Larry Hand

October 30, 2013

BOSTON — A group of women who took low-dose aspirin prior to conception took less time to become pregnant compared with women who took a placebo, according to results of the Effects of Aspirin in Gestation and Reproduction (EAGER) trial.

"It was a surprising finding, but it's premature to have a take-home message for the everyday clinic," Robert Silver, MD, chief of maternal-fetal medicine, from the University of Utah in Salt Lake City, told Medscape Medical News. "Our study was designed to assess whether preconception treatment with low-dose aspirin would reduce the risk of pregnancy loss in women with previous pregnancy loss, and the answer is it doesn't."

Dr. Silver presented the results of the EAGER trial here at the American Society for Reproductive Medicine (ASRM) 69th Annual Meeting.

First results, presented at a late-breaking trial earlier this year at the Society for Maternal-Fetal Medicine meeting, suggest that low-dose aspirin, because of its anti-inflammatory effects and its effects on blood flow improvement, has the potential to aid in reproduction.

The researchers conducted a prospective, randomized, double-blind, placebo-controlled trial in which they recruited women aged 18 to 40 years with 1 or 2 prior pregnancy losses who were still trying to conceive.

Recruitment was initially restricted to women with 1 documented loss at less than 20 weeks. However, Dr. Silver told conference attendees that owing to slow enrollment, researchers added another group of women who had 1 to 2 previous losses, irrespective of gestational age or the amount of time since loss.

Trial participants at baseline were mostly non-Hispanic white, well-educated women. Household incomes exceeded $100,000 annually for 40% of them.

The women were randomly assigned to receive either low-dose (81 mg) aspirin or placebo through 6 menstrual cycles. All patients also received 400 μg of folic acid. If patients had a positive pregnancy test or confirmed pregnancy, treatment and follow-up continued through the pregnancy.

Daily low-dose aspirin use led to a significant decrease in time to pregnancy among women with prior losses (P = .04) and to a shorter time to clinically confirmed pregnancy among women with a single documented loss at less than 20 weeks during the past year (P = .02). However, differences were not significant in the broader cohort.

Table. EAGER Trial Results

Treatment Group Positive Pregnancy Test Clinically Confirmed Pregnancy

Low-dose aspirin (n = 615)

402 378

Placebo (n = 613)

374 350


"We found out that in a subset of women, low-dose aspirin seemed to either increase their probability of getting pregnant or decrease their chances of very early losses," said Dr. Silver. "This is really an exploratory finding, and one that we're excited about, but it needs more research. It is not something we would recommend changing clinical care at present."

This is really an exploratory finding, and one that we’re excited about. Dr. Robert Silver

Emmanuel Bujold, MD, from the Université Laval in Quebec, Canada, told Medscape Medical News earlier this year that most experts believe that aspirin does not improve conception or reduce the risk for miscarriage. "But if it does, the effect is very small," he said.

"Overall, in the women in the trial, who had 1 to 2 prior losses, they found no difference in live birth rate between the low-dose aspirin group and the placebo group. It was only when they did a subgroup analysis that it became significant," he pointed out.

This is not the first trial to look at the effect of aspirin before conception, Dr. Bujold noted, and "it is likely not effective, as the EAGER study results suggest."

This study is funded by the Intramural Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health. Dr. Silver and Dr. Bujold report no relevant financial relationships.

American Society for Reproductive Medicine (ASRM) 69th Annual Meeting: Abstract 327. Presented October 16, 2013.


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