What Happens Every Month
Every month, your body prepares for a potential pregnancy by an egg inside your ovaries. The egg is released and through the fallopian tube on its way to the uterus. If the egg the body sheds the uterine lining, causing a period that an average of four to eight days. Then the body begins again—uterine lining grows, an egg matures, is released, and so forth—a cycle that lasts about twenty-eight days. If you get pregnant, the cycles cease. Once you're no longer pregnant, they start again. In between, about one or two weeks before your period, you get awful headaches, backaches, and a variety of other PMS symptoms.
Things go on this way until you get older and start perimenopause, the transitional period before menopause. At this point, your periods become more erratic, and you start to experience some menopause-like symptoms, such as hot flashes. After twelve months without periods, you are officially in menopause. But there is so much more to the menstrual cycle. For one thing, a period involves a complex interaction of hormone levels that rise and fall over the course of cycle. These hormones not only control the biology of the menstrual cycle, but they impact how a woman feels: too much of one hormone may cause depression, while too much of another may cause anxiety. Monthly hormonal surges explain some of the emotional and psychological symptoms of PMS. In addition, there are a lot of variables, such as pregnancy, irregular ovulation, and contraceptives, that disrupt the typical menstrual cycle. There are also plenty of myths about menstruation that are just plain wrong, including the “fact” that every woman gets her period every twenty-eight days.
Fact
Perimenopause is the stage that precedes menopause when the production of hormones such as estrogen and progesterone diminishes and becomes more irregular.
Menstrual Myths
In the United States, the average age of menarche, or the onset of menstruation, is twelve, while menopause typically occurs around fifty (the average age is 51.4). Sometime in the decade before menopause, nine out of ten women also experience perimenopause symptoms, in which their cycles become more erratic. That means a woman will have her period for nearly forty years— potentially, a very long time to suffer from PMS!
The complexity of the menstrual cycle and the fact that many women aren't terribly familiar with their bodies or their cycles help perpetuate a number of myths about a womans' period, including the following:
Every woman’s cycle is or should be twenty-eight days long.
Every woman will or should ovulate every cycle.
If a woman bleeds, she is not pregnant.
A woman cannot ovulate or get pregnant when she period.
The menstrual cycle starts when periods end.
The Truth
It's perfectly normal to have a cycle that lasts twenty-one, twentyeight, or thirty-six days. Variation is normal, not only from woman to woman but also from month to month for any given woman. So you can have a cycle that is twenty-nine days one month and thirty-three days the next. The length of a menstrual cycle is tied to ovulation, which consistently occurs fourteen to sixteen days before a woman gets her period. This second half of the cycle is usually the same length. It is the first half, from the first day of your period until you ovulate, that can change from month to month.
Extreme variation, however, may signal an underlying health problem. If the pattern of your cycle goes wildly up and down— one month, twenty-one days, the next forty-five days, then eleven days, it can be a sign that you're not ovulating regularly. Similarly, if you get periods only two or three times a year, there could be a serious health issue involved. Note that variations in menstrual-cycle length are more common in young girls after they first get their periods and in older women who are undergoing perimenopause.
It's not unusual to skip a period once or twice a year. In fact, it's extremely common. This may be caused by stress, or, believe it or not, there may be no obvious reason. If you skip a period, it generally means you have not ovulated. What usually happens is that you ovulate next month and have a heavier flow than normal.
While technically not a period, some vaginal bleeding may occur while a woman is pregnant. A woman who takes contraceptives also does not get an actual period, but rather she experiences what's known as withdrawal bleeding.
Finally, if you’ve ever been confused when asked by your gynecologist when your last cycle began, here’s the answer. Your period actually starts on the first day of bleeding, not on the day your period ends.
Fact
Many women have cycles when they don’t ovulate and may not bleed. These are known as anovulatory cycles. Anovulatory cycles are not uncommon in the first twelve years after a girl starts to menstruate, in the first nine months after discontinuing oral contraceptives, during perimenopause, or in women who diet or exercise excessively.
Know Your Period: Biology Basics
The organs involved in menstruation are—surprise!—the brain (specifically, the hypothalamus), the pituitary gland, the ovaries, and the uterus.
Hypothalamus:This region of the brain regulates the menstrual cycle (it also regulates thirst, hunger, sleep patterns, libido, and other endocrine functions) by releasing a chemical messenger called follicle-stimulating hormone-releasing factor (FSH-RF) to stimulate the pituitary gland.
Pituitary gland: This “master gland” releases the follicle-stimulating hormone (FSH), plus a little luteinizing hormone (LH), into the bloodstream, which cause egg-containing follicles follicles in the ovaries to mature.
Ovaries:These two small glands, roughly the size and shape of almonds, store a woman's eggs, each in its own sac called a follicle. Under the influence of FSH and LH, the ovaries grow and mature ten to twenty follicles, until one is fully mature (the others simply die away) and bursts, causing ovulation.
Uterus:This pear-shaped organ grows a lining, called endometrium, which nourishes a fertilized egg during If an egg is not fertilized, the lining sloughs away, a period.
