A sanitary towel (aka. a sanitary napkin, a feminine napkin, a menstrual pad)) is an absorbent item worn by women in their
underwear when
menstruating, bleeding after
giving birth, recovering from gynecologic surgery, experiencing a miscarriage or abortion, or in any other situation where it is necessary to absorb a flow of blood from the vagina.
Sanitary towel is a common term to hear in the UK.