Why is My Period Lasting So Long?

2023-06-28T15:25:36-06:00July 14th, 2022|

Written by: Dr. Annie Martin, reproductive endocrinology and infertility specialist at CCRM Fertility of Northern Virginia

When it comes to the menstrual cycle, AKA your period, there is a lot of variability in what is considered to be “normal.” Periods can last a few days and be very light, or they could last a week with heavy bleeding. However, up to 14% of people experience heavy, painful, or irregular periods.

By keeping track of your menstrual cycle, you can figure out what’s normal for you, as well as help identify concerns that should be addressed. We’ll explain nine possible reasons why your period is lasting so long.

How Long Should Periods Last?

First, it’s important to know how long your period should last. On average, the menstrual cycle is every 21 to 35 days and during your period, bleeding can last 2 to 7 days. But what is normal for one person might not be for another. However, heavier or longer periods can increase your chances of anemia.

Menorrhagia is when your period lasts longer than a week or it’s heavier than what’s considered normal. Heavy bleeding means you are soaking through a pad or tampon after less than 2 hours, or you are passing clots that are larger than a quarter. Menorrhagia can increase your chances of anemia, a condition where your red blood cells don’t have the capacity to carry oxygen to various tissues throughout your body.

If you’ve had heavy or prolonged bleeding, talk with your doctor to see if you should be tested for anemia. Supplementing or eating high-iron foods such as red meat, spinach, and poultry, or taking an iron supplement may help.

What Can Cause Long Periods?

There are several reasons that could explain why your period is heavy or is lasting longer than usual.

Hormone and ovulation changes

Your hormones regulate the menstrual cycle, so when there is an imbalance, it can cause changes in bleeding. Hormone imbalances can be caused by certain health conditions including:

Both the onset of puberty and the transition to menopause are times where hormonal changes are common. Therefore, it is very normal to experience irregular or prolonged periods during these points in your reproductive life.

Blood-Thinning Medications

Blood thinners are medications that prevent blood clots in your vessels. There are two different types of blood thinners: anticoagulants and antiplatelets. Anticoagulants, such as enoxaparin (Lovenox), slow the body’s clotting process. About 70% of women who are on an oral anticoagulant have heavy menstrual bleeding. Antiplatelets, such as aspirin, make your body’s platelets slippery and prevents them from forming a clot.

While these medications help to prevent blockages in the blood vessels and strokes, they can cause heavy and prolonged menstrual bleeding.

Uterine fibroids or polyps

Fibroids are noncancerous growths made up of muscle and connective tissue from the wall of the uterus. They can cause pain and heavy menstrual bleeding because they don’t allow the uterus to contract properly (these are the cramps you can feel). Fibroids range in size from an apple seed to the size of a grapefruit and sometimes larger.

Polyps are growths as well, but they attach themselves in the inner lining of the uterus, known as the endometrium, by a stalk. Polyps are made up of endometrial tissue and can also cause irregular or heavy periods.


Normally, endometrial tissue lines the inside of the uterus. Sometimes, endometrial-like tissue grows into the muscle of the uterus causing thickening, a condition known as adenomyosis. This endometrial tissue sheds during your period just as the tissue lining the uterus. This causes heavy and painful periods.

According to a 2020 analysis, in women who had symptoms of adenomyosis, 20% to 88.8% had heavy and painful periods. Researchers also noted the average age of diagnosis is 32 to 38 years. Adenomyosis can be challenging to diagnose because there isn’t a standard criteria used by doctors to make a diagnosis.

Thyroid condition

The thyroid is the gland that produces thyroid hormone and is located at the base of your neck. About 1 in 8 women will have a problem with their thyroid in their life. In addition to regulating your metabolism, the thyroid helps to regulate your menstrual cycle. Producing too much or too little thyroid hormone can cause you to have heavier or lighter periods than normal, or cause them to become irregular.

Bleeding condition

Blood clots that normally form after an injury do so in response to platelets, a type of blood cell, and proteins called clotting factors. If your blood doesn’t clot properly, or your body doesn’t make enough platelets or clotting factors, you can have prolonged and/or heavy periods.

The most common type of bleeding disorder in women is Von Willebrand disease (VWD). Both men and women can have VWD, but women tend to be more symptomatic due the impact VWD can have on the menstrual cycle. Most often, bleeding disorders are inherited, meaning they run in the family.


Having a higher body weight can affect the balance of your reproductive hormones, which can cause you to have changes in your period.

According to a 2021 study in the Journal of Endocrinology, there is an association between a higher body weight and heavy menstrual bleeding. It’s thought to be due to an increase in inflammation in the uterine lining, which can affect how well the tissue repairs itself after menstruation.

Pelvic inflammatory disease

Pelvic inflammatory disease (PID) is an infection of the upper genital tract that occurs when bacteria spread from sexual contact travels from the vagina to the uterus, fallopian tubes, ovaries and pelvis. You may not even be aware you have PID until you have fertility challenges or pelvic pain that doesn’t go away but it can also result in irregularities in your menstrual cycle.


Certain cancers, especially ones affecting the reproductive system, might cause heavy or prolonged periods. Heavy bleeding can be a sign of endometrial cancer. Though endometrial cancer tends to affect women in their mid-60s who have already gone through menopause, women who do not ovulate regularly (for instance, women with PCOS) as well as women with obesity, are at higher risk for endometrial cancer. Endometrial hyperplasia is the precursor to endometrial cancer which can also cause irregular or heavy bleeding.

When It’s Time to See A Doctor

Signs that you should contact your doctor include:

  • Menstrual bleeding that last longer than 7 days
  • Passing clots larger than a quarter
  • Changing pads or tampons more than every hour
  • Changing pads in the middle of the night
  • Feeling more tired than usual or feeling lightheaded

If you suspect your period is lasting longer than usual or you have heavy bleeding with your periods, don’t hesitate to contact your doctor. It’s important to find the cause of longer or heavier periods to not only rule out more concerning medical conditions but to improve your overall quality of life.

About CCRM

CCRM is one of the industry's leading pioneers in fertility science, research and advancement, offering access to a national network of award-winning physicians, a full suite of fertility services, innovative technology and cutting-edge labs.

Book your appointment Call