March 23, 2023

Why Does My Menstrual Cycle Last Longer?

woman concerned about her long menstrual cycle

The average menstrual cycle is 21 to 35 days, with an average of 28 days. But it’s important to note that this is the average. Both the time between periods and the length of a period can vary significantly. 


However, if you’re used to a particular rhythm, and you find your period is longer than usual on one or more occasions, it’s understandable to wonder what (if anything) is causing the change. 


Period Longer Than Usual? Here Are 12 Possible Causes.

Several things can cause your period to be prolonged. Some are actions you take, and others are medical conditions. Some of the most common causes of an extended period are:


  1. Medications. Over-the-counter medications like aspirin or anti-inflammatory drugs can affect your period length, making it longer or shorter respectively. Prescription medications can also cause changes in your periods, making them longer, shorter, or irregular. 
  2. Hormonal birth control. The various types of hormonal contraceptives (pills, patches, IUDs, shots, etc.) can affect your cycle duration and flow. If you’ve recently started using hormonal birth control or changed to a new type and have concerns about your periods, you should talk with your doctor. 
  3. Abortion. Your first period after an abortion (medical or surgical) may be different than usual. You may also experience post-procedure bleeding that isn’t caused by your period. In addition, pregnancy hormones are still present in your system for a few weeks after an abortion and can affect your cycle. 
  4. “Morning after” pill. Emergency contraception can affect your first period after you use it. It can cause a period that’s early/late, heavier/lighter, shorter/longer, and more/less painful. You may also experience spotting before your next period. 
  5. Miscarriage. Miscarriages can occur even before you know you’re pregnant, causing period-like bleeding that’s heavier and lasts longer than your typical period.
  6. Hypothyroidism. If your thyroid starts producing less thyroid hormone, you can experience changes to your cycle, including heavier, longer, or more frequent periods. They may also stop entirely.
  7. Obesity. Higher body weight can affect reproductive hormones and cause periods to be heavier or longer. 
  8. Uterine polyps or fibroids. Growths on the uterus lining can cause heavier or more extended periods. These are more common in those 35 to 50 years old and those in perimenopause.
  9. Endometriosis. If uterine lining tissue grows outside the uterus, the condition is called endometriosis. It can cause periods to be longer and with heavier flows. 
  10. Adenomyosis. In this condition, uterine lining-like tissue grows into the uterine muscle. It can affect the length and flow of your periods. 
  11. Pelvic inflammatory disease (PID). Caused by bacteria spread by sexual contact, this infection of the upper genital tract can produce changes in your menstrual cycle. 
  12. Cancer. In particular, cancers of the reproductive system can cause heavy or prolonged periods. 

When to Contact Your Doctor About Longer Periods

Because there are many possible causes of menstrual cycle changes, it’s crucial not to jump to conclusions. If your period lasts longer than a week, talk with your doctor. They can diagnose the cause and recommend treatment if needed. 


Learn About Baptist Health Women’s Services

Don’t let longer periods or any changes to your menstrual cycle cause you stress. Take advantage of our outstanding women’s services at Baptist Health and connect with a knowledgeable, caring professional who can help you understand and address any issues you experience.

Learn More.