Menstruation happens for most women about once a month, and that is why it is commonly called the “monthly period.” It usually lasts between three and seven days. It is a sign that a girl or woman can become pregnant if she has sexual intercourse. Women stop menstruating while they are pregnant and may or may not menstruate when they are breastfeeding.
Just as some girls begin puberty earlier or later than others, the same is true for periods. Some girls may begin to menstruate at age nine or ten while others may not get their first period until a few years later. A woman knows that she has started her period when a little blood comes out of her vagina. The blood does not pour like water from a tap. It comes out slowly, like a dribble. Usually by the time she has noticed a feeling of unusual wetness, her panties have absorbed any blood that has come out. This is why it is important to anticipate when each month she will start bleeding, so she can wear a sanitary pad or other protection to prevent clothing stains.
The amount of blood that comes out of the vagina can vary widely from person to person. Usually, an entire period consists of a few to several spoonfuls of blood – how much blood depends on the individual. The blood often starts off as a rusty or deep brown colour and then gets redder. It lightens to a rust colour again until it stops. The amount of blood can also vary from day to day.
The menstrual cycle is the period of time beginning on the first day of a woman’s period until the day before she begins her next period. Since this happens regularly, it is called a “cycle.” The length of time between one period and the next varies for each woman. For some, the cycle is 21 days (or fewer). For others, it is as long as 35 days or more. Irregular periods are common in girls who are just beginning to menstruate. It may take the body a while to adjust to all the changes taking place. For example, a girl may have the same length cycle for two months, then miss a month, or have two periods with fewer days in between them. Her menstrual cycle will probably become more regular, although she may continue to have irregular periods into adulthood. Sometimes she might have some spotting of blood for a day or two in the middle of her cycle. This is usually nothing to worry about. Stress or infections can disrupt a regular menstrual cycle.
Ovulation is the periodic release of a mature egg from the ovary. The time from ovulation to the next period is a very consistent length of 9 to 15 days and is controlled by hormones. The two weeks or so before ovulation and the two weeks after make a menstrual cycle about four weeks or a month long.