When early thelarche should raise concerns

Although puberty can begin at a range of ages that vary by ethnicity, the current cutoff for diagnosing the process as premature is around age 8 years.

It can be difficult to age when early is too early, though, especially as girls continue to enter puberty at younger and younger ages.

Katherine Kutney, MD, a pediatric endocrinologist at Rainbow Babies and Children’s Hospital in Cleveland, Ohio. said thelarche, or breast development during puberty, is considered to occur prematurely when a girl reaches Tanner Stage 2¹—with a palpable breast bud beneath the areola—by age 8 years. Breast development without a breast bud is usually just a collection of adipose tissue and not a sign of true puberty.

Reaching Tanner Stage 2, with a palpable breast bud intact, by age 8 years may be a sign of early thelarche, Kutney noted, this isn’t always the case.

Parents are sometimes alarmed at breast tissue development in girls during infancy, but this is normal, Kutney explained. Exposure to maternal estrogen in utero triggers a physiologic mini-puberty that can last from birth to about 4 months of age. The mother’s hormones temporarily trigger the hypothalamic-pituitary-gonadal axis—which typically begins the process of puberty. In infants, this corrects after a few months as the mother’s hormones dissipate. Breast tissue may remain for the first 2 years of a girl’s life, but breast development that occurs without other signs of puberty, like growth spurts of pubic hair development, is considered benign, Kutney said.

Signs of benign premature thelarche include:

• Breast development that does not progress past Tanner Stage 3
• Breast development that occurs alongside a normal growth rate for the child’s age
• Breast development that occurs with normal or almost normal bone age

Early breast development and other signs of early puberty are a top reason for referrals for pediatric endocrinology specialists, but research suggests that early, or precocious, puberty is usually only considered to be a concern when breast development happens progressively over a 4- to 6-month period alongside a growth spurt.²

“My recommendation would be to refer any girl with thelarche persisting beyond age 2 years or occurring before age 8 years to pediatric endocrinology for evaluation,” Kutney suggested.

Some reports have suggested changing the guidelines for diagnosing thelarche because girls are entering puberty earlier and earlier.³ However, a 2016 clinical report from the American Academy of Pediatrics suggests to err on the side of using traditional guidelines over concerns that lowering the typical age for thelarche could lead to missed diagnoses of endocrine disorders.²

References

1. Emmanuel M, Bokor BR. Tanner Stages. StatPearls Publishing. 2021.
2. Kaplowitz P, Bloch C. Section on endocrinology, american academy of pediatrics. evaluation and referral of children with signs of early puberty.Pediatrics. 2016;137(1). doi: 10.1542/peds.2015-3732.
3. Eckert-Lind C, Busch AS, Petersen JH, et al. Worldwide secular trends in age at pubertal onset assessed by breast development among girls: a systematic review and meta-analysis. JAMA Pediatr. 2020;174(4):e195881. doi:10.1001/jamapediatrics.2019.5881