I found a REALLY great post written by Kathryn Brightbill outlining some of the politicized ideology behind Fundamentalist Christianity, the Quiverfull movement, and the actual cults within the Quiverfull ideology.
Quiverfull is a politicized ideology based on Psalm 127 that says you should have as many children as possible because those children are arrows in the culture wars. It’s explicitly about taking over society by outbreeding the rest of the population.
Fundamentalism itself wasn’t even politicized until the rise of the Moral Majority and related groups in the late 1970s. Prior to that, most fundamentalists believed that Christians should stay out of politics. The quiverfull movement came even later and didn’t gain much foothold until the 1990s.
Bottom line? Quiverfull is a subset of the politicized fundamentalism that developed in just the last forty years.