P&G School Programs - Menstruation Demo


Back to Puberty	Explaining Menstruation Begin by explaining that menstruation is part of the female reproductive process. Every month or so, a woman’s body prepares for possible pregnancy with a pattern of changes known as the menstrual cycle. Explain that the use of a 28-day cycle is for teaching purposes and is based on the average length of a menstrual cycle. Emphasize that everyone has her own cycle, which varies from person to person, and even from period to period for the same person. These differences are normal. To help girls be better prepared for upcoming cycles, encourage them to mark the days of their period on a calendar (see "Instructor's Guide" page 13). They can do this with discreet marks, such as stars, flowers or smiley faces. Students can use BeingGirl.com — click on "About Me," then click "Period Predictor" — to help be prepared. There are four phases in the menstrual cycle, each controlled by rising and falling levels of hormones. The cycle can vary in length for each girl or woman. For purposes of discussing the four stages, a 28-day cycle is used. Although the cycle length is counted from the first day of menstruation, it is easier to explain if we start with the pre-ovulatory phase, before the egg is released. Pre-Ovulatory Phase, Days Six to 13 Each month, the pituitary gland and ovaries produce hormones. These hormones cause one egg in one of the ovaries to mature, or "ripen." Usually, the ovaries "take turns," each releasing a ripened egg every other month. At the same time, estrogen causes the lining of the uterus to get thicker, forming a soft cushion of blood and tissue (the endometrium). Ovulation Phase, Around Day 14 Around day 14, when the egg is fully mature, it is released by the ovary and starts traveling through the fallopian tube toward the uterus. Finger-like projections at the fallopian tube "reach out" to grab the egg as it leaves the ovary. Now the egg can be fertilized if sperm from a male are present. If fertilization occurs, a woman becomes pregnant. Premenstrual Phase, Days 15 to 28 The egg is on its way toward the uterus. In the meantime, the uterus is preparing for the egg’s arrival and builds up its lining with blood and tissue. If the egg has met a sperm in the fallopian tube (and been fertilized), it attaches itself to the endometrium. Here, the fertilized egg grows into a baby. However, if the egg gets to the uterus unfertilized, it breaks down and mixes with the endometrium. Menstrual Phase, Days One to Five This is the last phase of the cycle. If the egg has not met a sperm and been fertilized, the uterus does not need the extra lining of blood and tissue (the endometrium) to nourish a baby. So the lining dissolves into a reddish fluid and flows out of the body through the vagina. This usually lasts about three to seven days. The first day of the menstrual period is counted as day one of a new cycle. Around day five, a new egg starts to mature inside an ovary, and the cycle begins again.