Yahoo’s new CEO, Marissa Mayer, tweeted earlier this week that—as promised—she’s gone back to work just a couple of weeks after giving birth to her first baby. To me, that sounds really hard, but she’s anxious to stay in the rhythm of things at work, so more power to her. Still, her choice to forego a full, paid maternity leave does call attention to the fact that most working women in this country don’t have the choice.

We at Working Mother have been pushing a campaign to mandate paid parental leave in the U.S.—we shared the disturbing knowledge in our October/November 2012 issue (a year ago) that the United States is one of the only developed countries that does NOT have a policy for all new moms, so we joined with National Partnership for Women and Families in collecting signatures on a petition to Congress asking for a national paid leave insurance program like the one California instituted a decade ago. It works like disability insurance—employers pay into a fund and then workers get paid from the fund when they go on leave; their companies don’t have to keep paying their salaries, so they can hire temporary workers to fill in. In California (and pretty much every developed country in the world except the U.S.), it’s a win-win. (Yahoo’s headquarters is in California, so we know for sure that Mayer isn’t eschewing maternity leave because she’s worried about an extended time with no pay coming in!)

Since we announced this campaign, we’ve put our money (and time and energy) where are mouths are. In the year that’s passed, four of my co-workers have become working mothers for the first time: Michele Siegel and Kristen Willoughby, who work on the Best Companies initiatives with me, had baby girls, as did magazine staffer Irene Kwon; Angela Johnson Meadows, editor-in-chief of our sister organization, Diversity Best Practices, adopted a boy. Plus, two colleagues in our conferences and marketing departments, Jacqueline La Brocca and Jessica Goldman, both had second babies!

It’s fun to work in the midst of a baby boom, except when valuable people go off on maternity leave. It’s disruptive. It’s difficult. We sometimes wondered whether we could get by without our wonderful colleagues; we struggled and stressed and occasionally took an extra day or two to resolve an issue or problem. We (laughingly, good-naturedly) cursed their babies, just before passing around the latest photos to ooh and aah over.

We felt the pain that opponents of mandated maternity leave complain about: It was time-consuming and expensive to hire people to fill in. We all had to pitch in to cover the work.

But then they came straggling back. Some were more sleep-deprived than others. Some took a few extra personal phone calls at the office. Most started using more flex, working from home on a regular schedule to save commuting time. But without exception, every single one of them picked their work right back up where they’d left off.

I know that coming back to work felt like a big adjustment to them, but we, their co-workers, didn’t feel a thing except relief and happiness. Kristen Willoughby started sending email blasts to 100 Best winners on her first day. Michele Siegel dove into creating benchmarking reports and executive summaries. Irene Kwon started posting slide shows on workingmother.com. The pain of a few months without them was lifted. We appreciate them all even more now than we did before we tried to get their jobs done without them, but we’re so pleased and happy that they’ve returned and that we didn’t have to search for, hire and train full-time replacements for them.

And that’s kind of the point of not only our paid parental leave campaign, but also our constant push-push-pushing on all the issues that affect working moms and everybody else who has a life outside of the office. A limited period of time spent making adjustments and picking up a little slack for co-workers who are dealing with time-consuming issues at home, or a small investment in extra help while such a person has a chance to care for his or her new baby or sick parent, won’t seem significant once that person is back at work doing the job he or she knows how to do best. And if he or she needs to do some of that work from home, or at odd hours, it’s still better than not having that experienced, trained, known person do the work.

We at Working Mother Media are thrilled to have so many new babies in our extended family! And we’re thrilled to have been able to help our co-workers transition from being workers to being working moms.

So that every working parent can have the option of welcoming a new child without having to worry about a paycheck, sign our petition for paid parental leave at workingmother.com/paidleave!

Krista Carothers is senior research editor at the Working Mother Research Institute and Working Mother magazine.