Weighing the accuracy of Tanner staging

Tanner staging is a standard way of assessing puberty onset in both boys and girls, but there are some factors that can make an accurate assessment difficult even for experienced professionals.

Tanner staging uses pubic hair and breast development in girls to measure progress through the stages of puberty. A number of studies have suggested that obesity may be linked to an earlier onset of puberty1,2, but adipose tissue on the breast can also develop independently of real breast tissue3, thus skewing Tanner’s assessment.

Tanner staging is performed separately for pubic hair and breast development. The level of development observed for each, as seen below, is used to assign a stage of reproductive development.

Tanner staging for women4

Pubic hair

Stage 1: No hair Stage 2: Light, fluffy hair Stage 3: Thicker, darker (terminal) hair begins to develop Stage 4: Terminal hair covers the entire pubic triangle Stage 5: Terminal hair covers the entire pubic triangle pubic area and extends beyond the groin crease to the thigh

Breast Development Scale

Stage 1: No palpable glandular breast tissue Stage 2: A breast bud can be felt under the areola Stage 3: Breast tissue can be felt outside the areola, but there is no further development of the areola itself Stage 4: The areola develops above the contour of the areola breast Stage 5: The areola retracts into the contours of the rest of the breast and acquires darker pigmentation, papillae development and nipple protrusion

Assessing pubic hair growth isn’t usually a challenge, regardless of weight, says Katherine Kutney, MD, a pediatric endocrinologist at Rainbow Babies and Children’s Hospital in Cleveland, Ohio. However, the appearance of pubic hair does not always correspond to the onset of central precocious — or premature — puberty. Breast development is the main sign of the onset of puberty in girls, but overweight or obese girls may have excess tissue on the breast that can be mistaken for real breast tissue.

“Breast tan staging in overweight women is difficult because of lipomastia, but breast development as the key finding for physical examination to detect early central puberty is very important,” Kutney said.

Lipomasty can look like developed breast tissue, when it’s really just fat, Kutney said. However, she added that it is important to note that lipomastia can also develop along with real breast tissue.

“It’s hard to differentiate between these 2 scenarios,” explains Kutney. “Breast tissue is firm and exposure to estrogen makes the breast bud harder. If a palpable breast bud can be felt — even in the presence of lipomasty — it points to central puberty.”

If it’s still difficult to make an accurate assessment, Kutney recommended looking for other signs of early puberty, such as a growth spurt or vaginal discharge. Blood may also be taken to test hormone levels, but she cautioned that it’s possible for hormone levels to remain low or normal, even in cases of early puberty.

Kutney recommended that girls suspected of entering central precocious puberty be referred to a pediatric endocrinologist for a more thorough evaluation and possible intervention.

References

Lian Q, Mao Y, Luo S, et al. Timing of puberty associated with obesity and central obesity in Chinese Han girls. BMC Pediatrician. 2019;19(1):1. doi:10.1186/s12887-018-1376-4Brix N, Ernst A, Braskhøj Lauridsen LL, et al. Childhood overweight and obesity and timing of puberty in boys and girls: cohort- and sibling-matched analyses. Int J Epidemiol. 2020: 834-844. doi: 10.1093/ije/dyaa056Carlson L, Flores Poccia V, Sun BZ, et al. Early breast development in overweight girls: does estrogen made by adipose tissue play a role? Int J Obes. 43: 1978-1987. doi:10.1038/s41366-019-0446-5Emmanuel M, Bokor BR. Tanner stages. Stat Pearls Publishing. 2021.

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