What is premature thelarche in precocious puberty, and what is the nature of prepubertal vaginal bleeding?

Updated: Nov 30, 2020
  • Author: Paul B Kaplowitz, MD, PhD; Chief Editor: Robert P Hoffman, MD  more...
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Premature thelarche is the appearance of breast development in young girls in the absence of other signs of precocious puberty (eg, growth acceleration, changes in uterine size and vaginal mucosa). It is typically seen in girls aged 3 years or younger. [34]  Breast tissue normally seen in the newborn period due to maternal estrogens can persist for a year or more in some infants. The keys to making this diagnosis include the following:

  • Observing that the child is growing in length along her established percentile channel
  • Noting that the amount of breast tissue increases only minimally over time (or may even decrease)
  • Observing a lack of thickening and pigmentation of the nipples and the areola as seen in girls with precocious puberty

The etiology of this condition is unknown. In some cases, small ovarian cysts that transiently produce estrogens may be responsible. In Puerto Rico, an epidemic of premature thelarche in the 1970s was suspected to have been caused by exposure to estrogens in poultry. Despite a lack of firm evidence, phytoestrogens in soy products and other environmental estrogen-like agents (eg, pesticides, phthalates) may have the potential to cause breast development in young children. Certain essential oils, in particular lavender-fragranced products commonly used in Hispanic communities, have been linked to early breast development, which resolves when exposure is discontinued. [35]

Prepubertal vaginal bleeding

When a girl with little or no breast development has vaginal bleeding, this causes great concern for parents and providers. This condition, sometimes referred to as "premature menarche," has been well-described in the literature, although its cause is unknown. Studies show that hormonal levels are prepubertal, and pelvic ultrasonography shows a prepubertal uterus and ovaries. [36]  The bleeding can occur monthly but resolves in a few months, so reassurance and watchful waiting are often the best course. In persistent cases, a foreign body such as toilet paper may be found on pelvic exam.

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