In the first week of widespread self-isolation throughout the United States, Silicon Valley startups—and especially female founders—raced to solve one of the biggest problems in the country’s response to the coronavirus pandemic: the lack of available testing for COVID-19.

But on Friday, the Food and Drug Administration made an announcement that brought two of those efforts to a halt. While startups Nurx and Carbon Health had planned to supply at-home tests by leveraging existing relationships with CLIA-certified labs, they quickly pressed pause on those efforts after the FDA’s new guidance on emergency response to coronavirus testing made at-home tests against the government’s rules. (An FDA spokesman says, “The FDA sees the public health value in expanding the availability of COVID-19 testing through safe and accurate tests that may include home collection, and we are actively working with test developers in this space.”)

However, a third startup, Everlywell, quickly pivoted from at-home testing to simply selling tests that health care providers can order and use on their patients or other health care workers.

Nurx—known for providing birth control via telemedicine, but well positioned to dive into the COVID-19 response because of its other stream of business: providing the HIV prevention medication PrEP—was founded by Hans Gangeskar in 2015 but is now run by CEO Varsha Rao. Everlywell, which does at-home medical testing for conditions including the flu and high cholesterol, is in the hands of founder and CEO Julia Cheek.

So why were women-led companies at the head of the pack—and perhaps even too close to the front, some would argue—in designing Silicon Valley’s response to a global pandemic?

“Women are often the centers of health care planning in their homes—they make 75% of health care decisions for their families,” Cheek, of Everlywell, argues. “For women running health care companies, we have to step in, and we want to lead for the community.” Adds Rao: “A deep commitment to public health is something that speaks very much to female leaders.”

The subcategory of women’s health has encouraged many female founders to enter the field of digital health; in 2019, women’s health companies raised just over $1 billion, according to CB Insights.

The female founders responding to the pandemic aren’t just concentrated in the highly regulated area of coronavirus testing. Ava, a startup that produces a wearable device used to help women track measurements like body temperature as they try to get pregnant, offered its hardware to researchers who want to undertake a study of the coronavirus and possible early detection (the device is not approved for individual tracking of coronavirus symptoms). Ava cofounder and CEO Lea von Bidder says she has heard from two governments interested in studying symptoms among either their general population or health care workers. “If you start a health care company, generally those are vision-oriented people,” von Bidder says. “Everyone who started a company for the greater good will look at this and say, How can I contribute?”

The fertility space, another booming area for women’s health startups, has seen a significant hit to its primary business as elective procedures come to a halt nationwide.

Kate Ryder, founder and CEO of the women’s telehealth company Maven, says that while the demand for her company’s fertility services is down, it has seen an explosion in need for basic telemedicine as women become reluctant to visit doctors and hospitals in person. Pregnant women are using the Maven platform to ask questions like, “Should I be going for runs if coronavirus is airborne?” and “Does COVID-19 transfer to breast milk?” The company has been conducting webinars in which its users can ask questions about the coronavirus and has begun offering a short-term six-month contract for employers looking to provide telehealth benefits to their employees during the crisis.

Other fertility companies, like Tammy Sun’s Carrot Fertility, have released resources on topics like the coronavirus’s effects on adoption and fertility treatments.

For the female-founded health care companies that were hoping to provide at-home testing, the stakes are higher. Nurx says the company will “continue full speed ahead to ensure we are supporting our patients outside of COVID-19” and that it has seen a 40% increase in demand for birth control prescribed via telemedicine since the U.S. coronavirus crisis began. Rao declined to comment after halting the company’s at-home tests.

Everlywell is pressing on, emphasizing that it is no longer providing an at-home service and that its tests—available for $135 each to health care providers—use the same nasopharyngeal swab as government-provided tests. (Nurx’s test had planned to use a different form of self-collection of the sample.)

With FDA guidance rapidly changing, there’s a chance at-home tests from private companies could be back on the table soon. But for now, Cheek still hopes her startup will be able to fill some of the gap.

“I see women leaders staying calm and collected through crisis,” she says. “We’ll soon be seeing their collective response.”

More coronavirus coverage from Fortune:

—Why the extraordinary dollar surge spells more trouble for the global economy
—Japan finally admits coronavirus might disrupt Tokyo 2020 Olympics
—Which stores are open—and closed—during the coronavirus pandemic in the U.S.?
—How to defer your mortgage payment due to coronavirus
—How Emmy season is proceeding, with caution, amid the coronavirus crisis
—Listen to Leadership Next, a Fortune podcast examining the evolving role of CEO
—WATCH: World leaders and health experts on how to stop the spread of COVID-19

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