The US’s Food and Drug Administration has taken a landmark step to encourage pharmaceutical companies toward “judicious inclusion of pregnant women in clinical trials and careful attention to potential fetal risk,” by releasing a set of safety and ethical recommendations to guide pharmaceutical companies in doing so.

Until now, in the absence of such guidelines, drug manufacturers have eschewed testing on pregnant women. The few medications that are already approved for use during pregnancy are often aimed at treating conditions specific to pregnancy. As for the rest of medication an adult woman might require — from over-the-counter antacids and cold and cough medicine to prescription medicines for high blood pressure, epilepsy and depression — the research into effects and dosage during pregnancy “is pretty impressively minimal,” Dr. Catherine Spong, the task force head, told STAT News last year.

Which means pregnant women and their doctors have little to no guidance around what medicines were safe, and in what dosage. Because mothers share a blood supply with fetuses, any medication the mother takes could potentially effect the fetus; and because pregnancy engenders all sorts of physiological changes, recommended adult doses could become to little or too much for effective treatment.

“I was on Zoloft for many years before I became pregnant with my first,” one woman told the federal task force tasked with drafting guidelines for including pregnant women in drug trials. “Both my psychiatrist and OB/GYN would not give me an answer about if I should continue to take it.”

In the absence of evidence, pregnant women have historically had to make their own judgment call about whether to risk continuing critical medicine, or whether to risk discontinuing it. And not just the 10% of pregnant women who require medication to treat their chronic medical condition; 40% of women choose to take some form of medication during pregnancy, with no real evidence of potential risks and rewards to guide their decision.

The FDA guidelines are not the first of their kind, but they are likely to be the most effective going forward. Given that the US is home to 45% of the world’s pharmaceutical industry any move to include pregnant women in clinical trials there will have an outsized effect for pregnant women globally. Still, soon is relative; medications often take years to go through clinical trials. But that is likely to be a shorter time than women have spent guessing at whether and at what amount the medication they need will effect their unborn child.