But how did she manage the feat? A source tells ET that everything about her pregnancy, delivery and announcements was very meticulously thought out and executed.
“Kylie really enjoyed her time out of the spotlight. It was really her first time [out of the spotlight] since she was a little kid," the source explains. "You have to remember, Kim, Khloe, and Kourtney all lived normal teenage lives, even into their early twenties. But Kylie didn’t have that, so she wanted to make the most of this time."
The source adds that Kylie knew her life was about to change, so she wanted to just take a moment to herself before inviting the public into it again.
"They’ve really limited who is around Kylie during this pregnancy," the source says. "They were strategic about not being photographed and strategic about who they told."
According to the source, some of the ways they kept the baby's birth a secret likely included decoy cars, as well as making sure Kylie's patient rights were enforced.
"She likely used a decoy car, something the Kardashians have done a lot when trying to avoid being followed or photographed," the source says. "They enforced the legal rights of patients, it’s against the law to release information about patients to the public, Kris no doubt would have made sure they upheld their responsibilities to their patient."
And above all else, privacy.
"They told no one," the sources says. "They kept the news very private, only immediate family knew. They didn’t start a text chain with family and friends until after Kylie made the announcement."
As for a baby name, the source tells ET that a name has been chosen, but nothing has been released yet.
Moving forward, the source says that Kylie plans to raise her child in a very hands-on way, sharing, “ As for nannies, Kylie will definitely be very hands-on and will rely on family for support, not outside help."
Watch the video below for more on Kylie's new baby.