Researchers at the National Institutes of Health (NIH) have found that low doses of aspirin every day does not prevent pregnancy loss among women who’ve had one or two previous pregnancy losses.

Past studies have shown that low-dose aspirin could potentially help women who had experienced pregnancy losses, but this is the first to counter that claim. “Our results indicate that aspirin is not effective for reducing the chances of pregnancy loss in most cases,” Dr. Enrique Schisterman, chief of epidemiology at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), said in a NIH press release.

According to Schisterman, additional research will investigate whether women who had one recent pregnancy loss had an increased pregnancy rate during aspirin therapy. Among the women participating in the study — most of whom were between the ages of 18 and 40 and were predominantly white — 78 percent taking aspirin became pregnant, as opposed to only 66 percent among those who took the placebo. Women were given either aspirin and folic acid, or simply a placebo and folic acid.

Because of this, the researchers believe it may be possible that aspirin therapy could help fertility. The authors hypothesize that aspirin may have boosted conception rates by an increased blood flow to the uterus. Further research is needed to find out whether aspirin therapy can be used to improve fertility among other types of women as well — such as those who can’t become pregnant due to an embryo failing to implant in the uterus.

It may sound counterintuitive, especially since aspirin has previously been considered dangerous — not only for pregnant women, but for others, too — especially if it’s taken every single day. For example, taking aspirin every day could increase the changes for bleeding, particularly if a person is older.

But some studies have pointed to the notion that aspirin may actually help pregnancy outcomes among people with recurrent pregnancy loss. One study published in 2013 found that women who took low-dose aspirin before conceiving a child actually became pregnant more quickly than women on placebo. However, the researchers cautioned the public, saying that “it’s premature to have a take-home message for the everyday clinic.” The NIH has taken a stand on the issue, stating that aspirin really doesn’t help — though more research is needed to be entirely conclusive.