Breast-milk and infant nutrition study

The primary exposure of interest is the blood folic acid concentration and blood folate status of the mother. The study aims to observe the effect of maternal blood folate status on milk folate-binding protein concentration and on infant blood folate status. Blood folic acid status and blood total folate status of the mother are assessed at 8 weeks postpartum (the folate status of the mother will be conditional on the previous folate and folic acid intake, most likely over the course of the pregnancy as steady state concentrations are only reached after 40 or more weeks). Folate-binding protein concentration and total folate in breast-milk at 8 weeks postpartum is also measured as an exposure variable in relation to infant folate status.