Nomenclature of primary amenorrhea: A proposal document of the Japan Society of Obstetrics and Gynecology committee for the redefinition of primary amenorrhea

Aim The aim of this study was to provide medical terms to describe the condition of a girl who should be evaluated for primary amenorrhea in order to facilitate intervention at an appropriate time. Methods We performed a literature and clinical guidelines search for recent practices with regard to menarche and discussed relevant cases that had been experienced by committee members. Additionally, we theoretically reviewed medical terms defined in the Glossary Book of Obstetrics and Gynecology in Japan (Japan Society of Obstetrics and Gynecology, 3rd edition). Results The committee for the redefinition of primary amenorrhea proposed the introduction of two terms and the deletion of one term that had been defined by the Japan Society of Obstetrics and Gynecology, instead of changing the age definition of primary amenorrhea. ‘Delayed menarche’ was introduced to describe a condition in which a girl has never experienced cyclic menstruation (menarche) by 15–17 years of age. ‘Late menarche’ was also introduced to describe a condition in which a girl has experienced menarche at 15 years of age or older. ‘Delayed menstruation,’ which was defined as a condition in which a girl experiences menarche at 15–18 years of age, was deleted. Conclusion The new terms ‘delayed menarche’ and ‘late menarche’ were introduced, and the term ‘delayed menstruation’ was deleted. The new system might help in the early detection and appropriate treatment of primary amenorrhea.