Months after the couple mourned a miscarriage, the parents are reportedly expecting their third child, Lowell told Us Weekly on Thursday.
"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 the magazine after teasing a big announcement on her Instagram profile.
"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."
Some fans had anticipated the announcement of the rainbow baby, as Lowell has been teasing "big news" on social media for the past few weeks. In August, she posted on her Instagram in colorful rainbow text, "Can't wait to share our big news with y'all!" Fans took to the comments section, with many assuming she was expecting again after her miscarriage.
Lowell, 26, and Baltierra, 26, are already parents to 3-year-old daughter, Novalee. They placed their oldest daughter, Carly, who is now 9 years old, for adoption in 2009, as documented on the MTV series.
The couple, who tied the knot in August 2015, announced a pregnancy on a January episode of Teen Mom OG, later revealing during a February episode that Lowell had a miscarriage. Lowell entered a rehabilitation treatment in January after the miscarriage because she was having suicidal thoughts; she had previously completed a stint in rehab after battling postpartum depression after Novalee's birth in 2015.
The couple has been open about both of their struggles with depression and how it has affected their marriage. During an appearance on a July episode of The Dr. Oz Show, Lowell responded to a cryptic tweet from Baltierra that made headlines in May.
Dr. Oz quoted Baltierra's tweet, saying "'Laying in bed next to my peacefully sleeping wife. I can hear my daughter snoozing away through the monitor in her room. My dog is cuddled up on the floor next to me.' It sounds so beautiful, picturesque. And then you go on to say, 'and yet I feel so empty... so alone," Dr. Oz said.
Lowell said at first she thought she had done something wrong, but then realized that the tweet had nothing to do with her.
"Well I woke up in the morning and I was hanging out with Nova and he was sleeping. Then, I read it on Twitter and instantly my first reaction goes to my trauma of like 'What did I do?'" the MTV star explained. "Then, I was like no. I talk to myself, that's my trauma stuff. And then I'm automatically like it has nothing to do with you, just go in there and ask, "Is there anything I can do for you? Is there anything you need?'"
In a July Instagram post celebrating 13 years with Lowell, Baltierra gushed over his wife and their relationship.
"Life is really simple if you think about it. If you love something... fight for it. Sacrifice for it. Love it so much that it makes you want to love yourself in a way you never knew you were even capable of loving," he wrote.
"It's been 13 years together & that's not because of luck or us not arguing or not getting upset with one another... that's because everyday, we choose to love each other unconditionally, with all the flaws & all the baggage our past lives has given us," he continued.
"We choose to listen to one another & be heard by one another. We choose to confront our issues head on & fix them together. We choose to nurture our spiritual bond together & share lives ups & downs with one another," he shared. "We are lovers in this life, so we can be soulmates in our afterlife."