Using data from the Cebu Longitudinal Health and Nutrition Survey, this paper attempts to disentangle the complex interrelationship among breastfeeding, postpartum amenorrhea, and contraceptive method choice. Three different hypotheses have been suggested as possible causes
for an observed inverse relationship between breastfeeding and contraceptive use. First, because breastfeeding delays the resumption of menses, an inverse relationship would be observed if couples delay adoption of a contraception until menses resumes. Second, if women are forward thinking, they might actually breastfeed, in part, to delay the resumption of menses, thereby substituting breastfeeding for contraception. Lastly, the observed inverse relationship may be caused by endogeneity bias. This study finds evidence that women do substitute breastfeeding for contraception but that endogeneity bias must be controlled to avoid overstating the relationship. Additionally, the
results suggest that although increased education and income result in decreased breastfeeding, the resulting fertility impact will be offset by changes in contraceptive use.
