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.