Why Am I Passing Blood Clots During My Period?
Seeing blood clots during your period can be surprising—and sometimes a little alarming. The good news is that small menstrual blood clots are often completely normal, especially on heavier flow days.
Understanding what’s happening during your menstrual cycle can help you recognize what’s expected, when to seek medical care, and how your period serves as an important indicator of your overall health. In fact, your menstrual cycle is often considered a vital sign because it provides important insight into your reproductive and overall health.
Why Do Blood Clots Form During Your Period?
Each month, your uterus builds a thick lining called the endometrium in preparation for a possible pregnancy.
If pregnancy doesn’t occur, hormone levels—particularly progesterone—drop. This causes the tiny blood vessels supplying the uterine lining to narrow, reducing blood flow. As the lining breaks down, your uterus contracts to help shed it.
Your menstrual flow is made up of blood, endometrial (uterine lining) tissue, cervical mucus, and other cells from the uterine lining.
Blood naturally clots to help prevent excessive bleeding whenever a blood vessel is injured. During heavier periods, blood may collect in the uterus or vagina before leaving the body, allowing small clots to form.
This is why it’s common to notice blood clots during your heaviest flow days.
What Do Normal Menstrual Blood Clots Look Like?
Normal menstrual blood clots are typically:
- Smaller than a nickel
- Bright red or dark red
- Soft or jelly-like
- Most common during the first few days of a heavier period
These clots may consist of:
- Blood
- Pieces of the uterine lining
- A combination of both
Because they look very similar, it’s often impossible to distinguish between them.
Why Is My Period Blood Different Colors?
The color of your menstrual blood depends on how long it has remained in the uterus or vagina before leaving your body.
Fresh blood is often bright red, while blood that has taken longer to leave the body may appear dark red or brown. It’s completely normal to notice different shades throughout your period.
Want to learn more? Read our blog, Period Blood Colors Explained.
Why Do Some Periods Have More Blood Clots Than Others?
Every menstrual cycle is different, and the amount of bleeding and clotting can vary from month to month.
Several factors can contribute to heavier bleeding and more noticeable blood clots.
Hormone Changes
Estrogen and progesterone influence how thick your uterine lining becomes each month. A thicker lining often means:
- Heavier bleeding
- More tissue to shed
- More noticeable blood clots
Uterine Fibroids
Fibroids are common, noncancerous growths in the muscle of the uterus that can cause:
- Heavier periods
- Increased clotting
- Blood to pool in the uterus before leaving the body
Pregnancy Loss
Even an early miscarriage can result in significantly heavier bleeding and larger blood clots than a typical menstrual period.
Do All Women Experience the Same Amount of Clotting?
No. Every person’s menstrual cycle is unique.
Some people naturally experience more clotting than others, while certain medical conditions—such as bleeding disorders or uterine fibroids—can also affect the amount of bleeding and clotting during a period.
If you’ve always had unusually heavy periods or notice a significant change in your menstrual flow or clotting, it’s a good idea to talk with a healthcare provider. They can help determine whether an underlying condition may be contributing to your symptoms.
When Should I See a Doctor About Menstrual Blood Clots?
Some menstrual clotting is completely normal.
However, you should schedule an appointment with a healthcare provider if you experience:
- Blood clots larger than a nickel
- Bleeding that soaks through one or more pads or tampons every hour for three consecutive hours
- Periods lasting longer than seven days
- Menstrual cycles shorter than 21 days or longer than 35 days
- Bleeding between periods
- Unpredictable menstrual cycles
- Menstrual cramps that interfere with daily life
- A noticeable change in your usual menstrual pattern
Heavy or irregular periods can sometimes be caused by conditions such as fibroids, hormonal imbalances, adenomyosis, bleeding disorders, or other gynecologic conditions. Your provider can help determine the underlying cause and recommend treatment options.
When Is Heavy Menstrual Bleeding an Emergency?
Seek emergency medical care immediately if you experience:
- Soaking through multiple pads or tampons in one hour for more than one hour
- Passing blood clots larger than a quarter or about the size of a golf ball
- Severe abdominal or pelvic pain with heavy bleeding
- Feeling faint, dizzy, or lightheaded
- Shortness of breath
- Pale skin
- A rapid heartbeat
- Heavy bleeding during pregnancy
These symptoms may indicate significant blood loss and should be evaluated as soon as possible.
The Bottom Line
Passing small blood clots during your period is often a normal part of menstruation, especially during heavier flow days. Knowing what’s typical for your body can help you recognize when something changes.
If your bleeding becomes significantly heavier, your periods last longer than usual, or your symptoms begin interfering with your daily life, it’s time to talk with a healthcare provider.
At Diana Health, we believe your period is more than just a monthly cycle—it’s an important window into your overall health. We’re here to answer your questions, evaluate concerning symptoms, and help you feel confident in your care.
If you’re experiencing heavy periods, passing large blood clots, or have concerns about your menstrual cycle, we’re here to help. Schedule an appointment with a Diana Health provider to get personalized, compassionate care.
