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What Are the Causes of Irregular Periods?

What Are the Causes of Irregular Periods?

Irregular and missed periods are common menstrual irregularities among women of all ages, especially during menopause. The hormonal imbalance of the body during this change often means that periods come earlier or later than expected. There is no definition for what a “normal” period is, but menstruation typically occurs every 25 to 31 days and lasts for five days.

During this time it is more difficult, but still possible, to get pregnant. Some of the main causes of irregular periods are listed below.

Hormonal Changes

A woman's menstruation is controlled through many hormones, including estrogen and progesterone. They affect the menstrual cycle in multiple ways:


Prior to ovulation, estrogen thickens the lining of the uterine walls. Since estrogen levels tend to become unpredictable during menopause, this can lead to irregular shedding of the lining and heavier bleeding.


Following ovulation, progesterone is responsible for shedding the uterine contents if there is no fertilization. It controls duration and intensity of menstrual bleeding. When there is a hormonal imbalance, irregular periods occur.

What Are the Causes of Irregular Periods?

As we can see, the decrease in hormones that comes with menopause is one of the main reasons irregular periods occur. The wild fluctuations just make it worse, but there are other causes of irregular periods.

Health Conditions

There are many health problems and conditions that lead to irregular periods. These health conditions include:

  • Anemia
  • Thyroid dysfunction
  • Polycystic ovary syndrome (PCOS)
  • Irritable bowel syndrome (IBS)
  • Uterine abnormalities
  • Tuberculosis
  • Liver disease
  • Diabetes
  • Cancer


Your lifestyle is an integral part of how well you can live your life. There are many triggers of lifestyle reasons for irregular periods and these are:

What Are the Causes of Irregular Periods?
  • Stress
  • Poor nutrition
  • Over-exercise
  • Caffeine and alcohol excessive consumption
  • Smoking
  • Drugs intake
  • Poor nutrition
  • Weight gain or loss
  • Breast feeding
  • Certain medications

What to Do Next?

Throughout the life of a woman she has an average of 500 menstrual cycles and this increases the chances of irregular periods. The causes of irregular periods need to be correlated with the symptoms of this problem. Click on articles below for more information about irregular periods.

Long Menstrual Cycles

Long menstrual cycles can be frustrating, and are commonly experienced by women going through menopause. Click here to learn more.

Constant Irregular Periods

Irregular periods are one of the earliest signs that a woman is approaching menopause. They can be caused by a range of medical conditions.

Irregular Periods and Birth Control Pills

The hormonal changes brought by birth control pills can sometimes cause irregular periods. Click here to learn more about managing irregular periods.

  • BMJ Group. "Menopause: What is it?" Patient Leaflet. 2007.
  • Hutchinson, Susan, M.D. "The Stages of a Woman's Life: Menstruation, Pregnancy, Nursing, Perimenopause, Menopause." November 2007.
  • Love, Susan, M.D. Menopause and Hormone Book. New York: Three Rivers Press, 2003.