Increase in natural fertility during the early stages of modernization: Canadian Indians case study.

It has been hypothesized that populations may experience an increase in their natural fertility during the early stages of modernization as a result of the relaxation of various fertility-inhibiting practices and customs prevalent in traditional societies. This article offers evidence of such an increase in natural fertility among Canadian Indians. The main underlying cause is found to be in the massive, almost abrupt, shift from prolonged breastfeeding to bottlefeeding ;which took place prior to the onset of large-scale birth control practices among Canadian Indians.