Chapter 11 - Primary and Secondary Amenorrhoea

Summary

Amenorrhoea is a medical term that is used to describe the absence of menses, which is classified into primary and secondary amenorrhoea. Primary amenorrhoea is encountered in approximately 3% of the population and refers to the concurrent absence of onset of menstruation (menarche), normal growth, secondary sexual characteristics including breast development (thelarche) and growth of pubic hair (adrenarche) when a girl reaches the 13th year of life [1]. The age of menarche varies in the general population; however, it is generally considered that the majority of young girls will experience menarche between the 10th and 16th years of life. Thelarche and adrenarche usually precede the onset of menarche by a period that may vary between a few months and two years. When normal growth is present and secondary sexual development is observed, absence of menstruation is considered normal until the age of 15; however, when this threshold is exceeded primary amenorrhoea is also diagnosed. This threshold is somewhat lower compared to that described in traditional handbooks (16 years of life); however, it is justified by current worldwide trends that seem to suggest a progressive lowering in the age of menarche. In the absence of growth or secondary sexual characteristics, primary amenorrhoea is defined as the absence of menstruation before the age of 14 years.