When your daughter reaches puberty, she begins to experience various physical and psychological changes. We often receive various questions about the pubertal development of girls, so let’s learn together and be a good mother who accompanies her growth. Li Ying, Department of Endocrinology, Shanghai Tongji Hospital
First of all, what is puberty?
Simply put, it is the stage of transition from a child’s sexual infancy to a sexually mature adult. During this process, a series of complex and interacting sequential processes of physical, somatic and psychological changes occur in the body. After this period, she turns from a child into an “adult”!
What are the changes in the body during puberty?
The main physiological changes that occur during adolescence include
(1) Emergence of gonadal function (gonadarche): Stimulated by pituitary follicle-stimulating hormone and luteinizing hormone, gonadal function begins to activate. The girl’s ovaries produce estrogen, which causes breast development and bone growth. In late puberty, menstruation and ovulation occur, and estrogen induces skeletal maturation, fusion of growth plates, and termination of linear growth in late puberty. In short, it is at this point that gonadal hormones begin to be produced and come into play under the action of the pituitary gland (the endocrine commander)!
(2) Adrenal primordial function (adrenarche): Physical changes triggered by the production of androgens by the adrenal cortex (an important organ of the endocrine system). These include the growth of pubic and axillary hair, the maturation of sweat glands (producing adult body odor), and acne. In short, another endocrine organ, the adrenal gland, begins to synthesize androgens, and changes in the body (mainly in hair and skin) follow.
Through these two physiological changes, the body undergoes five major changes, each of which is dynamic and sequential.
(1) Activation of the neuroendocrine system, leading to the release of GnRH-GnH (gonadotropin-releasing hormone – gonadotropin)
(2) Emergence, development and maturation of secondary sexual characteristics
(3) Growth spurt (growth spurt) until epiphyseal closure and cessation of height growth
(4) Differentiation and development of reproductive organs and gametes to maturity, with mature reproductive function
(5) Mental and psychological maturity
The normalcy of puberty is assessed by the dynamics of these five major characteristics. Among them, accelerated growth in height and the appearance and development of secondary sexual characteristics are clearly visible and important changes.
The course of pubertal development in girls
The pubertal development of girls can be divided into three stages: in the early stages, accelerated height growth predominates; in the middle stages, the development of secondary sexual characteristics predominates; and over time, accelerated height growth terminates and the reproductive organs develop and mature.
When does puberty start?
When puberty starts varies from person to person, and this is related to genetics, environment, and nutrition. Of these, genetics is the most obvious factor, with girls’ puberty usually initiating at about the same time as their mothers’ puberty.
Girls typically begin puberty between the ages of 9 and 12.
Boys reach puberty later than girls, typically at 10-13 years of age.
Typical changes during puberty
What are the typical changes in a child’s body during puberty, mainly height spikes and the development of secondary sexual characteristics? Let’s take a look at these two possible changes in your child!
The first aspect: height increase!
How much does height generally grow during puberty?
Statistics show that puberty can contribute 17% to 18% of height, and if the final height is 160 cm, this period contributes almost 30 cm of height.
When do you grow the fastest?
Girls’ growth spurt will occur two years earlier than boys.
Sequence of pubertal development in girls
This graph (US) shows the rate of pubertal growth and the sequence of pubertal development in girls. The horizontal axis is age and the vertical axis is growth rate (how many centimeters per year). Once a child enters puberty, the rate of height growth increases from an average of 5-6 cm per year (range 3-8 cm, varies from person to person) in childhood to a peak of 8-9 cm per year by the end of puberty, when the epiphysis basically closes and growth largely stops.
The peak growth rate for girls generally occurs six months before the first menstrual period, and the growth surge period is usually 2 years. Boys have a height surge period 2 years later than girls, so they have two more years of prepubertal height gain than girls (3-8 cm per year), and boys have a higher peak growth rate than girls (boys average 10.3 cm; girls average 9 cm).
Height growth is seen throughout the year, with seasonal differences, and most children grow faster in the spring.
In addition, both the trunk and the limbs grow during puberty, but the accelerated growth of the limbs precedes the trunk and the distal end precedes the proximal end, so adolescents have the impression of “long arms and legs”. In late adolescence, the growth of the torso is more obvious.
The second aspect: the development of secondary sexual characteristics
What are secondary sexual characteristics?
Secondary sexual characteristics are characteristics that are not reproductive organs but can be used to distinguish the sex of a species.
The secondary sexual characteristics of females are well-developed mammary glands, a wide pelvis, abundant subcutaneous fat, and a shrill voice.
What is the order of development of secondary sexual characteristics in females?
The order of development of secondary sexual characteristics in girls
In a survey conducted by the Chinese Journal of Endocrinology and Metabolism in 2010 on the development of secondary sexual characteristics and menarche of girls in nine major cities in China (the most recent data available), the median (50%) age was
Tanner II stage of breast development was 9.2 years
The median age of pubic hair development is 11.16 years
The median age of menarche is 12.27 years
The sequence of pubertal development in today’s Chinese girls starts with breast development, followed by pubic hair development and menarche about 2 and 3 years later, respectively.
The specific data for urban girls are here, so you can probably compare them (all units are “years”; Pn means percentile).
Major percentile ages of secondary sexual characteristics development and menarche for girls in nine major cities in China
What are the stages of breast development?
Assessing breast development is internationally accepted – Tanner staging
Stage I Prepubertal breasts, with only slightly protruding nipples
Stage II Breast bud stage. The breast bulges like a mound, the nucleus can be seen within the areola, and the areola increases
Stage III: Further growth of the breast and areola and areola coloring.
Stage IV The breast and areola are elevated and the areola rises above the breast to form a second mound. This phase is brief and may or may not occur
Stage V Maturation. The protruding areola grows flat, the breast grows further, and the nipple grows to maturity.
It takes an average of four years to go from stage II to stage V. Stage II can last from six months to two years, and stage V usually follows the first menstrual period.
What are the stages of pubic hair development?
Stage I No pubic hair. (There may be hair in the pubic region, like the hair on the forearm)
Stage II The appearance of sparse, straight, thin, unpigmented or light brown pubic hairs
Stage III Increased pubic hair, spreading to the pubic symphysis, curling and darkening
Stage IV The area of pubic hair expands and approaches adult features, but remains concentrated on the upper border of the pubic bone and does not extend to the inner thighs
Stage V Adult-type pubic hair distribution, extending to the inner thighs