Mrs Edwards, a lawyer and author, died yesterday at the age of 61 after a six-year battle with cancer.
She was a supporter of gay rights and in 2008, while her husband was running for the presidency, declared that she believed in legalising gay marriage.
While Mr Edwards reserved his support for civil unions, she told reporters: “I don’t know why somebody else’s marriage has anything to do with me. I’m completely comfortable with gay marriage.”
The Westboro Baptist Church, which usually targets the funerals of killed soldiers with the slogan ‘God Hates Fags’, said it would be outside the Edenton Street United Methodist Church in Raleigh, North Carolina, on Saturday.
The church, which claims that soldier deaths abroad are God’s vengeance for gay rights, released a statement condemning her for having fertility treatment and for questioning her faith after her 16-year-old son Wade was killed in an accident.
In a final message posted on her Facebook page, Mrs Edwards avoided any mention of God and instead cited her “faith in the power of resilience and hope”.