BUFFALO, N.Y. – The Effects of Aspirin in Gestation and
Reproduction (EAGeR) medical trial has found that, in general,
low-dose aspirin is not beneficial for future pregnancy outcomes in
women with prior pregnancy loss.
However, in women with one pregnancy loss within the previous 12
months, there did appear to be a benefit.
Jean Wactawski-Wende, PhD, professor in the Department of
Epidemiology and Environmental Health in the School of Public
Health and Health Professions at the University at Buffalo, is a
principal investigator of the Buffalo EAGeR trial and co-author of
the study “Preconception low-dose aspirin and pregnancy
outcomes: results from the EAGeR randomized trial.”
It is published in the current issue of The Lancet.
She points out that many health care providers prescribe
low-dose aspirin therapy for women who have had a pregnancy loss,
and who would like to get pregnant again.
“The effectiveness of this treatment has not been proven,
however, which is why this study was undertaken,” she
Wactawski-Wende says, “This was a multicenter,
double-blind, placebo-controlled trial. It found that, over all,
treatment with low-dose aspirin initiated prior to pregnancy does
not increase the rate of live births or reduce the rate of
pregnancy loss in women with a history of one to two previous
“One subgroup studied, those with a single documented loss
at less than 20 weeks gestation during the previous year, did
experience a higher pregnancy rate and live birth rate,
however,” she says.
“Our conclusion is that preconception-initiated, low-dose
aspirin is not significantly associated with live birth or
pregnancy loss in women overall,” she says, “and the
study does not support the general use of low-dose aspirin to
decrease the risk of pregnancy loss.”
She says the research team is planning further exploration of
these findings to better understand them. That may include studies
to explore mechanisms by which the intervention worked by using
stored samples of blood and urine collected during the study from
The authors note that the loss of a pregnancy is a fairly common
event, estimated to occur in up to 30 percent of all conceptions.
Women who have had a pregnancy loss are at increased risk of having
a subsequent loss and other adverse pregnancy events.
Wactawski-Wende says that while the pathophysiological
mechanisms that lead to adverse pregnancy outcomes are not fully
understood, decreased blood flow and increased inflammation are
postulated to have important roles.
“Preconception use of low-dose aspirin has been found to
improve endometrial growth and vascularization in women undergoing
in-vitro fertilization, and to increase blood flow and reduce
inflammation in the reproductive organs,” she says.
“It was hypothesized, therefore, that
preconception-initiated, low-dose aspirin might positively affect
downstream pregnancy outcomes during that crucial treatment window.
Until now, however, that possibility had not been extensively
To test the hypothesis, researchers enrolled 1228 women between
18 and 40 years old to participate. Of those, 1078 completed the
Participants were randomly assigned to receive either low-dose
aspirin or placebo, roughly half to each group. They were followed
for up to six cycles during which they attempted to conceive. All
women in the study received folic acid.
The outcome was that 308 (58 percent) of those in the
low-aspirin group had a live birth, compared with 286 (53 percent)
of those in the placebo group. Pregnancy loss occurred in 68 (13
percent) of the women taking low-dose aspirin and in 65 (12
percent) of the placebo group.
Adverse events were similar between the two groups. One adverse
reaction, increased vaginal bleeding, was associated with low-dose
aspirin but the bleeding was not associated with pregnancy
“Women should talk to their health care providers before
considering low dose aspirin or any other medication while
attempting to get pregnant or during pregnancy,”
Wactawski-Wende says. “But based on this trial, general use
of low-dose aspirin is not recommended.”
This study was funded by the Eunice Kennedy Shriver National
Institute of Child Health and Human Development (NICHD) of the
National Institutes of Health.
The work was conducted by researchers at UB, NICHD and
University of Utah Health Sciences Center, in Salt Lake City, Utah;
the University of Haifa, in Israel; The Commonwealth Medical
College, in Scranton, Pennsylvania; and the University of Colorado,
in Denver, Colorado.
Additional UB investigators include Richard W. Browne, PhD,
associate professor, Department of Biotechnical and Clinical
Laboratory Sciences, School of Medicine and Biomedical Sciences,
and Moeen Abu-Sitta, MD, clinical associate professor, Department
of Obstetrics and Gynecology, School of Medicine and Biomedical
Sciences. Browne and Abu-Sitta are also research associate
professors in the Department of Epidemiology and Environmental
Health, UB School of Public Health and Health Professions.