Early Breast Development

Dear Lisa,

My six year old daughter has breast. She started to show around age 5. We have taken her to her Pediatrician but she is puzzled. She has had several tests done but nothing is showing up. She is a very slim child who does not drink a lot of milk. What advise can you give my wife and I?

“Puzzled Parents”

Dear “Puzzled Parents”,

Young girls develop breast enlargement for a many reasons. Some of the possible causes include a benign mass such as a vascular Harmatoma or Hemangioma, swelling from an injury, infection due to Staph, exposure to certain medications, or the ingestion of estrogen containing products. It is extremely rare for breast enlargement or a mass in a child to be due to cancer. Primary breast cancer in the pediatric and adolescent age group is less than 0.2% (1) Sometimes what is thought to be breast tissue is really adipose tissue or fat in an overweight child. (2) Overweight children commonly appear to have increased breast tissue without any real increase in actual glandular tissue. Since you mentioned that your daughter is “very slim” this should not play a part in your situation. You did not report that your daughter is taking any medication, therefore medication side effects in your daughter’s case is also not a factor.

Normal breast development is expected to occur between 8 and 13 years old. A female who presents with breast enlargement before 7 years old should have an evaluation in order to determine its cause.(1) The typical work up for a young girl with breast enlargement typically includes a physical examination, blood work for hormone and thyroid levels, a bone age x-ray and in some instances an MRI. It is good news that your daughter’s physical examination and testing turned out normal because this rules out an organic cause for her early development. Once it is determined that a young girl’s breast enlargement is truly breast tissue and all other disease states have been ruled out she is considered to have Premature Thelarche.

Premature Thelarche is defined as unilateral or bilateral breast development with no other pubertal changes before 7 years old.(1) Premature Thelarche is thought to be caused by an exaggerated response to normal levels of hormones. In other words the body of a child with early breast development responds to normal levels of hormones differently than other children. Usually the size of the breast enlargement in young girls regresses slowly over 6 months to 6 years. In a few cases the breast enlargement may persist into puberty. (1) Once a young girl develops Premature Thelarche, she should be monitored for a condition called Precocious Puberty. In some cases Premature Thelarche is an early sign that Precocious Puberty is developing. One study showed that 14% of girls with Premature Thelarche developed Precocious Puberty.(3)

Precocious Puberty is the development of secondary sexual characteristics before 8 years old in girls and before 9 years old in boys. In this condition a child has elevated sex hormone levels in their blood and displays signs of sexual maturation. The symptoms include development of pubic hair, axillary hair growth, breast enlargement in girls, advancement of bone age, linear growth spurt, increased appetite, and emotional liability. (4) Once a young girl is diagnosed with Premature Thelarche or early development of breast tissue she should be checked every 3 to 6 months by her physician for signs of Precocious Puberty. In addition, parents should watch for the signs of precocious puberty at home and bring it to the doctor’s attention if it occurs. If signs of precocious puberty develop, a child should be referred to a Pediatric Endocrinologist for further work-up and treatment.

During my practice I often came across young girls with Premature Thelarche. Most of the cases were idiopathic, which means not due to an organic cause. Parents were instructed to watch for other signs of sexual maturation, in most cases this did not occur. You and your wife did the right thing by bringing your daughter to her physician for evaluation and testing when you noticed changes in her breast appearance. At this point it is important to monitor your daughter for signs of sexual maturation and contact her Pediatrician if they occur. You can do this by casually observing her when she is changing or bathing without bringing too much attention to the situation.

It would be a good idea to plan supervised play dates, avoiding play that involves dress up or changing clothes in front of her friends. Activities that do not draw attention to her breast development will prevent your daughter from feeling self conscious and feeling different from the other girls. Wearing clothes that are loose fitting and in layers will detract attention away from her breast development. Also, it is important to teach your daughter the concept of privacy, instructing her that dressing should be done behind clothes doors when she is alone. You should also explain to her that no one has the right to look at or touch her body. The good thing is that soon some of her girlfriends will start to develop. Since the normal age for breast development may start as early as 8 years, in a couple of years her friends will not appear so different from her.

(1)Spark R. Unilateral breast enlargement in a 6-year-old-girl. The Clinical Advisor. 2006. March:114-119.
(2) )Schwartz M, Charney E, Curry T, Ludwig S. Pediatric Primary Care. A Problem Oriented Approach. 2nd Ed. Littleton, Mass:Year Book Medical Publishers, Inc 1990: 169-172.
(3)Van Winter JT, Noller KL, Zimmerman D, Melton JL. Natural history of premature thelarche in Olmsted County , Minnesota,1945-1984. J Pediatr. 1990;116:278-280.
(4)Graham M, Uphold C. Clinical Guidelines in Child Health. Gainsville, Florida: Barmarrae Books. 1994:124-126.

Lisa-ann Kelly R.N., P.N.P.,C.
Certified Pediatric Nurse Practitioner

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