Menstruation is a normal, healthy process that a woman's body goes through from her early teen years until menopause. As part of your monthly menstrual cycle, your uterus grows a new lining (the endometrium) to prepare for the possibility of a fertilized egg. If a fertilized egg does not implant in the lining, then the uterus will shed the endometrium; this shedding initiates menstrual bleeding, otherwise known as your period.
The menstrual cycle normally lasts from 21 to 35 days - although teens and women in their 40s may have longer, irregular cycles up to 45 days. If you are nearing menopause, you can expect that the time between your periods will probably get longer, and eventually, stop. Other signs of approaching menopause are hot flashes and mood changes.
If you are you are not approaching menopause and your period becomes irregular it could be a sign of stress, dramatic weight loss, or conversely, sudden weight gain. All of these conditions can affect your body's hormone levels and may cause changes in the length of your cycle. Medications such as antidepressants can also be a common, harmless cause of cycle changes.
Certain endocrine conditions such as polycystic ovaries and thyroid disorders can also cause irregular cycles; these disorders should be checked out by a specialist.
A normal period usually lasts about 3-5 days: anything longer than 7 days is considered prolonged bleeding.
Flow is generally heavier during the beginning of your period and gradually gets lighter. It is normal to see small blood clots in your period; they may just be small pieces of the endometrium. If the clots are larger than a quarter, however, this could be a sign of abnormal bleeding. Similarly, if you have to change your pad or tampon more than 5 times a day or if you are soaking through every hour, your bleeding is excessive and could be an abnormal sign.
Fibroids are benign tumors in the uterus and are a very common cause of abnormally heavy bleeding. More rarely, a bleeding disorder can cause heavy flow when your body cannot clot blood effectively.
Spotting, or light breakthrough bleeding, is also a normal variant and is very common in women on low dose birth control pills. If you are having light, breakthrough bleeding in the middle of your cycle it is probably nothing to worry about, although in some cases, it can be a sign of cervical polyps.
Lighter flow is also normal for women on oral birth control pills. If you miss your period altogether, the first thing to rule out is pregnancy. Once you have done that, another possible cause for a missed period is anovulation, which simply means you did not ovulate that month. It's possible that your next period may be heavier or longer if you have skipped a period in between.
For most women, incidental anovulation is normal and not a cause for worry. Some women simply have a more sensitive endocrine feedback system so that changes in stress, weight, and other factors cause shifts in their menstrual cycle.
For many women, cramps and bloating are the most uncomfortable parts of a menstrual period. Cramps are the result of chemicals called prostaglandins, which are released in the uterus and cause contractions as you shed the uterine lining. The best defense against painful cramps is to take an over the counter anti-inflammatory (ibuprofen, aspirin) to cut down on the production of prostaglandins.
If your cramps are very severe or disabling, it could be a sign of something more serious, such as endometriosis, a condition that can affect up to 10% of women. Endometriosis means that you may have uterine tissue growing outside the uterus, typically in the pelvic area, a situation that can cause severe cramps and pain.
Remember, different women will have subtle differences in their menstrual cycle depending on their age, weight, and other important factors. The key is to know what's normal for your own body so that you are better able to detect changes that could signal a more serious problem.