Here’s an odd fact: among Western women, breastfeeding does not much suppress fertility, whereas among hunter-gatherers it does. In the US,on average, women start menstruating about eight weeks after giving birth whether or not they breast feed their babies, whereas among the !Kung bushmen who always breastfeed, the cycle does not resume for anything up to three years.
Part of the difference is to be explained by nourishment. The average daily calorific intake of the Bushmen women seems to be about 1100 calories. The average for modern Americans must be at least twice that. But it turns out there is another cultural difference. The Bushmen don’t expect their babies to sleep through the night, and feed them on demand, as often as eight times an hour. Western women who feed in the same style won’t menstruate for up to nine months after birth, and so aren’t fertile in that time either.
So far, I have lifted the facts from this rather thought-provoking paper (via), But there is a twist. The Puritans of New England combined extraordinarily brutal and coercive child-rearing practices with unmatched fertility. In Waltham, Massachussetts, in the 1730s, the average marriage produced 9.7 children; the Puritan emigration to New England stopped at around 21,000 in 1641, and this population produced 16 million descendants by 1988.
I can’t find an exact reference to puritan breast-feeding practices in Albion’s Seed, but it would be astonishing if the Puritans had allowed their babies to determine when they should be fed. It was certainly among their modern descendants that the idea of the four-hourly feed arose and flourished. So this regulated breast feeding would have entirely removed the contraceptive effects of lactation, and supplied another reason for the high fertility rates of the Puritans (or, as they would see it, another sign of God’s blessing).