What is menstruation? Menstruation is your monthly period. During menstruation, your body releases hormones (special chemicals) to help prepare for pregnancy. As the levels of hormones increase, the lining of your uterus becomes thicker. During the middle of the menstrual cycle, ovulation occurs. Ovulation is when the ovaries release an egg. If the egg does not get fertilized, it passes through the uterus and out of the body. The lining of the uterus, together with blood and mucus, breaks down and sheds. This blood flow passes through the vagina and causes your monthly period.

When does menstruation begin and end? Some girls may have their first period at 9 years of age, while others begin at 16 years or older. Most women start to have a monthly period at about 12 years. Menopause is the time in a woman's life when monthly periods stop. This usually occurs at age 50 or older.

What happens each month? Each period may last for 2 to 7 days and can be light, moderate, or heavy. The total amount of blood loss may be 1 to 4 tablespoons (20 to 60 milliliters) for the whole menstrual period. This amount may be different among women and it may be different for you from one period to another.

What symptoms may I feel during menstruation? Premenstrual syndrome (PMS) is a group of physical, emotional, and mental changes that you may have before your monthly periods. These symptoms are caused by an increase in hormones. They include headache, dizziness, bloating, and nausea. You may also feel very tired, have breast swelling or soreness, and problems with sleep. You may have mood changes, such as feeling grumpy, sad, or emotional. These symptoms usually go away when your monthly period starts. Ask your caregiver for more information about PMS and how symptoms can be controlled.

What conditions may prevent menstruation or make it irregular? Your menstruation may be irregular for 2 to 3 years after your monthly period begins. Other things that can prevent menstruation or make it irregular are:

How can I care for myself during menstruation?

When should I contact my caregiver? Contact your caregiver if:

When should I seek immediate care? Seek care immediately or call 911 if:


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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