On August 26, Amy Sterner Nelson was speaking at an event, and needed to rely on a stranger to stash the bags of breast milk she'd recently pumped. When she located them later, in a company refrigerator, they had a Post-It note affixed, reading simply: "CEO's Milk."

Nelson snapped a photo, and posted it on Instagram. "I am a CEO. And it is my milk. And those two words together mean the world to me," she wrote. "If my doing this... can shine a light for any other mother, it's all worth it. We can do both. I promise you." Nelson now has 14,500 Instagram followers, a number that has quadrupled since she began opening up online about her life as both the founder of co-working business The Riveter and the mom of four girls under the age of 5.

Nelson's recent push for work-life transparency isn't unique: A growing number of female founders are broadcasting parts of their life not only to demystify their challenges, but also to directly answer queries and mentor their cadres of followers. By doing so, they've hit upon an effective method to scale the reach of their mentorship efforts.

"I could spend a day of my week mentoring people--but the reality is I don't have time to do that," says Katrina Lake, the founder of online personal styling company Stitch Fix, who in 2017 became the youngest woman chief executive to take a U.S. company public. Instead, she can spend a few moments on Instagram, answering a DM or heart-ing somebody's picture. Most weeks she hosts an ask-me-anything session on Instagram she calls Mentoring Mondays. "To be honest, it's a really low-lift way for me to connect with people," she says.

Nelson founded The Riveter after she had her second child, and had felt that she was at risk of being pushed out of her job as a corporate litigator. She's grown her inclusive co-working startup from one location in Seattle to 10 across the western United States in two years, and has her sights set on scaling to 100 locations by 2022. Now she gets a lot of messages from her Instagram followers about how she pieces together the puzzle of raising four small children while running a fast-growing business.

"The messages make me want to stop and cry, because these folks really haven't seen anyone do this before," she says. "There's an insane scarcity of women who are building scalable companies--and of women starting companies while having kids."

Nelson made the conscious decision this year, while pregnant with her fourth child, to turn the camera on herself more, film videos for Instagram Stories, and field as many questions as she could from her followers--whether about life, entrepreneurship, teaching her kids to swim, or practically anything else. 

"I sure did not see examples of how to do this when I was starting out in my career--or even when I was trying to keep a job while breast pumping in the office," she says. "I have this platform now, so I pledged to myself that I would show the reality of how it works."

Nelson posts about her postpartum workouts and milk-storage tips, but also actively answers questions from her followers during her periods of downtime. The roughly 30-minute chunks of Q&A pop up several times a month on her Instagram Stories. On her regular Instagram posts, she strikes a candid tone.

Other entrepreneurs take a more regimented, scheduled approach to their virtual mentorship. Trinity Mouzon Wofford, the founder of superfood powder company Golde, answers questions every couple of weeks in video format, which she stores on her Highlights on Instagram. Wofford calls the Q&As "Office Hours," and says they are hugely popular with her 6,500 followers.

The way these founders use Instagram to answer questions from their followers is easy to replicate: When posting a photo or video to Stories, you select a sticker called "questions." Then, instead of asking viewers to answer a specific question, as the app prompts, you solicit questions by typing a variation of "Ask me anything!"

In one recent Mentoring Mondays session, for example, Lake answered questions about how she found her first 50 customers ("friends and family") and her tips on public speaking ("Practice helps a LOT. Take advantage of chances to present whenever you can, and ask for feedback"), in addition to offering up advice for maintaining cash flow when declining to work with institutional investors. She doesn't assume everyone watching needs cash-flow pointers; rather she hopes she can show her followers--particularly young women--that her position is not out of reach.

"Being a CEO of a public company is a unique job--but, also, it's just a job," she says. "I want to demystify what it's like. If I can help other people think: Oh, I could do that!, that's really powerful."

Correction: An earlier version of this article misspelled the maiden name of The Riveter founder Amy Sterner Nelson.