Women undergoing IVF are often told that a daily aspirin will help boost the odds of success, but recent research doesn't agree.
A review, reported in the Cochrane Library, combined the results of 13 international studies and discovered that a low daily dose of aspirin had no clear effect on IVF pregnancy or birth rates.
"Couples undergoing IVF often feel so desperate that they are prepared to try anything that may improve their chances of conceiving," said Charalambos Siristatidis who led the research. "Given the current evidence, there is still no basis to recommend that women take aspirin to help them become pregnant," he said in a statement.
What are the facts?
In theory, aspirin could improve IVF success
by boosting blood flow to the ovaries and uterus, and also might help by preventing blood clots in the placental vessels.
But studies have come to mixed conclusions.
There is a small majority of women who have repeat miscarriages because of problems with blood clotting, said Roger Lobo, a professor of obstetrics and gynecology, who was not involved in the review.
If a woman undergoing IVF has blood-clotting issues, then aspirin or other anticoagulants may help. But for most women having IVF, "it's really the embryo quality that's the major factor, so I'm not surprised that aspirin shows no benefit overall."
The studies in the review included 2.653 women undergoing IVF. The trials randomized women to take 80 to 100 milligrams of aspiring per day, with the other half assigned to a no-aspirin "control" group.
In most studies, women started taking aspirin at the beginning of the IVF process. The duration of the treatment varied from study to study.
One of the larger studies that looked only at pregnancy rates did not suggest a benefit. Of 300 women, the pregnancy rate among aspirin users was 45%, against 28% of the women not on aspirin.
But when researchers combined the results of different studies, they found no overall effect on women's pregnancy or birth rates, or on their risk of miscarriage.
Lobo too noted that many couples undergoing infertility treatment
are desperate to try anything that could raise their chances of having a baby, even in theory, but stressed that even low-dose aspirin can have risks, including gastrointestinal bleeding.
"Based on the evidence, there really appears to be no benefit from using aspirin. And if you add to that the fact that there are risks, it probably shouldn't be done," he said.
Have you tried taking asprin during IVF?