Can an Aspirin a Day Lower Risk for Pregnancy Loss?

Summary and Comment |
February 23, 2017

Can an Aspirin a Day Lower Risk for Pregnancy Loss?

  1. Robert W. Rebar, MD

Low-dose aspirin increased live-birth rates in some women with prior pregnancy loss and high levels of high-specificity C-reactive protein.

  1. Robert W. Rebar, MD

Chronic inflammation has been implicated as a cause of pregnancy loss. High-specificity C-reactive protein (hsCRP), a marker of chronic inflammation, is commonly moderately elevated in individuals at excess risk for cardiovascular mortality. Daily low-dose aspirin (LDA; 81 mg) can safely lower this risk; moreover, LDA is recommended to prevent preeclampsia (Ann Intern Med 2014; 161:819). Investigators conducted a randomized trial in which LDA or placebo was administered to 1228 women (age range, 18–40) who were attempting to conceive after 1 or 2 prior pregnancy losses. Participants received study pills for six menstrual cycles or until gestational week 36. To determine whether any benefit of LDA on pregnancy and live-birth rates was affected by degree of preconception inflammation, analysis was stratified by baseline hsCRP levels.

Overall rates of pregnancy and live birth were 67% and 55%, respectively. For women in the lowest and middle hsCRP tertiles, pregnancy and live-birth rates did not differ between treatment groups. Among those in the highest tertile (hsCRP ≥1.95 mg/L), compared with placebo, LDA was associated with a 31% increase in clinically confirmed pregnancies (54% vs. 71%) and a 35% increase in live births (44% vs. 59%; P≤0.01 for both comparisons).


These data persuade me to discuss the possibility of trying daily low-dose aspirin for certain women with previous pregnancy losses. The risks associated with LDA are relatively low and the potential benefits high. However, LDA probably should be offered only to women with moderately elevated hsCRP — and not to all who have experienced pregnancy loss.

Note to readers: At the time NEJM Journal Watch reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.

Editor Disclosures at Time of Publication

  • Disclosures for Robert W. Rebar, MD at time of publication Grant / Research support Religious, Ethical and Cultural Impacts on the Delivery of Reproductive Healthcare: A Program for InterProfessional Education (RECIPE; Co-Principal Investigator) from the Association of Professors of Gynecology (APGO) Education Foundation Editorial boards Contraception (Deputy Editor); EndoText (Section Editor); Clinical OB/GYN Alert (Associate Editor) Leadership positions in professional societies American Society for Reproductive Medicine (Member Practice Committee)


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