Think you'll come back to work a frazzled mess? Nah. You'll return to your career more capable than you were back when you waddled out still pregnant. That's because in the interim, the world's hardest boss (that would be your baby) has just put you through boot camp. Thank you, sir, may I have another? My prediction? You'll be better at...
Pivoting: There will be times, of course, when you need pure concentration on a heads-down project at work, or when you need to be 100% focused on your family. But the other 23 hours of your day? Those will be all jumbled up. At work, you'll get a call about the baby. At home, you'll get an email from a client. And as soon as you get comfortable bringing your whole self to work—mom identity and all—the pivoting starts to feel less like it's bad on your knees, and more like it's some supercharged dance all over the court in a cute tennis skirt.
Working quickly and efficiently: It's tempting here to say something about how your skills at the changing table prepare you for sudden shit-storms (and indeed, Mark Zuckerberg even bragged about his sub-30-second diaper change). But most new working moms will tell you they get faster and smarter about how they work because, for the first time, they have a quitting time. Not a like-to-get-out-by time. A hard stop, after which their daycare charges them money, or their nanny dips into the freezer stash of breastmilk, or they don't make it home in time to read The Runaway Bunny. You will be shocked by how much you get done. Quickly. And well.
Saying no—and saying yes: The saying no part is probably no surprise. When life gets fuller, you simply have to decline some invitations, some projects, some meetings that just aren't crucial. But your Yes List—the things you do choose to take on—becomes hugely validating. Those are things that you know you've truly considered and designated important. And therefore? You will nail them.