Researchers publishing in the journal Vaccine revealed new research that hints at a possible association between pregnant women taking the flu vaccine and an increased risk of miscarriage. However, scientists are urging caution in interpreting the results, and are encouraging pregnant women not to go unvaccinated.

According to the Washington Post, “It’s the first study to identify a potential link between miscarriage and the flu vaccine and the first to assess the effect of repeat influenza vaccination and risk of miscarriage. The findings suggest an association, not a causal link, and the research is too weak and preliminary, experts said, to change the advice, which is based on a multitude of previous studies, that pregnant women should get a flu vaccine to protect them from influenza, a deadly disease that may cause serious birth defects and miscarriage.

But the small-scale study, which found a slightly higher chance of miscarriage in women who received a flu vaccine 2 years in a row that included a specific strain of the virus, is littered with “possible,” “may,” and “could,” Science Magazine reported.