Uterine fibroids (leiomyomas or myomas) are non-cancerous growths that develop from the muscle tissue of the uterus. These growths are extremely common, affecting up to 80% of women by age 50, though many never experience symptoms. In certain circumstances, a fibroid can be spontaneously expelled. This rare event, often called “fibroid delivery” or “sloughing,” is an intense process where the body pushes the tissue out through the cervix and vagina.
The Mechanism of Fibroid Expulsion
The possibility of expulsion depends heavily on the fibroid’s location. Fibroids embedded entirely within the muscular wall (intramural) or those on the outer surface (subserosal) are highly unlikely to be expelled. The growths prone to natural expulsion are submucosal fibroids, which develop beneath the inner uterine lining, and pedunculated fibroids, which are attached by a stalk.
Expulsion is often triggered by a loss of blood supply to the growth, known as ischemic necrosis or degeneration. When a fibroid outgrows its blood source or the vascular connection is twisted, the tissue begins to die. The body recognizes this necrotic tissue as foreign material that must be removed from the uterine cavity.
This initiates a strong physiological response that mimics labor, causing the uterus to contract intensely. These powerful contractions dilate the cervix, forcing the detached or degenerating fibroid through the cervical canal and into the vagina. This event can occur spontaneously or following a procedure like Uterine Fibroid Embolization (UFE), which deliberately cuts off blood flow.
Identifying Passed Tissue
When tissue is passed, it is important to distinguish between a fibroid, a heavy blood clot, or something else. A passed fibroid is typically a fleshy mass with a firm, dense texture, unlike the soft consistency of a blood clot. Its color may be grayish or whitish rather than the dark red or purple of coagulated blood, reflecting the dead, muscular tissue.
Large blood clots associated with heavy menstrual bleeding are gel-like and can resemble pieces of fruit. These clots form when the menstrual flow is so heavy that the body’s natural anticoagulants cannot keep the blood liquid, causing coagulation in the uterus. A fibroid is a solid growth of smooth muscle cells, while a clot is a collection of blood cells and fibrin.
Another type of passed tissue is a decidual cast, a rare event where the entire lining of the uterus is shed in one piece, taking the shape of the uterine cavity. This tissue can look large and fleshy, but it is softer and more membranous than a dense fibroid. Since visual confirmation is not definitive, any unexpected passage of large tissue fragments warrants immediate medical attention to determine the tissue’s origin.
Immediate Steps and Medical Follow-Up
The first priority upon passing a large piece of tissue is to ensure personal safety and seek prompt medical care. If possible, the passed tissue should be collected and placed in a clean container for pathological examination. Laboratory analysis is the only definitive way to confirm the tissue is a benign fibroid and not another type of growth or pregnancy-related material.
It is helpful to note the time of expulsion, the estimated size of the tissue, and any accompanying symptoms, such as severe cramping or heavy bleeding. Excessive bleeding or a foul-smelling vaginal discharge requires immediate communication with a healthcare provider, as these signs may indicate an acute hemorrhage or a uterine infection. Infection is a risk if fibroid fragments remain partially attached or if the tissue remains in the uterine cavity.
A follow-up examination typically involves a pelvic ultrasound or hysteroscopy to assess the uterine cavity and confirm complete expulsion. The doctor must verify that no remnants of the fibroid remain, which could lead to continued bleeding or infection. This assessment confirms the uterus is healthy and allows discussion of treatment options for other remaining fibroids.