Effects of breast milk on pain severity during muscular injection of hepatitis B vaccine in neonates in a teaching hospital in Iran.

The results of this study showed that breastfeeding decreases pain severity during painful experiences in neonates, which is in accordance with other reports. Based on this finding, neonates are advised to be breastfed if a painful intervention such as vaccination is needed. The pain-relieving effect of breast milk could also be added to its other suitable effects.