What is puberty?
Puberty is the process of physical changes through which a child’s body matures into an adult body capable of sexual reproduction. Puberty involves hormonal changes that cause growth spurts, the development of secondary sexual characteristics, and psychological changes. Puberty typically begins between ages 8 and 14 in girls and ages 9 and 15 in boys. The process can take up to 4 years.
Puberty happens because the pituitary gland begins releasing more hormones. This signals the production of estrogen and testosterone, which cause the physical changes of puberty. Growth spurts occur because estrogen increases the production of growth hormone. Body fat composition changes as hormones affect metabolism. Pubic and underarm hair develops as a response to rising androgen levels. Genitals enlarge as testosterone increases. Boys may begin having erections and ejaculations. Girls’ ovaries enlarge and menstrual periods begin as ovulation starts.
When does puberty start?
The timing of puberty varies widely and is influenced by both genetic and environmental factors. Puberty typically begins between ages 8 and 14 in girls and ages 9 and 15 in boys. Some signs that puberty is starting:
– Girls: Breast development, pubic hair, accelerated growth, acne. Menarche (first period) usually occurs later.
– Boys: Testicular enlargement, pubic hair, penile growth, accelerated growth, acne, deepening voice.
However, the age range is broad. Some girls may start puberty as early as age 7 or 8, while others may not start until 13 or later. A number of factors can contribute to early or late onset of puberty, including family history, body fat percentage, exposure to chemicals, and various medical conditions. It’s important not to worry about being “normal” but talk to a doctor if puberty seems excessively early or late.
What are the stages of puberty?
Puberty is a multi-year process of hormonal and physical changes that goes through several stages:
Prepubescent
– No visible signs of puberty. Physical characteristics of a child.
Adrenarche
– Early hormonal changes. Slight pubic/underarm hair growth may occur.
Gonadarche
– Activation of the gonads (ovaries/testes). More visible signs of puberty begin:
– Girls: Breast and hip development, more rapid growth, vaginal discharge, pubic hair. Menarche typically occurs late in this stage.
– Boys: Testicular and penile enlargement, pubic hair, first ejaculation, voice changes.
Completion of Growth
– Puberty is completed when adult genitalia and secondary sex characteristics have fully developed and rapid growth slows down as the sex hormones plateau. Typically occurs by ages 15-17.
The process takes around 4 years on average but varies considerably based on when puberty began. Talk to a pediatrician if puberty seems excessively prolonged.
What causes puberty to start?
The onset of puberty is initiated by the hypothalamus, a gland in the brain that signals the pituitary gland to release hormones that stimulate the gonads (ovaries and testes). This starts a cascade effect of increased estrogen and testosterone.
Several factors influence the timing of puberty:
– Genetics – Family history is a major factor. Girls tend to start around the same age as their mother.
– Body fat – Leptin from fat cells helps regulate hormones. Increased body fat can trigger early puberty.
– Environmental factors – Chemical exposure, nutrition, stress levels, and socioeconomic factors may play a role.
– Medical conditions – Chronic disease, hormone deficiencies or abnormalities, tumors, and other conditions can influence puberty timing.
While genetics are a big contributor, the trend toward earlier puberty is likely also influenced by improved nutrition and greater prevalence of obesity. Stress and environmental chemicals are other areas of scientific study.
How do hormones change during puberty?
The main hormones involved in puberty include:
– Gonadotropin releasing hormone (GnRH) – Released by the hypothalamus, it activates the release of other hormones.
– Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) – Pituitary hormones stimulated by GnRH. In girls, LH/FSH cause estrogen production and egg maturation. In boys, LH stimulates testosterone production and FSH stimulates sperm maturation.
– Estrogens – In girls, estrogens support breast development, female body fat distribution, menstrual cycles, and maturation of the vagina, uterus, and ovaries.
– Testosterone – In boys, testosterone from the testes causes growth of the penis and testes, voice deepening, increased muscle mass and strength, bone growth, body hair, and motivates sex drive.
– Growth hormone – Increases in response to estrogens. Contributes to growth spurts and bone elongation.
The complex interplay between these hormones results in the changes of puberty as the body converts from child to adult reproductive capacity. The hormonal changes continue until the late teenage years when adult hormone levels are reached.
How do boys and girls bodies change during puberty?
Some key physical changes that occur during puberty:
Boys:
– Testicles and penis enlarge
– Pubic, facial, body, and underarm hair grows
– Voice deepens as vocal cords lengthen
– Rapid muscle development
– Shoulders broaden as growth plates widen
– Increased sweat and oil production may cause acne
– Wet dreams and erections begin as sperm production starts
– Growth spurt peaks around age 14, then slows
Girls:
– Breast tissue starts developing as early as age 8
– Ovaries and uterus enlarge
– Pubic and underarm hair develops
– Hip bones widen and curves develop
– Menstruation and fertility begin
– Increased fat in hips, thighs, and rear
– Rapid growth spurt around 12, then slows
– Increased sweat and oil production may cause acne
– Growth typically ends around 15-17
The sequence and pace of changes varies. Talk to a pediatrician if puberty seems too slow or fast.
What are secondary sex characteristics?
Secondary sex characteristics are physical features that distinguish the two sexes, but aren’t directly part of the reproductive system. They develop during puberty due to rising sex hormone levels:
Males:
– Facial hair
– Deepened voice
– Muscle growth
– Body hair
– Broad shoulders
– Adam’s apple
Females:
– Breast growth
– Wider hips
– Estrogen fat distribution to hips/thighs
Both:
– Underarm/pubic hair
– Acne
– Body odor
These traits signal sexual maturity and become more pronounced as puberty progresses. However, they aren’t fully defined until the late stages of puberty.
What are the emotional changes during puberty?
In addition to physical changes, puberty brings many emotional and psychological changes as well due to hormonal fluctuations and changes in brain development:
– Self-consciousness about one’s body
– Mood swings and emotional sensitivity
– Feeling embarrassed easily
– Increased interest in relationships
– Concerns about social acceptance
– Conflicts with parents over growing independence
– Experimentation and risk-taking behavior
The brain also undergoes structural changes during adolescence, increasing emotional intensity. Teens are more vulnerable to stress, depression, and peer pressure. Providing a supportive environment helps them through this emotionally challenging transition.
When do girls start their periods?
Menarche is the beginning of menstruation and one of the later signs of puberty in girls. The average age of first periods is around 12, but can range from 8 to 16.
Periods are triggered by hormonal cycles that cause ovulation and preparation of the uterus for pregnancy each month. Several factors influence when periods begin:
– Genetics – Girls often start around the same age as their mother and other female relatives.
– Body weight – Increased fat reserves may trigger earlier periods. Athletes and underweight girls tend to start later.
– Medical conditions – Chronic disease, hormone problems, and other issues can affect menstrual onset.
– Environmental factors – Chemical exposures, nutrition, and stress may play a role.
Remember, menarche is just one step in puberty. Other changes like breast development often start 1-2 years before the first period. See a doctor if periods haven’t begun by age 15.
How long after breast buds do periods start?
Breast development (breast buds) often begins between ages 8-13 and occurs before most of the other changes of puberty. Menstruation usually happens fairly late in puberty, around 1-2 years after breast budding starts. However, the length of time between breast budding and menarche (first period) varies widely.
Some girls may start their periods before there is significant breast development. Others may have well-developed breasts for a year or more before getting their first period. Stress, nutrition, body weight, genetics, and medical conditions can all influence the timing and pace of changes.
As a rough estimate, periods tend to begin about 2 years after breast budding starts. But what’s “normal” varies a lot between individuals. The most important thing is to watch for consistent progress through the changes over time. Contact a doctor if development seems stalled for more than a few years or menstruation hasn’t begun by age 15.
How long does puberty last?
The process of puberty typically takes about 4 years from the early signs of hormonal shifts to full sexual maturity. However, puberty includes several gradual stages and wide variation is normal in the timing and order of changes.
Some markers of the typical puberty timeline:
– 8-13 years old – Early signs like breast budding may begin
– 10-14 years old – More visible changes occur: pubic hair, voice changes, periods, acne
– 12-16 years old – Peak growth spurt occurs
– 15-17 years old – Development slows and reaches adult stage
The duration also differs between boys and girls. Girls tend to start puberty earlier (around ages 8-11) but complete the process by 15-17. Boys begin later (around ages 9-14) but continue maturing until around age 17-19.
With the normal variation, puberty may take anywhere from 2 to 5 years. Talk to a pediatrician if signs lag significantly or puberty seems rushed.
How does puberty affect growth spurts?
Growth spurts are periods of rapid height increase during puberty due to the effects of rising estrogen and testosterone levels. Girls typically have their growth spurt between ages 10 and 14, peaking around 12. Boys’ growth spurt occurs later, between 12-16, peaking around 14.
During peak growth, some teens may gain 4-6 inches per year before the rate gradually declines. Total growth during puberty usually amounts to:
– Girls: 8-9 inches gained
– Boys: 10-12 inches gained
Rapid bone growth happens first in the long bones of the arms and legs. As estrogen circulates at high levels, growth slows and shifts to widening the pelvis and hips in girls. Spurts in boys continue longer since testosterone levels don’t plateau as early.
Along with the growth spurt, weight gain increases due to appetite hormones, muscle growth, and changing body composition. Hands and feet may grow faster than arms and legs. Rapid growth may cause clumsy coordination for a period.
What causes pubertal growth spurts?
The rapid growth that happens during puberty is triggered by rising levels of estrogen, testosterone, and growth hormone:
– Estrogen – Initially promotes rapid bone lengthening in both sexes. Also guides fat distribution and hip widening in girls.
– Testosterone – Stimulates muscle growth, bone expansion, and longer duration spurts in boys.
– Growth hormone – Increases due to estrogen’s influence. Makes bones elongate and mature faster.
– IGF-1 – Growth hormone triggers the liver to produce more IGF-1, which speeds up bone and tissue growth.
Genes dictate the overall growth potential via factors like peak hormone levels. Environmental factors like nutrition influence how much of that potential is reached. The coordinated effects of these hormones initiate the body’s maturation into an adult capable of reproduction.
When does hand and feet size stop growing in puberty?
Growth of the hands and feet accelerates at the beginning of puberty, often before arms and legs lengthen. This causes the awkward appearance of large hands and feet compared to shorter limbs for a while.
Feet typically stop growing between ages 13-17 in girls and 14-20 in boys. Hand growth completes around ages 15-17 in girls and 16-21 in boys. However, the exact timing varies:
– Girls’ hands and feet may finish growing by age 14 or as late as age 17.
– Boys’ hands continue growing into the late teens. Feet may grow into the early 20s.
Growth plates in the bones of hands and feet fuse by the end of puberty. Estrogen speeds up bone maturation in girls, while testosterone extends the growth period longer in boys. Full adult shoe and ring sizes are usually reached by the completion of the teenage years.
Voice changes during male puberty?
As testosterone levels rise during puberty, boys experience voice deepening between ages 11-18 due to vocal cord growth:
– Larynx (voice box) grows: The cartilage enlarges and vocal cords become longer and thicker. This deepens the range of sounds.
– Vocal muscles strengthen: Increased thickness allows the vocal cords to vibrate more slowly, producing lower tones.
– Voice “cracks”: As the larynx grows, the vocal cords don’t always vibrate together properly. This leads to voice cracks and instability.
– Eventual lowering of pitch: The voice will settle into a lower, more mature-sounding range over 1-2 years. Voice changes usually complete by age 15.
Boys also develop an Adam’s apple – a protrusion in the throat from thyroid cartilage growth. Voice changes can be embarrassing at first. But these physical developments are a normal sign of male maturation.
What causes severe acne during puberty?
Acne flare-ups are common during puberty due to hormonal changes that increase oil production in the skin. Higher levels of androgens, like testosterone, cause the sebaceous glands to enlarge and produce more sebum. Excess sebum mixes with dead skin cells and clogs pores, allowing bacteria growth and inflammation – the primary causes of acne.
In addition to androgen effects, other puberty-related factors can worsen acne:
– Rapid skin cell turnover – More cells shed into pores.
– Oily hair – Can transfer oils to the skin.
– Sweat – Adds moisture that bacteria need to thrive.
– Stress hormones – Can increase oil and inflammation.
For some teenagers, the surge of androgens during puberty will greatly exacerbate acne. Severe acne may require prescription treatments. Seeing a dermatologist can help identify solutions to achieve clearer skin. The acne prone phase usually improves after puberty as hormones rebalance.
How can parents talk to kids about puberty?
Tips for parents communicating with kids about puberty:
– Start early – Begin discussing puberty basics by age 8-9 before physical changes start.
– Make it ongoing – Have regular casual talks rather than one big discussion.
– Be positive – Don’t convey that puberty is embarrassing or negative.
– Get comfortable – Be open and honest using proper terms for anatomy.
– Listen and ask questions – Let your child’s curiosity guide the details.
– Keep it age-appropriate – Explain puberty in ways kids can relate to their experience and maturity level.
– Use media carefully – Books, videos, etc. can spark discussion, but review first.
– Encourage questions – Don’t require kids to talk, but let them know you’re ready to listen if needed.
– Respect privacy – Kids need to know parents will not invade personal boundaries.
– Be understanding – Puberty can be an awkward, scary time full of new sensations and complex emotions.
Conclusion
Puberty is the biological process of transitioning from child to adult. While the specific changes and their timing varies widely, puberty typically begins between ages 8-14 and ends by ages 15-17. Signs like breast development, menstruation, voice changes, and growth spurts result from complex hormonal signals. Along with physical changes, brain development causes shifts in emotions, cognition, and social behavior during the adolescent years. By understanding the broad range of healthy norms in puberty onset and progression, parents can provide better support and guidance to ease this transitional stage.
