On Thursday night, Cardi, whose real name is Belcalis Almanzar, posted on Instagram that she is pulling out of Mars' 24K Magic World Tour Finale, which is set to kick off on Sept. 7.
In part, Cardi B said that she thought that six weeks between giving birth and the tour start would be "enough time for me to recover mentally and physically."
She also said she thought she could bring new daughter Kulture Kiari with her on the road, admitting that she "underestimated this whole mommy thing."
"Not only am I just not ready physically, I'm not ready to leave my baby behind since the doctors explained it's not healthy for her to be on the road," she posted on her Instagram page, which boasts nearly 29 million followers.
She concludes her statement addressing fans.
"I hope you guys understand that this decision has been the hardest to make but I have to do what's best for myself and my baby!"
On July 10, the 25-year-old and husband Kiari "Offset" Cephus welcomed their new daughter.
In response, Mars said, "Most important thing is you and your family's health. I know the fans will understand. I also know we'll share the stage when the time is right."
Cardi B was set to go on tour in support of her debut album Invasion of Privacy, which was released in April.