Frankie, who is one fifth of The Saturdays, is expecting her second child with footballer husband Wayne Bridge in August. The couple are already parents to 19-month-old son Parker.
Speaking to The Mirror, she said: "Women should be honest about the fact that although having a baby is wonderful, it can be hard. It's a massive body change and life change and comes with a whole wave of emotions.
"Just because I'm in the public eye it doesn't mean I escape any of that and after I've had this baby, I won't just snap back into shape by magic."
She added: "It'll take time because my priority won't be my weight, it'll be the baby and my son and helping them bond. I think that's the healthy reality for the majority of women."
Frankie announced her pregnancy early in January, as she was forced to pull out of Strictly Come Dancing's live tour after suffering with severe morning sickness.
Frankie suffered hyperemesis gravidarum, the condition that Kate Middleton has also suffered from, which causes extreme nausea and vomiting.
"I'm feeling so much better but it hasn't been an easy pregnancy," Frankie told the newspaper. "The condition kicked in at around six weeks and I was so ill they wanted to admit me to hospital. The only reason I didn't go is I couldn't bear the thought of the car journey.
"I was terribly upset at not being able to tour with Strictly although at least, thanks to Kate Middleton, everyone understood what I was suffering from."
For exclusive competitions and amazing prizes visit Reveal's Facebook page NOW!
Best celeb maternity wear: