The TV host told ITV's This Morning that she felt absolutely awful in the early stages, made worse because she was filming The Voice UK at the time and nobody knew.
She said: "I feel good now but I felt horrific at first."
"It was pretty bad because you know how full on the auditions are," she said. "They were such long days and the only person who knew was my make-up artist. I would be trying to get a nap at any time I could. After about 16 weeks, I got through it and now I feel alright."
Emma said she'll be eight months by the time The Voice live shows roll around, joking: "I might just make it or we may have a BBC baby!"
She and musician husband Matt Willis are already parents to daughter Isabelle and son Ace.
We can see her on The Voice this weekend and nightly on CBB