Many months into the pandemic, we’re beginning to learn more—and in more detail—about how the Covid-19 is disrupting the health and wellbeing of specific populations. Yet for pregnant women and their unborn children, such information has been inconsistent, inconclusive, and altogether lacking.

In late April, a group of researchers sounded a call to action in the Lancet imploring their peers, and the public health authorities they serve, to fill this glaring knowledge gap. Progress has been made since then, most notably in the form of a study published last week that pronounced it unlikely for the Covid-19 virus to be transmitted from mother to womb. Still, much remains unknown, and in the meantime, vigilance is needed.

While no studies to date have shown that being pregnant increases the risk of Covid-19 infection or, once infected, severe symptoms, reports have started to trickle in that paint a more troubling picture. A case study published by JAMA in late April, for instance, describes a Covid-19 patient who had a spontaneous miscarriage in her second trimester. The placenta tested positive for the Covid-19 virus, prompting the question of whether infection had a role to play in inducing the adverse outcome.

Adverse pregnancy outcomes documented during the previous two coronavirus pandemics, SARS and MERS, can’t be discounted either. One report suggests that pregnant women hospitalized with SARS were more likely to experience complications like sepsis and renal failure, require longer hospital stays, and end up in intensive care.

We also know that pregnancy weakens the immune system, making pregnant women more susceptible to respiratory infections more broadly, not just those caused by coronaviruses. Such was the case during the 2009 outbreak of H1N1 influenza in the United States. According to another Lancet study, pregnant women developed severe pneumonia and deteriorated to the point of needing mechanical ventilation at higher rates than nonpregnant women. Even high fever, a common symptom of Covid-19, is a harm for pregnant women to be wary of. Developed in too early a stage of pregnancy, high fever can lead to birth defects.

Other risks don’t involve infection itself, but the public health measures we’ve adopted to prevent it. Stay-at-home orders and general fears of coming into contact with Covid-19 patients have prevented some women from completing their prenatal checkups as scheduled. Even more worryingly, these same conditions can keep women facing domestic violence from seeking help or safe refuge.

To study and understand the full extent of the impact that Covid-19 and ensuing countermeasures have had—and will continue to have—on pregnant women around the world, research efforts will have to broaden in scope to include risks both medical and social. They will also have to expand across space and time, aiming for a global reach befitting of a global crisis.

The researchers behind the Lancet article say as much, and yet many of their recommendations have gone unaddressed. They call for more expansive strategies of data collection that would track the impact of Covid-19 over the course of a woman’s pregnancy and into her child’s infancy. They also point to existing data reserves, like pregnancy registries, and research networks, like those formed to study the impact of the Zika virus on pregnancy, that could be mobilized to make the effort truly global.

This pandemic isn’t likely to be the last, or even the most virulent. Understanding its impact on pregnant women won’t just benefit the children born in the throes of Covid-19, but their children’s children. We need more data transparency, coordination, and cooperation between countries on this urgent matter—or we risk leaving future mothers-to-be vulnerable once more.