The MTV personality, 26, shared a sweet photo from her and husband Tyler Baltierra's initial pregnancy photoshoot on Instagram this week, in which she cradles her bump in a long gown and flower crown as their 4-year-old daughter, Novalee Reign, grins at the camera.
"Can't believe I'm 35 weeks tomorrow!!!!!" she captioned the photo. "Baby girl we CANT WAIT to meet, hold, and smell you!!! Nova is beyond excited to be your big sissy!!!! Daddy can't hide his excitement and momma can't wait to have you in her arms!!!!"
The couple announced they were pregnant again in September after losing a baby to miscarriage the previous year.
"The big news is that we are expecting our rainbow baby. This baby is our rainbow after the storm. I'm super excited," Lowell told Us Weekly to announce she was expecting.
"It was a huge shock at first. We were not planning it, especially after the miscarriage and how I went downhill with my mental illness," she continued. "We were going to wait a really long time. We were using protection and everything and still got pregnant. This baby just wanted to be here. It was very unexpected."
After Lowell's miscarriage, she explained on Teen Mom OG that she experienced suicidal thoughts that prompted her to seek mental health treatment away from her family. During her stay, she also addressed the trauma that resulted from her and Baltierra giving their first child, 9-year-old daughter Carly, up for adoption when she was born.
During therapy, Baltierra suggested the couple take 30 days apart as a trial separation for them to figure out their identities separately before they welcomed their third child.
Despite misgivings from their friends and family, the couple worked through their issues and returned home to one another at the end of the separation, now focusing on preparing their newly-renovated home for the baby.
They're even thinking about having another child after this one, with the pregnant mom telling a fan who asked on Instagram if they were planning on getting pregnant with baby number four that they were "definitely" going to try for a fourth.
"I think we're just gonna go right for No. 4 right after this one's born," she added. "We wanna be done before we're 30, you know?"
Teen Mom 2 airs Mondays at 9 p.m. ET on MTV.
Photo credit: MTV