Intended breastfeeding duration predicts infant formula use in the early postpartum period

Maternal infant-feeding intention is a strong determinant of breastfeeding initiation and duration. However, the effect of intended breastfeeding duration on infant-feeding practices has been less studied. This secondary analysis uses data collected in the CASTLE study which investigated the roles of Candida and Staphylococcus aureus in nipple and breast pain in breastfeeding women; 360 women intending to breastfeed for at least 8 weeks were recruited in late pregnancy and followed weekly for first 4 weeks postpartum. Intended breastfeeding duration was ascertained at recruitment. Method of infant feeding in previous 24 hours was collected at each time point. Women who intended to breastfeed for <= 6 months were more likely to give their babies formula during first 4 weeks postpartum: 41% (47/116) compared to 27% (59/220) of women planning to breastfeed for > 6 months, RR 1.5 (95%CI 1.1, 2.1, p=0.01). Only 38% (129/336) of women were completely breastfeeding at the breast at all time points in first 4 weeks; women intending to breastfeed for > 6 months were more likely to be completely breastfeeding at the breast at all time points: 41% (89/220) compared to 26% (30/116) (RR 1.6, 95%CI 1.1, 2.2, p=0.008). This suggests that some early formula use stems from maternal perception rather than infant requirement. Clinicians could ask all women antenatally how long they plan to breastfeed to facilitate a discussion about global recommendations for 6 months' exclusive breastfeeding and continued breastfeeding for two years and beyond.