Thelarche

[1][6] Moreover, puberty is considered delayed if breast development does not start at age 13 or if a female has not had her first period (menarche) within three years of thelarche.

[7] Additionally, secondary breast development occurring before the age of 7 years could be a sign of premature thelarche or precocious puberty.

[14] Premature thelarche is a benign condition in which a young female has breast development before age eight without any accompanied pubertal changes.

[15] Initial breast development can be bilateral or unilateral and usually begins with a firm, disc-like area of tissue under the areola, which can be mistaken for a mass but is almost always a normal physiologic process.

[4][15] Moreover, in 90% of patients with isolated premature thelarche, breast enlargement will resolve six months to 6 years after diagnosis.

[7][17] The breasts of these females typically exhibit alternating progression and regression patterns of growth in 6-week intervals, often completely decreasing in size within 1.5 years.

[18] However, premature thelarche should be evaluated to rule out additional causes, such as hypothyroidism or precocious puberty, especially if other symptoms are present.

[1][4][5] Precocious puberty can be identified using a pelvic ultrasound to assess the size of ovaries and uterus relative to the individual's age.

[5] Other methods of diagnosis consist of blood tests to determine hormone levels and simple physician assessments with follow-up appointments to track the progression of development.