"Don't believe everything you read, I'm definitely not pregnant!" she tells Us in a statement. "I'm on the pill. And, I'm only 20 -- I don't want to have kids until I'm out of school and we're married."
Three years ago, Lowell and her now-fiance, Tyler Baltierra, placed their daughter Carly for adoption.
In a recent chat with Us Weekly, Lowell and Baltierra, 19, admitted to Us they're still grappling with the decision, but said their relationship with Carly's adoptive parents has "gotten stronger."
In Tuesday's season premiere of "Teen Mom," the couple reunited with Carly on her second birthday. "It's one of the most emotional things on the premiere," Baltierra, 19, told Us. "She's totally different [now] -- she's walking and talking!"