Understanding Irregular Periods

Having irregular periods can be triggered by many different things, including lifestyle choices, age, side-effects of certain medications, and current medical conditions. The most important thing you can do is to learn to recognize signs of an irregular period and know when it’s important to speak with your gynecologist—a doctor who focuses on women’s reproductive health. Gynecologists also work with women of all ages, starting from prepuberty (age 11) and continuing throughout life.

As you may know, the average menstrual cycle results in a period every 28 days, but for many women, their cycle isn’t always the same. In general, though, most women have a period anywhere between 21 to 35 days, which lasts about 2 to 7 days. However, menstrual bleeding is considered irregular if the period is early, missed, late, or occurs more frequently.

How do you know if you’re experiencing irregular periods? By paying close attention to your cycle and keeping track. From the first day of your previous period, count the number of days that pass until the first day of your next period. Write this information down for three months. At the end of three months, if the number of days vary greatly (more than 4 days) between stopping and starting your period, then you have an irregular period. There are many free apps now available on smart phones to help you keep track of your periods.


In a few cases, changes in a menstrual period are normal, especially at different ages in a woman’s life. For example, when teenagers first start having periods, their menstrual cycles may not always be on the same schedule every month, which is okay for at least a couple of years. Also, a change in a woman’s menstrual cycle is one of the first clues they’re in perimenopause, which literally means the time “around” menopause. Perimenopause is a term used to describe the beginning of the estrogen decline leading to menopause. In the beginning, periods may come a week early or a week late. The more common that pattern becomes, the greater the likelihood a woman is entering perimenopause.

However, if you’re experiencing irregular periods unrelated to age, the following could be some of the most common causes, which may be signaling a potential problem.


People who exercise too much, and even athletes, can experience irregular periods because the timing of menstrual bleeding is thrown off kilter and, in some cases, may even cause periods to stop completely. In addition, if a woman is underweight, partakes in extreme dieting, or has an eating disorder, these can also cause periods to be irregular or stop.


Chronic stress or even short-term anxiety can cause women to miss a period or have spotting in between periods. One reason for this is because stress can greatly affect hormone balances. Misusing birth control pills may also cause occasional spotting.


Irregular periods can also signal the onset of several diseases, such as endometrial cancer, hyperplasia (precancer), and thyroid disorders—because blood levels of the thyroid hormone are too low or too high. Other health conditions that may cause irregular periods include sexually transmitted diseases, diabetes, fibroids, and endometriosis.

If you notice excessive bleeding throughout the month that is becoming heavier or longer, you should speak to your gynecologist or physician as soon as possible. Like anything, treatments are better if the onset of potentially serious illness is detected early.


  • Heavy bleeding. If you’re soaking your pad or tampon every hour or two, that’s excessive—especially if it goes on more than a few days.
  • Skipping periods. Missing one period isn’t usually a big deal. But if you skip two periods or it has been three months or more since your last period, and you haven’t gotten it again, that warrants a checkup. However, if you miss a period and have abdominal pain, don’t wait to speak with a gynecologist, as this could be very serious.
  • You are having problems with your period, like a lot of pain, bleeding heavily, or bleeding for longer than usual, or it has stopped coming regularly.
  • You are having sex and missed your period.
  • You have not gotten your period by the age of 15 or within three years of when your breasts started to grow.
  • You have stomach pain, fever, and/or fluid coming from your vagina that is yellow, gray, or green with a strong smell—all of which are possible signs of a serious condition called pelvic inflammatory disease (PID) that needs immediate treatment.

You’ve had your period for two years and it’s still not regular or comes more than once a month.


No matter what stage you’re at in life, seeing a gynecologist is one of the most important things you can do for your well-being. Heidi S. Weaver, MD, is an obstetrician-gynecologist (Ob-Gyn) at the Bingham Memorial Women’s Center. As an Ob-Gyn, Dr. Weaver is qualified to care for all women’s healthcare needs. She also understands the challenges facing today’s women and encourages patients to be open with her so she can provide the best care for them. Dr. Weaver is always welcoming new patients. To schedule a consultation with her in Blackfoot, please call (208) 782-3900.

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