Aspirin modestly reduces the risk of preeclampsia, premature delivery, and serious adverse pregnancy outcomes in at-risk women, according to a meta-analysis published online May 17 in the Lancet.

Lisa M. Askie, PhD, from the University of Sydney in Australia, and colleagues performed a meta-analysis of 31 randomized clinical trials of antiplatelet agents to prevent preeclampsia. The trials involved 32,217 women and 32,819 infants, and 98% of women were in trials of 50 to 150 mg of aspirin alone per day.

The researchers found that women receiving antiplatelet agents had a reduced risk of preeclampsia (RR, 0.90), a reduced risk of delivering before 34 weeks (RR, 0.90), and a reduced risk of having a serious adverse outcome (RR, 0.90). Antiplatelet agents did not significantly affect the risk of death in fetus or infant, having a small-for-gestational-age infant, or bleeding in the women or their infants.

“There are certain settings in which preeclamp-sia is almost a certainty, including women with preeclampsia in more than one pregnancy or women with chronic hypertension and preeclampsia in a previous pregnancy,” James M. Roberts, MD, and Janet M. Catov, PhD, of the University of Pittsburgh, write in an accompanying editorial. “In these settings, aspirin is justified.”

Askie LM, Duley L, Henderson-Smart DJ, et al. Antiplatelet agents for prevention of pre-eclampsia: a meta-analysis of individual patient data. Lancet. 2007;369:1791-1798.

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