"A feeew days late (#thirdchild) but holy MOLY did the month fly by! This little lady fits in perfectly with our family and she is SO loved," Houska captioned the image of Layne DeBoer.
Fans left adoring comments on the post, like "Omg she is a doll," and "Beautiful baby girl."
"She is adorbs!! I couldn't be happier for you and your beautiful family!" someone wrote.
Houska gave birth to her second child with husband Cole DeBoer on Aug. 29, the day of her 27th birthday.
"Happy birthday to my sweet perfect wife Chelsea DeBoer who just gave our family this beautiful blessing!" DeBoer shared on Instagram on the day his new daughter was brought into the world. "Sharing the same amazing day I am so in love with our family! Our newest edition Baby Layne!!"
The two were already parents to 1-year-old Son Watson. Houska also shares 9-year-old daughter Aubree with ex Adam Lind. Both kids have been "great" with baby Layne, Houska's father Randy Houska revealed in a new episode of his web series, Losing Randy.
"Watson loves her, Aubree loves her, they're both great with her," he said. "Watson just stands there and rubs her little head and says, 'Nice, nice,' because I'm pretty sure everyone tells him, 'Watson, be nice nice to the baby.'"
Randy gushed over the arrival of his third grandchild, saying Houska had no complications during delivery.
"It's been a pretty exciting last couple of weeks in the Houska/DeBoer family," Randy said in the video. "All went well. I believe she called me at 6 a.m. and said, 'Hey, gonna have a baby! And then they got to the hospital, and as per her usual, she delivered very quickly with no complications — everything went great."
Houska and DeBoer first announced they were expecting their second child together in March via an Instagram sonogram. They've been married for two years, as detailed in an Instagram post Houska shared on Monday celebrating their anniversary.0comments
"Two years. Two babies AND one pretty amazing 9 year old. I love life with you, babe," Houska captioned a photo of the two of them dancing at their wedding reception. "Thank you for giving me the life I always dreamed about. happy anniversary @coledeboer !!"
Season 8 of Teen Mom 2 aired its finale in August but will likely return for a ninth season in 2019.