Dilated echogenic breast ducts 2.9mm may be caused by periductal inflammation, hormonal stimulation and intraductal papilloma. 1. Periductal inflammation: periductal inflammation is a common clinical non-lactation inflammation, the specific etiology is not clear, it is mainly seen in young women, the local skin of the breast will be warm, ultrasound can be observed under the expansion of the ducts, usually pay attention to avoid spicy and stimulating food, magnesium sulfate wet compresses. 2. Hormonal stimulation: during lactation, estrogen and progesterone will change in women’s body, so the ducts will also be affected by hormonal changes, which can be seen under ultrasound expansion, in this case, you can first observe, and after lactation, ductal expansion can be restored. 3. Intraductal papilloma: Breast ductal papilloma will stimulate the glandular epithelium to secrete fluid, and the duct will be blocked by the tumor, and the end of the duct will be dilated as a result. In this case, we can adjust the emotion first, and remove the tumor through surgery if necessary. If you find dilated breast ducts, it is recommended to make a clear diagnosis in regular hospitals and give different treatments according to different causes to avoid disease progression.