b'TheaverageageofmenopauseforwomenintheUKis51,buttheresalotofvariation,somenopausemayhappensoonerorlaterthanthis.Formostwomen,themenopausedoesnthappenovernight.Thisisbecause,unlesstherehasbeenasurgicalmenopausewherethewombhasbeenremoved(Hysterectomy),theovariesdontsuddenlystopworking.Whathappensisthattheygraduallyslowdownoveraperiodoftimeaspartofthenaturalmenopause.Thistransitionperiodiscalledtheperimenopause,andcanlastforafewmonthsoryearstheaverageisaroundfouryears.ResearchbyHarvardMedicalSchoolsuggeststhatthevastmajorityofwomenwhodevelopsignificantmoodissuesduringperimenopausehavehadtheminthepast.Itsrelativelyrareforsomeonewithnohistoryofdepressionoranxietytosuddenlydevelopaseverecaseofitatmenopause.'