Bipedalism, metabolism, and gestational development
This is interesting! And annoying, since I've been telling people about the bipedalism/pelvis size theory for years, and I don't like the thought of having been misleading. But it's mostly really interesting!
I know someone who has delivered consistently "early" with all her kids. They have been small, but she's small too. There is, of course, the danger of fitting the evidence to the situation after the fact, but this apparent oddity in her gestation length might make sense in light of this theory.
I'm assuming - not having seen it explained in the article - that a slower metabolism would lead to larger babies, because more energy would be "available" rather than used immediately for the upkeep of the mother's body. This would seem, at least superficially, to match real-world outcomes of larger mothers having larger babies. But I'm no biologist, not an I am obstetric specialist. Am I way off-base here? Does anyone have further information about this, or know of follow-up research (since I see this article is from 2012)?