Catelynn Lowell posted a sonogram Saturday amid her latest pregnancy.
"Already can't wait to meet you little nugget," she captioned the picture.
Lowell and Baltierra placed their first child, daughter Carly, for adoption in 2009, and are parents to 3-year-old daughter NovaLee.
The couple confirmed Lowell's pregnancy this month following a miscarriage in 2017.
"It was a huge shock at first," she said. "We were not planning it, especially after the miscarriage and how I went downhill with my mental illness."
Lowell sought treatment for mental health issues in January in the wake of her miscarriage.
"Just, you know, therapy, being a mom, getting back in the swing of things, sort of."
"I feel way better. I did a whole med switch. I did genetic testing and found out that the medication I was on for five years doesn't even work for me," she shared.
"So they put me on different medications and they seem to be working really well."
Lowell came to fame on the MTV series "16 & Pregnant" before starring on "Teen Mom."
The series co-stars Maci Bookout, Amber Portwood, Cheyenne Floyd and Bristol Palin.