A pastor's wife and author who wrote an open letter to right-to-die campaigner Brittany Maynard has died after a three-year battle with breast cancer.

Kara Tippetts, 38, was diagnosed with stage four cancer in 2012 and died on Sunday. Last year, she wrote to Maynard urging her to reconsider ending her life. Maynard had a brain tumour and campaigned extensively for dignity in dying, becoming the face of Compassion & Choices. She died by assisted suicide in November.

Tippetts wrote in October, before Maynard's death: "Dear heart, we simply disagree. Suffering is not the absence of goodness, it is not the absence of beauty, but perhaps it can be the place where true beauty can be known.

"In your choosing your own death, you are robbing those that love you with the such tenderness, the opportunity of meeting you in your last moments and extending you love in your last breaths... That last kiss, that last warm touch, that last breath, matters — but it was never intended for us to decide when that last breath is breathed."

A post on Tippett's blog, named Mundane Faithfulness, says that Kara embraced her situation with courage, and never gave up on her faith."She believed that cancer was not the point, but Jesus was; how she responded and trusted Christ in the midst of this hard was where she would find Grace."

"Knowing Jesus, knowing that He understands my hard goodbye, He walks with me in my dying. My heart longs for you to know Him in your dying. Because in His dying, He protected my living. My living beyond this place," Tippett told Maynard.

"Brittany, when we trust Jesus to be the carrier, protector, redeemer of our hearts, death is no longer dying. My heart longs for you to know this truth, this love, this forever living."

Tippett recently wrote that treatment was no longer helping the cancer. "My little body has grown tired of battle," she said.

"But what I see, what I know, what I have is Jesus. He has still given me breath, and with it I pray I would live well and fade well. By degrees doing both, living and dying, as I have moments left to live. I get to draw my people close, kiss them and tenderly speak love over their lives.

"I get to pray into eternity my hopes and fears for the moments of my loves. I get to laugh and cry and wonder over Heaven. I do not feel like I have the courage for this journey, but I have Jesus—and He will provide. He has given me so much to be grateful for, and that gratitude, that wondering over His love, will cover us all. And it will carry us—carry us in ways we cannot comprehend."

Tippett leaves behind her husband, Jason, and four children.