An elevated D-dimer during menstruation or otherwise is not normal, and it is usually discovered after a clot has developed and is in the process of breaking down. Fibrin D-dimer is the degradation product from cross-linked fibrin, a marker of intravascular thrombogenesis. Menstruation is associated with the activation of coagulation and fibrinolytic pathways.

If you have significant formation and breakdown of a blood clot in your body, it can signify that your D-dimer may be elevated. On the contrary, a negative D-dimer test indicates that a blood clot is highly unlikely. 

Women in menstruation can experience discharge of blood clots. Menstrual clots are gel-like blobs of coagulated blood, tissue, and blood ejected from the uterus during menstruation. They can vary in color from bright to dark red.

Normal vs. Abnormal Clots

If the clots are small and only occasional, it is usually nothing to worry about. Unlike clots developed in your veins, menstrual clots themselves are not harmful. However, regularly passing large clots during your menses could signal a medical condition that requires examination.

Normal clots have the following characteristics:

  • They are smaller than a quarter
  • They only occur occasionally, usually toward the beginning of your menstrual cycle
  • They appear bright or dark red

On the other hand, abnormal clots are larger than a quarter and occur more frequently. See your physician if you bear heavy menstrual bleeding or clots bigger than a quarter. Menstrual bleeding is considered heavy if you need to change your tampon or menstrual pad every two hours.

Abnormal clotting does not always happen due to menses. It can also develop in a vein, indicating elevated d-dimer levels. 

Causes of Menstrual Clots

Most women of childbearing age will experience menses every 28 to 35 days. They shed their uterine lining called the endometrium.

The endometrium grows and thickens throughout the month as a reaction to estrogen, a female hormone. Its goal is to support a fertilized egg. However, if pregnancy does not occur, other hormonal events signal the lining to shed. It is called menstruation, also known as a menstrual period, period, or menses.

When the lining is shed, it combines with:

  • Blood
  • Blood byproducts
  • Mucus
  • Tissue

This combination is then discharged from the uterus through the cervix and out the vagina. As the uterine lining sheds, it gathers in the bottom of the uterus, lingering for the cervix to contract and eject its contents. The body releases anticoagulants to thin the material and pass it more freely to break down the thickened blood and tissue. However, menstrual clots are released when the blood flow outpaces the body’s capacity to make anticoagulants.

The blood clot is commonly formed during heavy blood flow days. For many women, heavy flow days usually occur at the beginning of a period and are short-lived. The menses flow is considered normal if menstrual bleeding lasts 4 to 5 days and produces 2 to 3 tablespoons of blood or less.

Excessive bleeding and clot formation are extended for women with heavier flows. The research found that one-third of women have so heavy they soak through a pad or tampon every hour for several hours.

Underlying Causes for Menstrual Clots

Following are some of the underlying causes of menstrual clots:

Uterine Obstructions

Conditions that enlarge the uterus can put extra pressure on the uterine wall, increasing menstrual bleeding and clots. Obstructions can also meddle with the uterus’s capacity to contract. When the uterus is not properly contracting, blood can pool and thicken inside the uterine cavity and form clots.

1-Uterine obstructions can be caused by:

  • Fibroids
  • Endometriosis
  • Adenomyosis
  • Cancerous tumors


Fibroids are generally noncancerous, muscular tumors growing inside the uterine wall. Besides heavy menstrual bleeding, they can also produce:

  • Irregular menstrual bleeding
  • Lower back pain
  • Pain during sex
  • A protruding belly
  • Fertility issues

About 80% of women can form it by the time they are 50. The reason is unknown, but genetics and the female hormones estrogen and progesterone likely play a significant role in their development.


Endometriosis is a condition in which cells resemble the uterus lining called endometrial cells and grow outside the uterus and into the reproductive tract. It can produce:

  • Painful, crampy periods
  • Nausea, vomiting, and diarrhea around the time of your period
  • discomfort during sex
  • Infertility
  • Pelvic pain
  • Abnormal bleeding, which may or may not include clotting


Adenomyosis happens when the uterine lining, for unspecified reasons, grows into the uterine wall, causing the uterus to enlarge and thicken.

In addition to extended, heavy bleeding, this common condition can force the uterus to grow two to three times its standard size.

5- Cancer

Although it is rare, cancerous tumors of the uterus and cervix can lead to heavy menstrual bleeding.

These are some of the medical causes that can form clots. The elevated d-dimer during menstruation may not always be the culprit of forming thick blood clots. It is always better to consult a professional healthcare provider for your condition. You can book an appointment with the best Gynecologists in Karachi through Marham. 


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