Table of Contents
Definition of Menstruation
The final phase of the menstrual cycle, commonly called the menstrual period or simply the period. Menstruation is the discharge of blood and excess tissue that build up within the uterus as endometrium (the lining of the uterus) thickens and engorges with blood in preparation for the implantation of a fertilized ovum (zygote).
When pregnancy does not occur, hormonal changes cause the lining to slough away, passing from the uterus and out of the body via the vagina. Typically a woman passes two to three ounces of blood and other fluids over the course of the three to seven days she menstruates.
The menstrual flow is generally heaviest on the second through the fourth days. About 85 percent of women menstruate for four to five days; about 15 percent menstruate for six to seven days.
Women typically use disposable sanitary napkins (commonly called pads) or tampons to capture the menstrual flow. Pads have adhesive strips that attach them to underwear; tampons fit inside the vagina. It is important to change either pads or tampons every four to six hours to prevent overflow and maintain appropriate personal hygiene.
Tampons may irritate the vaginal walls. Because a tampon may carry bacteria into the vagina when the woman inserts, tampon use involves a slight risk for toxic shock syndrome, a potentially lifethreatening infection. Doctors recommend using pads at night and during other times when it might not be possible or practical for a woman to change her sanitary protection every four to six hours.
There are no health reasons for women to avoid their regular activities, including sports, bathing, and sexual activity if desired, during menstruation. Women may prefer to shower when menstruating.
Washing the genitalia with gentle soap and warm water is important to cleanse any accumulated menstrual fluids from the genital tissues, which reduces the presence of bacteria as well as improves comfort. Many women wear tampons during athletic activities such as bicycling, swimming, dancing, and running.
However, a woman should not sit in the bath tub or in a hot tub while wearing a tampon because the combination of heat and inactivity may draw bacteria into the vagina via the tampon’s removal cord, which extends from the vaginal opening. A woman should also change her tampon immediately after water activities such as swimming.
For further discussion of menstruation within the context of the structures and functions of reproduction and sexuality, please see the overview section “The Reproductive System.”
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