What is the difference between primary and secondary amenorrhea?

Updated: Oct 14, 2019
  • Author: Kristi A Tough DeSapri, MD; Chief Editor: Richard Scott Lucidi, MD, FACOG  more...
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Primary amenorrhea is defined either as absence of menses by age 14 years with the absence of growth or development of secondary sexual characteristics (eg, breast development) or as absence of menses by age 16 years with normal development of secondary sexual characteristics.

Secondary amenorrhea is defined as the cessation of menstruation for at least 6 months or for at least 3 of the previous 3 cycle intervals. Because only 3 diagnoses are unique to primary amenorrhea and never cause secondary amenorrhea, differentiating primary from secondary amenorrhea does little to enhance the clinician's understanding of the etiology.

Diagnoses unique to primary amenorrhea include vaginal agenesis, androgen insensitivity syndrome, Turner syndrome (45,X), and mosaicism. The remaining diagnoses should be considered in patients with both primary and secondary amenorrhea.

Since regular menstruation reflects a properly functioning hypothalamic-pituitary-gonadal axis, a logical approach is to consider disorders based upon the levels of control of the menstrual cycle: uterus, ovary, pituitary, and hypothalamus.

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