Commentary

Good biological rationale exists to explain why low doses of antiplatelet drugs should reduce the likelihood of pre-eclampsia, preterm birth, and their perinatal consequences among women at risk for pre-eclampsia. Small, randomised, controlled trials seemed to confirm the hypothesis, but subsequent large trials did not.¹ The discrepancy between the earlier positive results and the later negative ones was attributed to publication bias. In this systematic review and meta-analysis done as part of the work of the Cochrane Collaboration,² Duley et al have found that antiplatelet drugs confer important and statistically significant benefits on mothers at risk for pre-eclampsia and on their infants, without any identified risks. The review is powerful because it includes studies that are methodologically strong and because the total number of women enrolled is very large (>30 000). The findings of a modest reduction in risk for pre-eclampsia, preterm birth, and death of the fetus or baby with antiplatelet treatment are important. Additional information will come from the pooling of data from the existing trials about the effects of higher doses of aspirin, treatment among higher risk women, and treatment at an earlier point in gestation.

Compelling evidence exists to recommend general and widespread use of low dose aspirin (<75 mg) beginning after 12 weeks of pregnancy for women at risk for pre-eclampsia. The women most likely to benefit are those with a history of pre-eclampsia, chronic hypertension, or such medical problems as diabetes or renal disorders. Women with more moderate risk factors, however, may also benefit (eg, first pregnancy, multiple pregnancy, family history of pre-eclampsia, teenaged mother, abnormal result on uterine artery Doppler scan or rollover test, or mild increase in blood pressure without proteinuria). These women should also be offered this effective treatment.