Is breast-feeding a substitute for contraception in family planning?

Using data from the Cebu Longitudinal Health and Nutrition Survey, I disentangle the complex interrelationship between breast-feeding, postpartum amenorrhea, and choice of contraceptive method. I find evidence that women substitute breast-feeding for contraception. Further, endogeneity bias, if not controlled, would cause the relationship to be slightly overstated. In addition, the results suggest that although increased education and income result in decreased breast-feeding, any effect on fertility will be offset by changes in contraceptive use.