Confused and have questions? We’ve got answers. With Chegg Study, you can get step-by-step solutions to your questions from an expert in the field. If you rather get 1:1 study help, try 30 minutes of free online tutoring with Chegg Tutors.


From Biology-Online Dictionary | Biology-Online Dictionary
Jump to: navigation, search



The absence, discontinuation, or abnormal stoppage of menstrual period in a woman of reproductive age


Menstruation is the recurring discharge of blood, cervical mucus, vaginal secretions, and endometrial tissue of a nonpregnant females of humans and other animals (e.g. certain primates, shrews, and bats.1 The first menstrual period (menarche) occurs at the onset of puberty. In humans, it occurs usually at ages between 12 and 15.

There are instances though when menstrual period is different from the norm. Amenorrhoea is one of them. It pertains to the absence or abnormal stoppage of menstrual period. Normal causes of amenorrhoea are pregnancy and lactation. Mothers that are fully breastfeeding their young may experience amenorrhoea and the condition is called lactational amenorrhoea. The total stoppage of menstrual periods after reproductive age is referred to as menopause.

Amenorrhoea may also be classified as primary or secondary. The primary type of amenorrhoea is characterized by menstruation cycles not starting. The absence of menarche may be due to the congenital absence of uterus. Secondary amenorrhoea is the ceasing of menstrual cycles that is usually caused by hormonal disturbances from the hypothalamus and the pituitary gland.


  • amenorrhea (US spelling)

See also:

1 Lopez, K. H. (2013). Human Reproductive Biology. Academic Press. p. 53.