Thelarche is the onset of secondary (postnatal) breast development...usually after 8 years...may occur on one side first, or both sides simultaneously. It is a result of rising levels of estradiol.
Girl 1 month old on a breastfed after pediatrician revision addressed on breast ultrasound.
On ultrasonography in subareolar area is visualized extended milk ducts and a small portion of glandular tissue. Recommended consultation of an endocrinologist.
