What is Period Blood Clots? Symptoms, Reasons and Health Risks

What Are Period Blood Clots?

Period blood clots are thickened lumps of menstrual blood that form when blood coagulates before leaving the uterus.

During menstruation, the body sheds the uterine lining. This lining mixes with blood and passes through the cervix and vagina. When menstrual flow is heavy or moves more slowly, natural clotting agents in the blood can cause clots to form before the blood exits the body.

These clots often appear dark red or deep brown and can vary in size and texture.

What Does Normal Period Blood Clotting Look Like?

Small, occasional blood clots; especially during heavier flow days, are usually normal.

Normal menstrual clots typically:

• Occur on the heaviest days of bleeding
• Are dark red or maroon in colour
• Do not cause severe pain or sudden changes in bleeding

When Are Period Blood Clots Considered Heavy or Abnormal?

Period blood clots can appear occasionally, especially on heavier days and this is often normal. They may need attention when they begin to differ from what’s typical for you.

You may want to look closer if:

• Period blood clots are larger than usual, especially bigger than a pea
• Clots appear repeatedly throughout the period, not just once or twice
• There is a sudden change in the size or number of period blood clots from one cycle to the next
• Periods last longer than seven days or feel harder to manage than before
• Bleeding is very heavy or leaves you feeling unusually tired or weak

Period blood clots are not always a sign of a health problem. However, noticing changes over time can help you decide when it may be worth seeking medical advice.

What Symptoms May Occur Alongside Period Blood Clots?

Period blood clots can occur on their own or alongside other menstrual symptoms, depending on the cause.

You may experience:

• Lower abdominal or pelvic pain
• Fatigue or weakness
• Dizziness during menstruation
• Anaemia-related symptoms such as shortness of breath
• Severe cramping that limits daily activity

When clots occur with worsening pain or increasing exhaustion, it may indicate excessive blood loss.

Can Period Blood Clots Affect Fertility or Reproductive Health?

Period blood clots themselves do not cause infertility. However, the conditions that sometimes lead to heavy or unusual clotting can affect reproductive health.

• Fibroids: These noncancerous growths in the uterus can alter its shape or make it harder for an embryo to implant.
• Endometriosis: When tissue similar to the uterine lining grows outside the uterus, it can disrupt ovulation and create inflammation that affects fertility.
• Hormonal Imbalances: Irregular levels of oestrogen or progesterone can interfere with ovulation and the menstrual cycle.
• Early assessment is helpful: Identifying the cause of abnormal clotting can help manage symptoms and protect long-term reproductive health.
• Supports fertility planning: Understanding what’s happening makes it easier to plan for pregnancy and address any underlying issues.

What Medical Conditions Are Linked to Period Blood Clots?

Several gynaecological and hormonal conditions can contribute to heavier or abnormal menstrual clotting.

Some of the most common include:

• Uterine fibroids: Non-cancerous growths in the uterus that can lead to heavy bleeding and larger clots
• Endometriosis: When tissue similar to the uterine lining grows outside the uterus, it can cause pain and heavier periods
• Adenomyosis: When the uterine lining grows into the uterine muscle, often resulting in clotting and longer periods
• Polycystic ovary syndrome (PCOS): Hormonal imbalances that may trigger irregular, heavy or prolonged periods

Are Period Blood Clots a Sign of Hormonal Imbalance?

Yes, hormonal imbalances can play a role in heavy bleeding and the formation of period blood clots. Oestrogen and progesterone work together to control how the uterine lining builds up and sheds each month.

When this balance is disrupted, it can lead to:

• An excessively thick uterine lining: More tissue can result in more clots
• Uneven shedding: The lining may break down in chunks rather than gradually
• Heavier or longer periods: Bleeding may become prolonged or unusually heavy

Hormonal irregularities are commonly seen in conditions such as PCOS, thyroid disorders or during perimenopause.

How Are Abnormal Period Blood Clots Diagnosed?

When it comes to abnormal period blood clots, doctors focus on identifying the underlying cause rather than the clots themselves.

Medical evaluation may include:

• Detailed menstrual history: Your doctor will ask about the length, heaviness and pattern of your periods, as well as any pain or changes in clotting.
• Pelvic examination: A physical check of the uterus, ovaries and cervix can reveal fibroids, signs of endometriosis or other structural issues.
• Ultrasound imaging: This non-invasive scan provides a closer look at the uterus and ovaries to detect fibroids, adenomyosis or other abnormalities.
• Blood tests: These check hormone levels and screen for anaemia caused by heavy bleeding. They may also help identify thyroid problems or other hormonal imbalances.
• Hysteroscopy or biopsy (occasionally): In some cases, a small camera may be inserted into the uterus to inspect the lining or a tissue sample may be taken to rule out rare conditions or confirm a diagnosis.

What Treatment Options Are Available for Period Blood Clots?

Treatment for period blood clots depends on what’s causing them, how severe the symptoms are and whether you’re planning a pregnancy.

Options may include:

• Hormonal medications: Birth control pills, hormonal IUDs or other therapies may be used to regulate cycles, balance hormones and reduce heavy bleeding and clot formation.
• Non-hormonal treatments: Medications such as antifibrinolytics or anti-inflammatory drugs can help reduce menstrual blood loss without affecting hormones.
• Iron supplements: If heavy bleeding has led to anaemia, iron supplements may be recommended to restore energy levels and prevent complications.
• Targeted treatment for underlying conditions: Fibroids, endometriosis or adenomyosis may require specific treatments, ranging from medication to minimally invasive procedures.

When Should You Seek Medical Advice?

You should consider medical guidance if period blood clots interfere with your daily life or change suddenly.

Seek support if:

• Bleeding soaks through pads or tampons hourly
• Clots are consistently large
• Period pain worsens over time
• You feel fatigued or faint during menstruation

Conclusion

It is normal to have blood clots during your period, especially when your flow is heavy. For most women, period blood clots are not a cause for concern. However, if clots begin to increase in size or frequency and are accompanied by pain or fatigue, your body may be trying to signal that something has changed.

Knowing what’s normal for you makes it easier to decide when to check in with a doctor. In most cases, once the underlying cause is understood, symptoms can be managed and long-term health protected.