See Teen Mom star Mackenzie Douthit's "last picture" of her big baby bump before giving birth to her second child, a girl. Credit: Courtesy Mackenzie Douthit

Goodbye, bump. Hello, baby! Mackenzie McKee (nee Douthit) shared a photo of her huge baby bump on Instagram Thursday, Feb. 6, shortly before giving birth to her second child, a baby girl.

"Last picture," she captioned the photo. "37 weeks." In the snapshot, the 19-year-old Teen Mom 3 star lifts up her T-shirt to reveal her pregnant belly. She is standing in a hospital room, preparing to give birth.

Earlier that same day, the reality TV star shared a video on Instagram of husband Josh McKee playing guitar. "Last day of being pregnant = a nice hot bath and Josh playing me some music," the Miami, Okla. native wrote, before heading to the hospital. (Mackenzie didn't specify if she had a scheduled birth.)

The high school sweethearts, who wed in August 2013, are already parents to son Gannon, 2. They revealed they were expecting a baby girl in a Vine video back in September.

As of Friday morning, Mackenzie had yet to share another update on her pregnancy and impending arrival of her daughter.