growth retardation in women who are at high risk of preeclampsia. No harms to the mother or newborn were identified in the studies. (Level of Evidence = 1a)

Synopsis

To perform this systematic review, these authors searched four databases, including the Cochrane Central Register of Controlled Trials, to identify 15 English-language randomized controlled trials that evaluated the ability of low-dose aspirin to decrease the risk of preeclampsia, preterm birth, and intrauterine growth restriction. They also evaluated two additional observational studies to assess harms. Two investigators independently selected articles for inclusion, and two investigators evaluated study quality, which was generally high. The studies enrolled almost 12,000 patients, with two studies contributing 76% of the total. Low-dose aspirin reduced preeclampsia by 2 to 5 percentage points, depending on baseline risk. Intrauterine growth retardation was also reduced by 1 to 5 percentage points, as was preterm birth (2 to 4 percentage points). No harms were identified. There was no significant heterogeneity for these outcomes.

Study design: Systematic review

Funding source: Government

Setting: Outpatient (any)

Reference: HendersonJTWhitlockEPO'ConnorESengerCAThompsonJHRowlandMGLow-dose aspirin for prevention of morbidity and mortality from preeclampsia: a systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med.2014; 160( 10): 695– 703.