Atwood based it on Islam, Communist China and Romania, Quakers and Puritans of the 1600’s.
https://www.nytimes.com/1990/04/14/movies/margaret-atwood-reflects-on-a-hit.html
Even assuming the Quaker and Puritan facets of the basis are well founded (I say they are not), the other sources are much more current and relevant, especially that of the Religion of PeeCee.