Marissa Fearon, 27, from Canada, shared a transformation photo, showing how her body has changed but her stomach has stayed the same.
And that's okay.
"33 weeks separate these photos, eight months of sweating, cursing, jumping, squatting, lunging, stepping, pressing and just moving in general," she wrote on Instagram.
"I am a different person now, I am stronger, I am healthier, I am happier for my kids, I am embracing my imperfections."
Fearon, who shares her fitness journey on Instagram under 'Babies And Pushups' said it took her a long time to realise her stomach wouldn't be the same after giving birth to three kids.
"Realising that my stomach will never look like some of the girls that inspired me to start training has probably been the hardest part of this journey," she wrote on another selfie of her stomach.
"I still struggle with the fact that after three kids in four years it will never ever look the way sometimes I wish it would. I will always have loose skin.
"It will probably always be a 10 shades lighter because even though I am more comfortable in my own skin than I ever have been, I still get self conscious baring it for the world to see.
"It will always be marked.
"But it bares the marks of my sweet babies. My sweet babies that grew inside of it.
"I am proud of this stomach, even if it less than perfect. Perfect is boring anyways."
Those who follow Fearon's journey have called her an inspiration for mums.
"You truly are an inspiration Marissa," one mother wrote. "I had my second child in two years this week and I'm following your journey to encourage me to do the same."
Another commented: "You seriously look fabulous, thank you for motivating me to get off my arse and be proud of my body."