What is the role of aspirin in the prevention of preeclampsia?

Updated: Nov 29, 2018
  • Author: Kee-Hak Lim, MD; Chief Editor: Ronald M Ramus, MD  more...
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A systematic review of 14 trials using low-dose aspirin (60-150 mg/d) in women with risk factors for preeclampsia concluded that aspirin reduced the risk of preeclampsia and perinatal death, although it did not significantly affect birth weight or the risk of abruption. [78] Low-dose aspirin in unselected nulliparous women seems to reduce the incidence of preeclampsia only slightly. [79] For women with risk factors for preeclampsia, starting low-dose aspirin (commonly, 1 tablet of baby aspirin per day), beginning at 12-14 weeks' gestation, is reasonable. The safety of low-dose aspirin use in the second and third trimesters is well established. [78, 80]

A 2016 ACOG Practice Advisory upheld the recommendation for the possible use of low-dose aspirin (81 mg/day), introduced between 12 and 28 weeks of gestation, to prevent preeclampsia in women who are high-risk. The U.S. Preventive Services Task Force defined high-risk for preeclampsia as women with a history of preeclampsia, multifetal gestation, chronic hypertension, diabetes, renal disease, or an autoimmune disease. [81]

On the basis of limited evidence from a systematic review and meta-analysis, the addition of low–molecular weight heparin or unfractionated heparin to low-dose aspirin has the potential to reduce the prevalence of preeclampsia and birth of small-for-gestational-age neonates in women with a history of preeclampsia. [82]

A multicenter, double-blind, placebo-controlled trial by Rolnik et al that included 1620 women at high-risk for preterm preeclampsia reported that 1.6% of the patients in the low-dose aspirin group had preterm preeclampsia compared to 4.3% in the placebo group (odds ratio in the aspirin group, 0.38; 95% confidence interval, 0.20 to 0.74; P=0.004). [83]

A secondary analysis of data from the Aspirin for Evidence-Based Preeclampsia Prevention trial reported that in high risk of preeclampsia pregnancies, administration of aspirin reduces the length of stay in the neonatal intensive care unit by about 70%. [113]

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