Why do girls have different breast sizes?

When we girls reach puberty, we begin to develop, and the most obvious sign of development is that our breasts begin to grow larger. But some careful girls will find that their breasts are of different sizes, which often makes them feel uncomfortable. We will unconsciously keep our eyes on our breasts of different sizes, which makes many girls very troubled. So why do girls' breasts have different sizes?

From a medical point of view, the causes of asymmetric breast development can be divided into two aspects: physiological and pathological.

Let’s talk about “physiology” first. The breasts of adolescent girls are usually different in size, which is usually caused by the different sensitivity of a substance called "milk buds" in the breasts to estrogen and progesterone in the body. The nipple bud on the more sensitive side develops first and grows faster, so it appears fuller; the nipple bud on the less sensitive side develops slowly and grows slower, so it appears smaller. Another reason is that asymmetric movements of the limbs can affect local blood circulation. For example, long-term exercise of one upper limb or chest muscle will cause the breast on one side to develop faster.

In addition, habitual sleeping posture and sleeping on one side for a long time can also cause asymmetric breast development. Another point that is easily overlooked is that when girls' breasts mature, if they do not use bras to support their breasts, the breast burden will be uneven. Because the breasts have no muscle tissue, only glandular tissue and fat, they are supported by connective tissue. This connective tissue acts like a taut mesh of fibers that provides support. However, unlike muscle tissue, it has no elasticity. Therefore, if girls do not wear bras in a timely manner during breast development, uneven breast development may occur.

Next, let’s talk about the “pathological” reasons for uneven breast development. Asymmetric breast development may also occur when one breast is congenitally underdeveloped, one breast is damaged after birth, one breast is traumatic or inflamed, or one breast has a tumor or other lesions.

There are many reasons why girls' breasts are of different sizes. It may be due to incorrect sleeping posture during the development period, or it may be congenital. Both are possible. But girls don’t need to worry too much about it. After puberty, the breast size will return to normal. But if it continues to be like this, you might as well go to the hospital to consult a doctor so that this problem can be resolved as soon as possible.