noun which may take the genitive case particle 'no'
premenstrual
Medical and everyday term for the period before menstruation. Often used in compounds like 月経前症候群 (premenstrual syndrome).
月経前の症状には個人差があります。
Premenstrual symptoms vary from person to person.
月経前症候群はPMSとも呼ばれます。
Premenstrual syndrome is also called PMS.
生理前 is a more casual, everyday term for 'premenstrual', while 月経前 is more clinical.
Compound of 月経 (menstruation) and 前 (before). The kanji 月経 is a Sino-Japanese term for menstruation, literally 'monthly passing'.