It is inevitable to see some changes in your breast once you are pregnant. According to this article (http://www.momjunction.com/articles/ways-to-prevent-breast-sagging-post-pregnancy_00121079/), a mother’s breast will start to sag once she is pregnant (and not because of breastfeeding per say). Factors such as the shape and size of the breasts (pre-pregnancy), percentage of fat in body, age, and smoking habits all play a part to the changes. When one is pregnant, her breasts become fuller and heavier, stretching the ligaments that support the breasts. This stretching is what that would cause the breast to sag post-pregnancy. Here are some tips to prevent the sagging: - Wear a bra that offers good support: find one that is of the right fit. Go for wider straps and one that has a support band. - Try not to gain excess weight during your pregnancy: consult your doctor to ensure that you are gaining enough but not too much. - Exercise: with permission from your doctor, keep to a simple exercise regime. Walking, yoga, swimming are good options. - Moisturize: moisturize the skin around your breast. - Go slow while losing weight after delivery: losing weight slowly and steadily may allow your skin time to adapt to the changes.
I think it varies with different women -- depending on your original body shape before pregnancy and breastfeeding. I notice that my friends who are fit before pregnancy remain "perky" even after the changes to their body. This is also because of their strict exercise and diet regime after confinement. They also take extra steps with caring for their breasts during and after pregnancy through using moisturisers, creams and wearing brassieres that give ample and good support.
From my understanding, your breast will not sag after breastfeeding. Usually, it is during pregnancy that causes your ligament to stretch thus making it sag. Sad to say but sagging of the breast is a natural process that happens with age wherein the breasts lose their suppleness and elasticity.