Breast development in girls. Or is this just normal, this continuely happens? Health Professionals. While there is no specific law within Britain around breast ironing or flattening, the FGM center states that it is a clear form of physical abuse. During pregnancy, your breasts will begin getting ready to produce milk for your baby, which is called lactation. I am Survivor. I haven't gained significant weight, so I'm just confused as to why my breasts seem to have suddenly developed a bit more, after all these years of being one size that I was perfectly happy with! Adult in size. It sounds your breasts are normal.