Breast 4a is possible to wear Mannix as there is not much relationship between the two. Breast 4a is mainly caused by estrogen, and the Mannuelle ring releases progesterone. The Mannuelle IUD mainly releases progesterone periodically, which is used to inhibit the proliferative response of the uterine lining, but the Mannuelle IUD contains less hormone, so it will not have an effect on breast 4a. The root cause of breast 4a is the disturbance of the ratio of estrogen and progesterone, which leads to excessive proliferation and incomplete restoration of the mammary glands, in which the proliferation of the mammary glands is the role of estrogen, while the secretion and restoration is mainly the role of progesterone. The Mannix ring is not going to have an effect on breast hyperplasia, so breast 4a patients can wear Mannix.