Breast-feeding more than one child is called tandem breast-feeding. If you continue to feed your older child along with your newborn, keep in mind that the youngest child's feeding is the highest priority.
Some general feeding guidelines can help ensure that your newborn is properly nourished:
Early research shows that breast-feeding more than one child may harm the youngest child's growth.1 If you decide to breast-feed more than one child, make sure your newborn maintains a healthy growth pattern. Talk to your doctor about any specific questions or concerns. Be aware that the interruptions in your older child's breast-feeding routine may naturally begin the weaning process.
Citations
WebMD Medical Reference from Healthwise