Normal endometrial thickness in a menarche patient should not exceed how many millimeters?

• A. 4 mm
• B. 8 mm
• C. 14 mm
• D. 20 mm

Answer: (C)

Endometrial thickness in puberty reflects estrogen-driven growth of the lining, but the uterus isn’t exposed to the same level of cycling as in a fully reproductive-age woman. In a girl who has recently begun menstruating, the endometrium can thicken with cycles but typically stays modest. An endometrial thickness up to about 14 mm is considered within the normal range for this age group. If the measurement exceeds roughly 14 mm, especially outside the expected phase of the cycle, it can raise concern for abnormal estrogen exposure (such as an estrogen-secreting tumor or exogenous hormones) and may warrant further evaluation. Smaller values like 4 mm or 8 mm can be normal in early or less stimulated states, while 20 mm would be unusually thick for a pubertal patient.