formalHBH the time each month when a woman menstruates 经期，行经期SYN period
Examples from the Corpus
menstrual period• Not a menstrual period in the proper sense.• Five days after the end of the last menstrual period.• The danger time for development of tubal complications with gonorrhoea is the menstrual period.• When arranging your next smear, do not make an appointment during your menstrual period. 4.