Large breasts can be caused by genetic factors, changes in hormone levels, obesity, breast diseases, the influence of medications, and other factors.

1. Genetic factors: Genetics plays an important role in breast size. If women in the family generally have larger breasts, then the probability of offspring women having larger breasts will also be relatively high. This is because genes affect the development of breast tissue and the distribution of fat, laying the foundation for breast growth from the embryonic stage.

2. Changes in hormone levels: During puberty, the levels of estrogen and progesterone in the female body rise, which stimulates the development of milk ducts and acinar, and promotes the gradual enlargement of the breasts. During pregnancy and lactation, hormone levels change significantly again, the breast tissue proliferates further in preparation for breastfeeding, and the breasts become significantly larger. In addition, some endocrine diseases, such as ovarian tumors, pituitary tumors, etc., may cause abnormal hormone secretion in the body, causing excessive breast development.

3. Obesity: When the amount of body fat increases, the fat tissue in the breasts also increases, making the breasts appear larger. Obese people have a wide range of fat distribution as a whole, and the breasts, as one of the fat-rich parts, will be significantly affected. Unreasonable eating habits, such as long-term high-calorie, high-fat diet, lack of exercise, etc., can lead to obesity, which in turn can make the breasts enlarged.

4. Breast disease: Certain breast diseases can also cause breast enlargement. For example, breast fibroids, which are common benign tumors of the breast, grow and cause local breast tissue to bulge, resulting in a larger appearance of the chest. Breast hyperplasia may also cause swelling and enlargement of the breasts, which are often felt painful or tingling in the chest, which may worsen around the time of the menstrual cycle. Breast cancer, although relatively rare, can cause abnormal enlargements or lumps in the chest.

5. Drug Effects: Long-term use of certain medications may affect hormone levels in the body, which can lead to enlarged breasts. If birth control pills contain estrogen and progesterone, long-term use may cause chest pain and enlargement. Some medications for psychiatric disorders, such as antidepressants, antipsychotics, etc., may also have side effects that cause breast enlargement. In addition, certain growth-promoting medications, if used incorrectly, may also have an effect on breast development.

A larger chest is the result of a combination of factors. Genetic factors are congenital and difficult to change; Factors such as changes in hormone levels, obesity, breast diseases, and the effects of medications can be improved or controlled through lifestyle modifications, treatment of diseases, or rational use of medications. If the chest suddenly enlarges or is accompanied by abnormal symptoms such as pain and lumps, you should go to the breast surgery department of a regular hospital in time for detailed examination and diagnosis, so that corresponding treatment measures can be taken.

This article is only for health science popularization and does not constitute medication or medical guidelines, it is recommended to seek medical attention in time if you have health problems.