Why am I passing large blood clots during my period?

Passing large clots during your period usually means the bleeding is heavy enough that blood is pooling in the uterus and clotting before it exits. Some clotting can be normal, but frequent or large clots—especially when paired with flooding, severe cramps, pelvic pressure, or fatigue—can be a sign that something is driving abnormally heavy uterine bleeding rather than “just a bad period.”

Two common underlying causes we evaluate for are adenomyosis (endometrial-like tissue within the uterine muscle, often linked with heavy bleeding and painful periods) and fibroids, and it’s also possible for adenomyosis to overlap with endometriosis and intensify symptoms. Because the right treatment depends on the cause, our team focuses on your full symptom pattern and uses expertly interpreted ultrasound and, when helpful, MRI to look for adenomyosis and other pelvic conditions that can be missed or mislabeled.

If you’re passing clots larger than a quarter, soaking through protection quickly, feeling lightheaded, or your bleeding is disrupting daily life, it’s worth a deeper workup—not dismissal. You can reach out to schedule a consultation so we can map out what’s most likely in your case and what options (medical, procedural, or surgical) make sense for your goals, including fertility and long-term relief.