“There’s an unease” among young women correspondents in the NBC Washington bureau who would like to become moms someday, said a producer there who asked not to be identified. “No one wants to be the test case, because it hasn’t been a common concern, and people are so committed to their jobs, they’re worried about being able to juggle it all.” (CBS News, NBC News, ABC News, and CNN did not respond to requests for comment on this story.)

Being a TV-news correspondent is tough for anyone, but it presents structural challenges that are particularly rough on moms. For one, the industry is bound to the nature of news, which is unpredictable, 24/7, and happens everywhere. You’re often racing out of town without much warning. Moms are expected to do their job like it’s their only responsibility, even though they’re also working the mom shift. Covering a forest fire or a mudslide is rarely compatible with being home for back-to-school night.

If you decline an assignment, you may be labeled a problem or deemed not to be a team player. Managers judge correspondents partly based on how often they’re on air. Whether on cable or a network, airtime is a marker of success—and that metric runs headfirst into the reality of motherhood. “You sacrifice so much to get there, and there’s never a point where you can stop sacrificing,” said a former network producer who, like most of the other women I spoke with, asked to remain anonymous to avoid angering their current or former employers. “That is the culture. Who is working the hardest? Who is working the most? There’s something about TV news where you’re supposed to live the job, and that’s all people care about; otherwise they question your commitment—and you’re totally replaceable.”

In this business, perhaps more than any other, out of sight really is out of mind.

Maternity leave, of course, means time away from the camera. The Fox Business Network anchor Trish Regan has spoken extensively about her regrets over not taking full advantage of her maternity leaves, but she felt that that was what she had to do to succeed. She took six weeks with her twins when she was at CNBC and only three weeks with her son when she was at Bloomberg Television, though the companies’ policies entitled her to more.

“The pressure [to come back before my leave was up] was certainly self-inflicted in that I’m driven and ambitious and wanted to succeed,” Regan told me. “But at the same time, I was very aware that if I was gone for that amount of time, I was perhaps replaceable with either a man who could do the job or a woman who wasn’t having a baby. These were very real concerns of mine, and there was no one in my environment at either of those networks [who] was encouraging me to think otherwise.”

Read: What’s the matter with TV news?