初しょ経けい

noun

menarche; first menstruation

Medical and formal term for a girl's first menstrual period. In everyday conversation, 初潮 (しょちょう) is more common.

See also: 初潮

• 初しょ経けいは通つう常じょう10代だい前ぜん半はんに起おこります。

  Menarche usually occurs in the early teens.

• 初しょ経けいの年ねん齢れいは個こ人じん差さが大おおきい。

  The age of first menstruation varies greatly among individuals.