Puberty and Girls

Puberty consists of two developmental processes, thelarche and pubarche, both of which start during the grade school years and continue through adolescence. They overlap in time; each process takes years to fully complete.

Thelarche (Thee-lark-ee) is the medical term for the beginning of breast development. For 90% of girls, this is the first sign of puberty. It starts with a firm, round, tender lump (called a breast bud) under the nipple of one or both breasts. Girls may complain about feeling sore when they sleep on their stomachs; parents occasionally worry about the lump being a cyst or tumor. One side may develop considerably faster than the other. (This is normal). Some girls may be more comfortable if they begin wearing a soft bra or undershirt at this point, but others may prefer to wait.

Menarche (the first menstrual period) follows thelarche, and typically begins 1-1/2 to 3 years after breast buds appear.

Pubarche (Pyoob-ark-ee) is the appearance of pubic hair. For about 10% of girls, this may be the first sign of puberty. When it first begins to appear, pubic hair is typically light colored and straight; it becomes coarser and darker as girls mature. About two years after pubarche, hair begins to grow under the arms as well.

When Does Puberty Typically Happen?

In the United States, girls typically enter puberty between the ages of 10 and 15 years. On average, African-American girls begin puberty one year earlier than Caucasian girls, but many factors, including nutrition, physical activity, ethnic group, and body shape will influence the timing of puberty. Often girls will follow their mothers or their sisters with timing, but every girl is different.

It’s normal for Caucasian girls to begin developing breast buds as young as 7 years old; for African-American girls, they may be as young as 6. A pediatrician should evaluate breast bud development, or other signs of puberty, if they occur any earlier than this.

Is it True the Average Age of Puberty is Decreasing?

There is no evidence that the average age of puberty is decreasing. Girls as young as twelve or thirteen have been able to reproduce throughout history.

Our perception of puberty may be changing, however. In our society, it’s possible that girls are acting older, sooner. For example, prepubescent girls may be dressing, behaving, or speaking in ways that may be viewed as more appropriate for an older teenager.

Also, we know that girls with excess body fat will enter puberty earlier, on average, than girls without the additional body fat. This has always been the case; what may be changing is the amount of obesity in children.

How Do I Talk to My Daughter About Puberty?

Talking about the changes that come with growing up is one of our most important jobs as parents.

Your daughter will have questions about her changing body, even if she feels shy or embarrassed about asking them. Where will she get her answers? How accurate will the information be?

You want to be the one she turns to when she has questions, worries, or needs advice.

Even if your daughter has not started puberty by the time she is ten, some of her peers are. So, if you haven’t already, this is the time to start explaining words like tampon, period, vagina, and sex. She has probably heard these words already – so don’t shy away from them. You want her to take you seriously, so use real words, not slang.

By starting the conversation with her, you are letting her know that she can come to you when she is confused or scared about the changes taking place with her body.

You don’t need to know everything about puberty to be able to talk about it. Many parents are afraid their children will ask a question they can’t answer. Even if you are a single father raising girls, just opening the topic for conversation and letting her know that the changes in her body are normal and healthy will go a long way towards easing her fears.

Plus, we’re always here to help out if you don’t have all the answers.

For more information, see this AAP resource page, and check out the Puberty. Seriously? class for 9-12 year-old girls and their Moms (or other female mentors) that we offer here at Kids Plus.

Dr. Kerry McGee is a former Kids Plus provider.