It should’ve been a fun holiday activity—taking her kids to a local Polar Express train ride. Instead, Jennifer Parks’ excitement dimmed slightly as she drove past not one, not two, but three pharmaceutical facilities in her area that she knew were hiring.

With a degree in microbiology, Parks worked in pharmaceutical manufacturing until the birth of her oldest seven years ago. And she loved it. But now as a mom of three—her youngest is only 21 months—Parks is a reluctant stay-at-home mom with no real sense of when—or if—she’ll be able to rejoin the workforce.

“They're right around the corner, why am I not working?” Parks recalls remarking as she drove past the companies late last year. “I loved working. I loved my job. I've never felt a greater sense of self worth and pride than when I worked,” Parks tells Fortune. “I love my kids too, but I'm so tired of having them cry about the oatmeal that they asked for.”

The biggest reason this well-qualified woman isn’t in the workforce? Parks can’t find affordable childcare coverage. “When we started running the numbers, there was basically no way that we could really cut childcare that made it cost under $100,000.” And realistically, Parks doesn’t think she could ask for a salary that high.

With her husband’s job as an investment banker covering the family’s considerable living expenses in Maplewood, N.J., Parks says to take a job outside the home, she’d need to earn enough to pay for full-time childcare. “I have to cover the cost,” she says. “My ideal goal would be enough to pay for childcare and max out retirement, and I feel like that's even like—why don't I just wish for a pony, too?

“I loved working and want to have a professional life again, but the costs, logistics, and the high likelihood of needing to be in-person [working] at pretty set hours, makes it all feel unrealistic,” Parks says.

Like Parks, millions of Americans—mostly women—grapple with the financial breaking point of childcare. Around 4.5 million Americans remained unemployed in January because they were caring for children not in school or daycare.