Detailed definition
The final menstrual period (FMP) is the date of the last menstrual bleed before permanent cessation of ovarian function. Because at the time of any given period there is no way to know it will be the last, the FMP is identified retrospectively after 12 consecutive months of amenorrhea in the absence of other causes (such as pregnancy, hysterectomy, or hormonal suppression). Once that 12-month criterion is met, the woman is considered postmenopausal, and the date of the prior bleed is recorded as the FMP. Median FMP age in the United States is approximately 51.4 years; ranges of 45–55 years are considered normal. FMP earlier than 40 indicates POI; 40–45 indicates early menopause. The STRAW+10 staging system uses the FMP as the central anchor (stage -1 is late perimenopause, stage 0 is the FMP itself, +1 stages are early postmenopause).
Why it matters in menopause
The FMP is what defines menopause clinically — the day a woman is officially "postmenopausal." It also matters for HRT: starting hormone therapy within 10 years of the FMP is associated with the most favorable risk-benefit profile (the timing hypothesis). For women whose menstrual history is interrupted (hysterectomy, IUD, hormonal contraception), the FMP can be impossible to date, and clinicians rely on age, symptoms, and labs instead.
Related terms
Sources
External references: Wikipedia.