Two long-used drugs may be able to help women at high risk of miscarriage and other pregnancy complications. Scientists in Japan have found evidence in a small study that low dose aspirin, either alone or in combination with heparin (a common blood thinner), can prevent a specific type of recurrent pregnancy loss.

Miscarriage (losing a pregnancy in the first twenty weeks of gestation) is a relatively common occurrence, affecting 10% to 20% of known pregnancies. But a much smaller percentage of women, fewer than 5%, experience repeated miscarriages, defined as having two or more in a row. A team of researchers at Kobe University and elsewhere in Japan now believe they’ve found a way to prevent least some of these especially tragic cases.

In its earlier work, the team found that many women with recurrent pregnancy loss—about 20%—carry autoantibodies targeting a certain protein found on the surface of many cells, including cells in the uterus important to supporting fetal gestation, known as beta-2-glycoprotein I (β2GPI). Other research had shown that anti-beta-2-GPI antibodies can play a part in causing antiphospholipid syndrome (APS), an autoimmune disease known to raise the risk of pregnancy loss. But the researchers had also found that some women with recurrent pregnancy loss can carry similar antibodies that target beta-2-GPI even without having APS.

Low-dose aspirin, typically used alongside heparin, is already thought to help reduce the risk of miscarriage in women with APS. So the researchers tested whether the same preventative treatment could also help women without APS who had these anti-beta-2-GPI antibodies.

Their study, published Wednesday in the journal Frontiers in Immunology, involved 47 pregnant women with recurrent pregnancy loss who tested positive for the antibodies they had previously discovered. Of these, 39 were given low dose aspirin and/or heparin, while eight were not. Overall, over 80% of women in the treatment group had a live birth, compared to 50% of the non-treated group; these women also had a much lower risk of other pregnancy complications.

“The sample size was rather small, but the results still clearly show that a treatment with low-dose aspirin or heparin is very effective in preventing pregnancy loss or complications also in women who have these newly discovered self-targeting antibodies,” said lead study researcher Tanimura Kenji, an obstetrician at Kobe University, in a statement from the university.

Some of the women who had these antibodies also tested positive for APS, potentially complicating the results. But the researchers found that women without APS had an even higher rate of successful pregnancy when treated with these drugs (over 92%). Kenji notes that anti-beta-2-GPI antibodies may also help cause infertility and other health conditions in women, such as arterial thrombosis, so their findings could have wider implications there as well.

In any case, more research and larger trials will be needed to confirm this work. But given how devastating the repeated loss of a potential child can be to a mother and family, finding a simple, affordable preventative treatment for these cases would be incredible.