The former Liberty X star is currently expecting her first child with husband Hugh Hanley. Speaking to Closer magazine, Heaton said that it had been "really hard to let my body go after being in firm control for three years".
"I'm getting used to my fuller figure. It feels strange to be posing in sexy lingerie as Eva Herzigova because, since I've been pregnant, I've become used to fishing out five-year-old knickers from the bottom of my underwear drawer," she joked. "But I love it - I'll definitely be sticking this shot in the family album to show our kids!
"I went through a period four months into the pregnancy when I felt really uncomfortable in my own skin and would cry about petty things. Hugh's been an amazing support, but he'd bring home my favourite cakes every day, which didn't help my body insecurities."
She continued: "One night, he brought home a slice of carrot cake and I screamed: 'Why are you trying to make me f**king fat?!' while stuffing it into my mouth. I was a crazy, hormonal bitch!
"I've always had problems with my weight - I've been on every diet under the sun and I've even taken diet pills in the past. Not being able to get my jeans past my thighs at four months pregnant was excruciating, but now I feel more womanly than ever. I feel maternal and, when the baby moves, I get a real sense of achievement rather than getting hung up about my weight."
She also confirmed that she plans to continue using Botox, explaining: "I can't wait to have the baby so I can have it again. I have a big frown line in the middle of my forehead and I'm conscious it's come back. I look angry all the time and it really upsets me!"
The full interview and shoot appears in the new issue of Closer, out now.
> Michelle Heaton discovers sex of unborn baby: 'There were lots of tears'