Evans went to hospital in April after a severe allergic reaction to antibiotics that she was taking for the flu.
She then experienced constant seizures and was placed in a medically induced coma.
On 30th April, she was starting to be weaned off coma medication for fear of the risks of being comatose for too long and the seizures continued at a reduced rate.
On Thursday, staff found she had swelling on her brain and on Saturday morning she died in hospital.
Rachel Held Evans was most well-know for her book A Year of Biblical Womanhood and her popular blog where she wrote about topics such as patriarchy, evangelical culture, Donald Trump, welcoming young people into church and parenting.
She spoke at festivals and recently released her new book Inspired that aims to 'avoid noncommittal liberalism on one hand and strident literalism on the other', according to her website.
Many fans followed updates from her husband Dan Evans and used the hashtag #PrayForRHE on Twitter.
Dan Evans wrote on Saturday: "This entire experience is surreal. I keep hoping it's a nightmare from which I'll awake. I feel like I'm telling someone else's story.
"I cannot express how much the support means to me and our kids. To everyone who has prayed, called, texted, driven, flown, given of themselves physically and financially to help ease this burden: Thank you. We are privileged. Rachel's presence in this world was a gift to us all and her work will long survive her."
Nearly 4,000 people donated to her medical costs, with the total so far being $170,000.
Supporters of her work have been praising how she lived her life; challenging sterotypical gender roles, calling out politicians who were trying to tap into the evangelical vote, and giving a voice to those who had a faith but weren't sure about the moral culture they had grown up with.
Pastor and author Tim Keller wrote: "Kathy and I began praying for her as soon as we heard about her illness. We grieve so much for her family who has lost wife and mother."
The hip hop artist Lecrae wrote: "Prayers to the family of @rachelheldevans didn't really know her but she used her voice to support me when others wouldn't. Welcome home."
Prayers to the family of @rachelheldevans didn't really know her but she used her voice to support me when others wouldn't. Welcome home.
— Lecrae (@lecrae) May 4, 2019
I spent more than a year reporting on fundamentalist christianity and I cannot tell you how many of the people negatively impacted by their experiences in that community found such strength in Rachel Held Evans' writings. This is an incalculable loss. https://t.co/WUQ9DFC38q
— Jessica Huseman (@JessicaHuseman) May 4, 2019
Rachel Held Evans had two young children.
In her last blog post, she wrote: "Death is a part of life.
"My prayer for you this season is that you make time to celebrate that reality, and to grieve that reality, and that you will know you are not alone."
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