"We're confirming the news, baby #4 is coming soon!" the 27-year-old reality star captioned a photo of her sitting on her bed with her three sons and the baby's sonogram.
At "almost 16 weeks," Kail said she's had a hard time adjusting to her fourth pregnancy.
"It's been a rough few months this time around," she explained. "I've had nausea, morning sickness, and absolutely no energy. This week I'm starting to feel a bit better and I'm really hoping it stays this way!"
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She went on to tag Peanut, the social network that connects women on topics such as fertility and motherhood, noting that the company "has been an amazing support for me since I found out I was pregnant again."
"Going through nausea and morning sickness while trying to keep the news a secret can be quite isolating. There are so many helpful threads on the app from other women who have been through it too," she wrote alongside the sponsored post. "It's always reassuring to know you're not alone. Whether you're already a mom, pregnant, or trying to conceive, I really recommend you join the @peanut community. It's an amazing space to build friendships, find support and learn from other women at a similar stage in life. There's nothing like support from other women to get you through."