Research has shown that breast-feeding doesn't negatively affect breast shape or volume.
During pregnancy, the ligaments that support your breasts might stretch as your breasts get fuller and heavier. This stretching might contribute to sagging breasts after pregnancy — whether or not you breast-feed your baby. Sagging breasts might be more noticeable with each subsequent pregnancy.
Other factors also contribute to sagging breasts, including aging and smoking — both of which reduce skin elasticity. Being overweight, losing a significant amount of weight and having large breasts can have a similar effect.
Don't let a fear of sagging breasts stop you from breast-feeding. To help maintain the appearance of your breasts at any stage of life, make healthy lifestyle choices. Include regular physical activity in your daily routine and maintain a healthy weight. Eat a healthy diet. If you smoke, ask your doctor to help you quit.