From the Guidelines
Puberty in females is considered to begin with breast development (thelarche) before the age of 8 years, which is defined as precocious puberty (PP) 1. The first physical sign of puberty in girls is breast development, also known as thelarche, which can occur as early as before age 8 years 1. Some key points to consider when evaluating puberty in females include:
- The timing of thelarche can vary with ethnicity and may be accelerating among US girls 1
- Adrenarche, or the growth of pubic or axillary hair, is not a sign of activation of the hypothalamic-pituitary-gonadal (HPG) axis in girls 1
- Tanner stage 2 breast development before 8 years of age is a reasonable definition of precocious puberty 1 The activation of the HPG axis leads to the release of hormones such as LH and FSH, which in turn stimulate the growth and development of the reproductive system 1. It is essential to note that the definition of puberty in females is based on physical and hormonal changes, and breast development before the age of 8 years is considered a key indicator of precocious puberty 1.
From the Research
Definition of Puberty in Females
Puberty in females can be divided into two independent events: adrenarche and gonadarche 2. Adrenarche refers to the maturation of the adrenal glands, resulting in the production of androgens, while gonadarche refers to the maturation of the ovaries, resulting in the production of estrogen.
Stages of Puberty
The stages of puberty in females include:
- Thelarche: the development of breast buds, which is usually the first sign of puberty 3, 4
- Pubarche: the development of pubic hair, which can occur before or after thelarche 2, 5
- Menarche: the first menstrual period, which usually occurs after thelarche and pubarche 3, 5
Age of Puberty Onset
The age of puberty onset in females can vary, but on average:
- Thelarche occurs around 9.7 years of age 3
- Pubarche occurs around 10-12 years of age 5
- Menarche occurs around 12.8 years of age 3
Factors Influencing Puberty
Several factors can influence the onset and progression of puberty in females, including:
- Ethnicity: African-American girls tend to enter puberty earlier than Caucasian girls 3, 5
- Diabetes: girls with type 1 diabetes may experience delayed puberty and ovarian function abnormalities 6
- Hormonal imbalances: hormonal imbalances, such as those caused by Turner syndrome, can affect puberty onset and progression 2