She was pictured in her pyjamas with the baby over her shoulder.
“At the end of the day who even needs breast pads as long as they are happy, healthy and full of love for themselves and others,” she captioned the shot that she shared on Monday 22 May.
The photo showed milk had leaked through Anderson’s grey top revealing two wet patches.
The image resonated with mums on Instagram, who praised the trainer for sharing such a “real” image of motherhood.
“This is so true, I love this post,” one mum commented. “Thanks for being so real.”
Another mum wrote: “I love this so much Tracy. It brought me back to the early days with both of my kids when it is all love and very little sleep.
“Thank you for being a woman who’s never afraid to be real.”
And one mum also wrote: “That is such a heartwarming picture. Everything about it. I remember that time too well. Nice to see you’re exactly like us.”
Anderson was sharing the photo on the day of her daughter’s fifth birthday.
“Five years ago today you doubled my mummy heart light,” she wrote on another photo of her daughter as a newborn. “I never could have imagined a light as bright as yours.”