menstruation [ˌmɛnstruˈeʃən]

例句:

• Menstruation may cease when a woman is anywhere between forty-five and fifty years of age.
  女性停经是在45至50岁期间。
  
• Women enjoy special protection during menstruation, pregnancy , child birth and baby nursing period.
  妇女在经期 、 孕期 、 产期和哺乳期受特殊保护.
  
• What reason is the abdomen below the half moon before menstruation aches?
  月经前半月下腹疼是什么原因?
  
• Occasionally, menstruation just stops altogether with no warning.
  来自BBC
• Menstruation ceases permanently and you're no longer able to conceive.
  来自BBC
• Group menstruation on some soft furnishings as an act of rebellion?
  来自THETIMES