The singer, who is expecting her first child with fiance Eric Johnson in the coming weeks, has sported a sizeable bump throughout her pregnancy, and the extra weight has caused many to speculate about the way she looks.
However, Dr Robyn Silverman, a body expert says the scrutiny is unfair as Simpson is setting a good example to women across the globe.
"I find it appalling that people believe it is their place to criticise a woman for gaining weight during pregnancy. Jessica Simpson's body health and the health of her developing baby are the business of her doctor, her husband, and most of all, herself," Dr Silverman said.
"Jessica Simpson is a great demonstration of a woman who is enjoying her pregnancy and is not hyper focused on how she looks while pregnant."
Simpson's fluctuating weight has previously been the source of much speculation. The star recently revealed she is looking forward to getting back to her regular size.
"I had a great pregnancy. Eating and not having to worry too much about it has been fun," she said. "Taking a break from working out has definitely been fun. But I'm ready for it to be over. I'm ready to have my body back!"
Simpson recently showed off her naked pregnant figure on the front cover of Elle magazine.