"I'm limping around. I'm still trying to figure out what [pregnancy] has done to my body, how it's changed it. What's temporary and what's permanent," Panettiere said. "I feel like an 80-year-old woman trying to go down the stairs... [and] I know some things will never be the same again."
In July, Panettiere announced that she and fiance Wladimir Klitschko were expecting their first child.
While Panettiere said she worries about her post-pregnancy physique, she also explained how being a new mother is an "out of body" experience.
"You're suddenly looking at this little thing like, 'Oh, that was you in my belly this whole time,'" Panettiere said, adding that she and Klitschko are "just getting to know her."
"She's really so sweet," Paniettiere gushed. "I'm sure that's the way it's meant to be, because when they are putting you through the ringer you're like, 'You are so lucky you're cute!'"
Panettiere and Klitschko, a Ukrainian professional boxer, announced their engagement in October 2013 after dating on and off since 2010. Panettiere has been spotted ring-side at a number of Klitschko's high-profile fights.