It is rare and affects about 1 child in every 10,000 in the United States. The same hormone changes that cause puberty also cause precocious puberty. Premature stimulation of the endocrine system releases hormones from the pituitary gland. These hormones stimulate the ovaries to make sex hormones. The sex hormones, including estrogen, cause sexual maturation in girls.
Sex hormones accelerate growth as well as the skeletal process that ends growth.
Girls who start puberty prematurely are tall for their age, but growth stops earlier for them. Their full height potential as adults is never achieved. They often grow no taller than 5 feet. Behavior changes during premature puberty include moodiness and irritability similar to teenage girls. They may become too self-conscious with their physical changes to undress in front of others, including parents.