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



A menstrual cycle disorder experienced characterized by infrequent menstrual periods


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 There are instances though when menstrual period is different from the norm. For instance, polymenorrhoea, oligomenorrhoea, and amenorrhoea are menstrual disorders that are characterized by the disorders of the menstrual cycle length.

Oligomenorrhoea is the medical term pertaining to that menstrual cycle disorder characterized by infrequent monthly periods. The menstrual periods are described as infrequent because the intervals of menstrual cycles are longer than the norm. In humans, the normal interval length (i.e. between the first day of a menstrual period and the first day of the next) is 21 to 45 days in young women, and 21 to 31 days in adults (an average of 28 days).2 Women with oligomenorrhoea have menstrual cycle intervals exceeding 35 days, with only four to nine periods in a year.3


  • oligomenorrhoea (US spelling)

See also:

1 Lopez, K. H. (2013). Human Reproductive Biology. Academic Press. p. 53.
2 Menstruation. Retrieved from [1].
3 oligomenorrhea. (n.d.) Gale Encyclopedia of Medicine. (2008). Retrieved from [2].