Home Who We Are Let's Talk Legal Stuff Blank


What Happens During My Period
Recognizing Irregularities
Other Resources

Getting your period is not only an indication that a girl is entering womanhood, but it is also a physiological indication that your body is capable of having a baby.  From the moment a girl gets her first period, usually around age 13, but sometimes as early as age 8 and as late as age 19, she will experience many physical as well as emotional changes.  At first these changes might not be so comfortable or even welcomed, but whether we like it or not, they're here to stay for a while, so let's make the best of it!

The first step is getting to know your body and understanding what is happening during your menstrual cycle:

Your period is usually on a cycle of 28 days, though different women's cycles vary by a few days.  The day you start bleeding is considered the first day of your cycle, meaning that 28 days or so from then you will bleed again and then your cycle will start all over.  In other words, from the first day of one period until the first day of the next is your menstrual cycle.  You will have your menstrual cycle until you begin menopause.

[ To Top ]
What Happens During My Period?[1]

A woman's reproductive system is largely controlled by two powerful hormones -- estrogen and progesterone.  Women have two ovaries that store thousands of microscopic eggs.  Girls are born with all the eggs they will ever have, but these eggs do not fully mature until they are ready to be released from an ovary. 

Preparation for release of an egg from an ovary is triggered by production of high levels of these two hormones by the ovaries. 

These hormones trigger certain changes in the endometrium, the lining of the uterus. 

In preparation for releasing an egg, the lining of the uterus begins to thicken and build up a blood-rich lining for a possible pregnancy. 

Estrogen then stimulates the ovaries to release a ripe egg, also referred to as ovum. The release of the egg is called ovulation, and it occurs at the midpoint in the cycle - usually day 14 of a 28-day cycle, for example. An egg is released from alternating ovaries once a month. 

Women don't usually feel their bodies ovulating, but some might notice mild cramping or experience PMS-like symptoms.  Other women actually feel at their best during ovulation. It's different for different people. Sometimes a woman will have some spotting of blood for a day or two after ovulation. This is normal, but it is not her period.

There are usually 14 - 16 days from ovulation to the beginning of a woman's period. However, the time from the beginning of your period to the next ovulation may vary -- it may be less than one week or it may be two weeks or more.  From the ovary, the egg moves into one of the fallopian tubes.

Once in the fallopian tube, one of two things can happen to the egg:

  1. It can get fertilized by a male's sperm
  2. It breaks down if not fertilized

If a male's sperm fertilizes the egg, the fertilized egg will take about 5 days to travel down the fallopian tube and attach to the thick, blood-rich lining of the uterus where it will nest and develop into a zygote.  This is the beginning of a pregnancy.

If it's not fertilized, the egg begins to fall apart, the estrogen and progesterone levels drop, and the uterine lining breaks down and is shed - this bleeding is what's known as your "period". The lining sheds and flows out of your uterus, through your cervix, through your vagina, and out of your body.

Periods usually last from three to seven days. The flow usually starts light. It can get heavy for two or three days then get light again until it stops. It often starts off a rusty color, and then gets redder. It can then lighten up to a rust color again until it stops.

If you keep track of when your period comes each month (mark it on a calendar), it will help you to figure out what your own personal cycle is. If you find that your cycle is fairly regular, it can help you predict when you'll get your period. But remember, your body is not a machine - your cycle can shift and change without warning. 

[ To Top ]
Knowing What's Regular and What's Irregular About Your Cycle

Cramping and Dysmenorrhea[2]

More than half of menstruating women experience cramp-like pain during their periods. Cramps are usually felt in the pelvic area and lower abdomen, but can radiate to the lower back or down the legs.

Mechanically, cramps are like labor pains. Just as the uterus contracts to open up the cervix (neck of the uterus) and push out a baby, it contracts to expel menstrual blood. Often, after several years of menstruating or after childbirth, the cervical opening enlarges. The uterus doesn't have to contract as much to discharge the menstrual flow, so there is less cramping.

Menstrual pain may also come from the bleeding process itself. When the uterine lining separates from the wall, it releases chemicals called prostaglandins. Prostaglandins cause blood vessels to narrow, impeding the supply of oxygen to the uterus. Just as the pain of a heart attack comes from insufficient blood to the muscles of the heart, too little blood to the uterine muscle might cause the pain of menstrual cramps.

Menstrual pain can have other causes, although these are rare among younger women. They include:

  • Tumors
  • Fibroids
  • Fallopian tube infection
  • Endometriosis

Sometimes, simple measures are all that's needed to feel better. Cutting down on salt might help reduce fluid buildup, and support hose may alleviate swelling in the legs or ankles. Crawling into bed for some extra rest or sleep is one way to deal with fatigue, and using a heating pad or hot water bottle eases cramps for some. Exercising also helps reduce pain in many young women, and may lift a blue mood as well.

If symptoms interfere with work, school or sleep, the American College of Obstetricians and Gynecologists recommends seeing a doctor, who may suggest taking one or more medicines. Certain anti-inflammatory drugs called NSAIDs (an abbreviation for nonsteroidal anti-inflammatory drugs) inhibit prostaglandin production, thus easing cramps. Prescription NSAIDs include naproxen (Naprosyn, Anaprox), ibuprofen (Motrin, IBU), indomethacin (Indocin), and mefenamic acid (Ponstel).

If needed, your doctor may consider prescribing other pain medications or diuretics, or even oral contraceptives. It turns out that a possible positive side effect of birth control pills is relief of menstrual cramps.

Over-the-counter acetaminophen products like Tylenol, Datril, and aspirin-free Anacin also may help menstrual pain. It takes time for pain relievers to work, so it's best to take them before the pain gets bad and continue for one or two days, as needed.

Some 20 to 40 percent of menstruating women have experienced symptoms of PMS, or premenstrual syndrome.[3]  Additionally, nearly 5% will experience premenstrual dysphoric disorder (PMDD), a syndrome with specific symptoms that can interfere with work and interpersonal relationships during a certain time of the month.[4]  Starting anywhere from mid-cycle to a few days before menstruation begins, women with PMS may have one or all of a virtual laundry list of physical and emotional symptoms. They include:

  • Breast swelling and tenderness
  • Fluid retention
  • Increased thirst or appetite
  • Craving for sweets and salty foods
  • Headaches
  • Anxiety
  • Restlessness
  • Irritability
  • Depression
  • Hostility
  • Loss of self confidence

Experts say PMS doesn't usually affect teenagers. Its incidence increases with age and is more prevalent when women are in their 30s and 40s.

[ To Top ]

Dysmenorrhea is severely painful menstruation that can interfere with a young woman's ability to attend school or study or sleep.  This type of menstrual pain should be discussed with a doctor.[6]

There are two kinds of painful menses--primary and secondary dysmenorrhea--and it is very important to distinguish between them so both are treated properly.

Primary dysmenorrhea - usually starts within three years of the onset of menstruation and lasts one or two days each month. While this type of menstrual pain may lessen for some women as they grow older or after the birth of children, it also can continue until menopause.

Secondary dysmenorrhea - is menstrual pain caused by disease such as pelvic inflammatory disease, endometriosis (abnormalities in the lining of the uterus), or uterine fibroids link to fibroids page (nonmalignant growths). A hint that the disease might be the cause of menstrual pain is if the pain also occurs during intercourse or during other parts of the menstrual cycle.

Primary dysmenorrhea is a result of the normal production of prostaglandins--chemical substances that are made by cells in the lining of the uterus. (Prostaglandins are also produced elsewhere throughout the body.) The lining of the uterus--which has built up and thickened during the early stages of the menstrual cycle--breaks up and is sloughed off at the end of the cycle and releases prostaglandins. The prostaglandins, in turn, make the uterus contract more strongly than at any other time of the cycle. They can even cause it to contract so much that the blood supply is cut off temporarily, depriving the uterine muscle of oxygen and thus causing pain. Women who suffer painful contractions may be producing excessive amounts of prostaglandins.

The cramps themselves help push out the menstrual discharge. Because the cervical opening is often widened after childbirth or years of menstruation, cramps may lessen in severity later in life.

Most women describe their menstrual cramps as a dull aching or a pressure low in the abdomen. The pains may wax and wane, remain constant, or be so severe that they cause nausea, vomiting, diarrhea, backache, sweating, and an ache that spreads to the hips, lower back, and thighs.

[ To Top ]

Regular Flow and Amenorrhea[7]

Many young women have very irregular periods for the first couple years of menstruation.  Young women also don't ovulate regularly every month, which makes it difficult to know you are ovulating. Therefore, a woman should assume that she could get pregnant every month, even if she has irregular periods.

Eventually, periods usually become regular, but even when they do, a missed or late period once a year--especially at a stressful time--is considered normal. Also, just as strenuous exercise and eating disorders can delay the onset of menstruation, they can also cause previously regular menstrual cycles to become irregular or stop completely.

Amenorrhea[8] , or the absence of periods, is divided into two categories:

  • Primary amenorrhea Ð menstruation has never taken place. It fails to occur at puberty.
  • Secondary amenorrhea -- menstruation starts but then stops. The absence of menstruation during pregnancy is a form of physiologic secondary amenorrhea (physiologic in the sense that it is completely normal and is not caused by anything harmful). Amenorrhea during lactation is another type of physiologic secondary amenorrhea.

Secondary Amenorrhea[9]

A period that is 2-3 weeks overdue should be investigated to rule out pregnancy. Stress and changes in environment are responsible for most cases of missed periods in adolescents. Young women are especially likely to have irregular periods with fevers, emotional upset, weight loss, changes in environment, or increased participation in competitive athletics.  Amenorrhea is also a symptom of anorexia nervosa. If you have signs of amenorrhea, contact a doctor to make sure that it is normal and to prevent further complications.

[ To Top ]

[1] Adapted from:, and from







[8] Adapted from:

[9] Adapted from:

[ To Top ]
This website is an information resource center and does not provide medical advice.
Information from website should not be a substitute
for medical advice from a health care professional.