Why are Girls Getting Their Period Earlier?

Last updated: March 3, 2020

Contributed by:
Nerissa Bauer M.D.
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Thank heaven for little girls, but what happens when childhood gets cut short with early puberty? More and more girls are putting down dolls to pick out bras and stock their cupboards with tampons as the age of onset puberty continues to fall.


The average age of a girl’s first period in the United States and Europe was about 16 a century ago. Today, it’s closer to 13.


So why are girls starting puberty earlier and is there anything that can be done about it? We asked our resident expert, Dr. Nerissa Bauer for her insight.



What is Puberty?

why are girls entering puberty earlier?

Source: Canva

Puberty is described as the beginning of fertility and includes the development of breast buds, pubic hair, a growth spurt and first ovulation and menstruation.


In females, the normal onset of puberty ranges from 8 to 13 years old, averaging age 10 years in White Americans and age 8.9 years in African-Americans.  15 percent of all girls have breast development when they are 7, and 10 percent have pubic hair by then. By age 8, more than 25 percent are developing breasts, and almost 20 percent have pubic hair.


The first stage of puberty for girls is the development of breast buds. In the United States approximately 50 percent of females will have attained this stage of development before age 10. While some parents may mistake extra fat for developing breasts, there are subtle differences.


It can be hard to tell at times, however the contour of the breast will be different. Your child’s doctor will also look for other signs of puberty in addition to breast bud development. Girls may complain of tenderness as well.


The onset age for puberty has fallen in many developed countries. Research shows in northern Europe first fell in the 1800’s and then another three years in the last century. Public health successes and changes in social structure are believed to be responsible for the change.


What are the Risks?

breast development is the first sign of puberty

Source: Canva

The earlier before age 12 a girl starts her period, the higher her lifetime risk for breast cancer This is likely from the prolonged estrogen exposure.


The highest average risk for breast cancer in non-Hispanic white women, where it is 1 in 8, or 12.5%. In all girls who start their periods before the age of 12, taken together, the risk is 16.25%.


As she reaches maturity, she needs to be made aware of controllable risk factors for breast cancer, such as the use of estrogen-containing birth control pills (10 years of use would raise her risk to about 22%), first pregnancy after age 30 (if she did this, it would raise the risk to about 35%), high-fat diet, alcohol use, fertility drugs, pesticides, and radiation exposure. Each of these factors multiplies her accumulated risk.


Another risk is the gap between the age the child is physically mature and the age the child is emotionally mature. One study showed a link between early puberty and an increase in teenage pregnancy, STDs, bullying, and narcotic use.


Related: I’ve had my period for 30 days! What should I do?




Why are we Maturing Faster?

environmental stress, such as divorce, can lead to an early period

Source: Canva


While there is no clear cut reason, research is pointing to a host of possible causes working together.


Environmental Stress

One study showed that environmental stress can play a role in early menstruation. The study particularly looked at the rates of divorce as well as conflict between mother and daughter and showed a link between these stresses and earlier menstruation.


For example, girls who grow up with domestic violence or without a biological father in the house are more likely to get their periods earlier than other girls. The theory is that the brain perceives this chronic stress as a low-grade threat, triggering the brain to start reproduction as soon as possible.link between toxic stress and the earlier onset of puberty. For example, girls who grow up with domestic violence or without a biological father in the house are more likely to get their periods earlier than other girls. The theory is that the brain perceives this chronic stress as a low-grade threat, triggering the brain to start reproduction as soon as possible.


Financial Stress

Another study looked at the role finance plays in menstruation. It found that girls in the lowest financial standing were twice as likely to experience early menstruation as those in the highest financial standing.



Research by Louise Greenspan, M.D. determined the largest risk factor for early puberty may be obesity. Fat is a very active hormonal gland, and fat cells convert other hormones into estrogen. The more fat tissue a girl has, the higher her chance of starting puberty earlier. What we don’t know is whether obesity is the actual cause, or if there is some other common cause that triggers obesity and puberty in the first place (which obesity then makes worse).


Chemicals to Blame?


Chemical flame retardants, for example, polybrominated biphenyls (PBBs) have been linked to earlier menstruation in girls and with earlier puberty. Similarly, high levels of dioxin exposure have been associated with elevated risks for breast cancer and early menstruation.


Precocious Puberty

getting period earlier is part of earlier period

Source: Canva


Early puberty, known as precocious puberty, is characterized by sexual characteristics in females before age 8 and age 9 in males.


According to Stanford Children’s Health, precocious puberty may be caused by tumors or growths of the ovaries, adrenal glands, pituitary gland, or brain. Other causes may include central nervous system abnormalities, family history of the disease, or certain rare genetic syndromes. In many cases, no cause can be found for the disorder.


It can also cause the child to stop growing before they reach their full genetic height.


Early maturation in girls is categorized in two main types: rapidly progressive and slowly progressive. Most girls who begin puberty early (especially those who begin before age 6) have the rapidly progressive variety. They go through each of the stages (including closure of the growth plates of the bones) at a very rapid pace, and thus lose much of their adult height potential. About 1/3 of these girls will end up shorter than the 5th percentile of adult height. Many girls, however (particularly those beginning puberty after their 7th birthdays), will start puberty early, but still go through each of the stages at a more typical pace. While their “adolescent” growth spurts are over early, they will continue to grow until their bones reach final maturity at about age 16.


Precocious puberty is 10 times more common in girls than in boys. Sexual development may begin at any age. Pregnancy has been reported as early as 5 1/2 years old.


Related: Preventing HPV and cervical cancer in women

How to Handle (Early) Puberty

teen in early puberty crying

Source: canva


The most important thing is to open the lines of communication between you and your child. Let their questions guide the discussion. Sometimes kids are not ready or feel embarrassed, if this happens, you can offer your child an appropriate book and offer to read with them or let them read it but check in and then ask if they have questions about anything they read.


However it is important to help normalize the process and let them know you are willing and able to answer any questions or worries they may have. You may consider sharing your own experiences and if you also felt confused or awkward but that everyone goes through these changes.


What are some best practices for helping a young child with their first period?


Talking with your child about how they are feeling is always first. They may be scared, confused or shocked. Help reassure them that you will be helping them know what to do and that it is a part of growing up. Helping your child have supplies such as pads, tampons or panty liners at the ready  in a small pouch to keep in a bag or locker and knowing what to do and how often will help.


How do you know if the arrival of an early period should be a cause for concern?


Puberty happens in stages and starts between 8-14 for girls. Breast budding usually occurs first in girls with periods happening towards the end, usually 2 years later. If periods happen before earlier stages of development, such as breast development and appearance of pubic hair, or if signs of puberty arise before age 8, parents should see their child’s doctor. When this happens it is called precocious puberty and these children will need a medical work up by a pediatric endocrinologist.


Is a 9 year-old child mature enough to handle the responsibility that comes with having her period?


Nine years-old is on the early side of puberty and thus these girls may not yet be emotionally ready. Cognitive development happens in stages and in the case of a young girl having her period at nine means her emotional growth is likely not at the same pace.


Parents should continue to express a desire to talk and help them understand what is happening, how they may feel especially compared to other girls whose bodies have not yet started changing or just starting to change. Girls who are “early bloomers” may be more self conscious and realize they are different from their peers. Making sure to be available to them emotionally will be important


If my child menstruates early, does that mean they are going to stop growing?


Girls will have a growth spurt and expect to gain 2-2.5 inches a year.They can gain height during puberty but usually up to two years after menstruation.


Should you be Concerned?


Puberty is not an easy time-for mother or daughter. If you are concerned about your daughter’s development, you can always chat confidentially with one of our doctors. Don’t lose sleep over your child’s development. Connect with us for some medical advice within minutes.


Disclaimer: This article provides general information and is not intended to diagnose, treat or cure any disease or medical condition. If you require specific advice, please consult one of our medical professionals through the app. However, in case of an emergency, please call 911.

About Nerissa Bauer M.D.

Dr. Bauer is a blogger on parenting topics on her blog, www.letstalkkidshealth.org. She is a tweetiatrician (@nerissabauer) often advocating on behavioral and mental wellness topics, maternal depression, father involvement, high-quality child care and gun safety.

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