The Teen Mom star confirmed her exciting news to In Touch magazine, admitting that she and long term partner Taylor McKinney are overjoyed.
Maci revealed that her pregnancy was a very unexpected surprise, given that doctors previously told her that the chances of conceiving again were low due to her polycystic ovary syndrome diagnosis.
"We still can't believe it. It was a huge shock but we are very excited," she said.
Maci, who is already mum to five-year-old Bentley, added: "I didn’t think that another pregnancy was possible."
Maci first came onto our TV screens as a cast member of reality show 16 and Pregnant, which followed her journey through her pregnancy with Bentley.
She went on to star in a further four series of Teen Mom, which documented her journey through motherhood, and how she juggled life, college and relationships while raising her son.
Congratulations to Maci on her wonderful news.
