Heavy Menstrual Bleeding is Also Known as Menorrhagia

Heavy menstrual bleeding (HMB) can have several causes, often related to underlying medical conditions, hormonal imbalances, or structural abnormalities within the reproductive system. Some of the common causes include:

Hormonal Imbalances

Imbalances in estrogen and progesterone can disrupt the normal regulation of the menstrual cycle, leading to a thickened endometrial lining and heavier bleeding.

Conditions like polycystic ovary syndrome (PCOS), thyroid disorders, and obesity can also contribute to hormonal imbalances.

Uterine Fibroids

These are benign (non-cancerous) growths within the uterine wall that can cause heavy bleeding, especially if they are large or located in certain areas of the uterus.

Uterine Polyps

Small, benign growths in the lining of the uterus can contribute to irregular or heavy bleeding.

Adenomyosis

This condition occurs when the endometrial tissue (lining of the uterus) grows into the muscle wall of the uterus, causing heavy, painful periods.

Bleeding Disorders

Conditions like von Willebrand disease or platelet disorders affect the blood’s ability to clot and can lead to heavy menstrual bleeding.

Endometrial Hyperplasia

Excessive growth of the endometrial lining, often due to unopposed estrogen, can lead to abnormally heavy periods.

Intrauterine Device (IUD)

Certain non-hormonal IUDs, like the copper IUD, can cause increased bleeding as a side effect.

Medications

Some medications, such as anticoagulants (blood thinners), anti-inflammatory drugs, and hormonal treatments, may contribute to heavy menstrual bleeding.

Cancer

Although less common, uterine, cervical, or endometrial cancers can cause abnormal or heavy bleeding, especially in postmenopausal individuals.

Pregnancy-Related Complications

Miscarriages or ectopic pregnancies can result in heavy bleeding and should be evaluated promptly.

Unknown Causes (Idiopathic)

In some cases, no clear cause is found. This is known as dysfunctional uterine bleeding.

A healthcare provider can help identify the underlying cause of HMB through exams, imaging tests, and blood work to determine the best treatment.

The pathophysiology of heavy menstrual bleeding (HMB) involves complex interactions between hormonal, vascular, and structural factors that lead to an abnormal increase in menstrual blood loss. Here is a breakdown of the main pathophysiological mechanisms:

Hormonal Dysregulation

• In a typical cycle, estrogen promotes the growth of the endometrial lining, while progesterone stabilizes it.
• Estrogen-Progesterone Imbalance: When there is an imbalance—such as in anovulatory cycles, where ovulation does not occur—progesterone is insufficient. This leads to unopposed estrogen stimulation, which causes excessive proliferation and thickening of the endometrial lining. A thicker lining results in more extensive tissue breakdown and bleeding during menstruation.
• Conditions such as Polycystic Ovary Syndrome (PCOS) and thyroid disorders can contribute to these hormonal imbalances, leading to HMB.

Endometrial Abnormalities

• Endometrial Hyperplasia: Excessive or prolonged estrogen exposure can cause the endometrium to thicken excessively. A thicker lining increases the surface area that sheds during menstruation, leading to heavier bleeding.
• Prostaglandin Dysregulation: Prostaglandins are compounds involved in regulating uterine contractions and blood vessel tone. In HMB, there may be an increase in vasodilatory prostaglandins, leading to excessive vasodilation and greater blood loss.

Structural Abnormalities of the Uterus

• Fibroids: These benign growths within the uterine wall can distort the uterine cavity, increase endometrial surface area, and disrupt normal contractility, contributing to heavier bleeding.
• Polyps: Endometrial or cervical polyps can increase bleeding by creating irregular areas of endometrial tissue that do not undergo normal shedding.
• Adenomyosis: This condition involves endometrial tissue growing into the muscle layer of the uterus. This abnormal tissue response can lead to an enlarged uterus and prolonged bleeding due to difficulty contracting and expelling blood effectively.

Vascular and Hemostatic Dysfunction

• Vascular Abnormalities: Abnormalities in the blood vessels within the endometrium can contribute to increased blood flow during menstruation. Dilated or fragile vessels may be more prone to bleeding.
• Coagulation Disorders: Some individuals may have underlying bleeding disorders, such as von Willebrand disease, that affect normal blood clotting. These disorders can prevent effective clotting within the endometrial vessels, leading to prolonged or excessive bleeding.

Uterine Contractility and Impaired Hemostasis

• During menstruation, the uterus normally contracts to help expel blood and tissue while compressing blood vessels to minimize bleeding. 
• Inadequate Platelet Aggregation and Fibrin Formation: Normally, platelets and fibrin form a clot to seal off blood vessels in the endometrial lining. Disruptions in platelet function or fibrin formation can impair hemostasis, resulting in prolonged bleeding.

These pathophysiological factors often overlap, making HMB a multifactorial condition. Diagnostic evaluation, including hormonal assays, imaging studies, and possibly biopsy, helps determine the predominant cause to guide treatment.

Here are the main steps in diagnosing HMB:

Patient History

• Menstrual History: The patient is asked about the duration, frequency, and quantity of menstrual bleeding, including the need to change sanitary products frequently (e.g. every 1-2 hours), bleeding lasting more than 7 days, passing large clots, or experiencing “flooding” episodes.
• Impact on Daily Life: The healthcare provider may ask about how bleeding affects daily activities, work, or social life, as well as symptoms of anemia (e.g. fatigue, dizziness).
• Medical and Surgical History: Previous diagnoses of hormonal disorders (e.g. PCOS, thyroid disease), bleeding disorders, and use of medications that may affect bleeding (e.g. blood thinners) are considered.
• Family History: A family history of bleeding disorders may indicate an inherited condition.

Physical Examination

• Pelvic Exam: A pelvic exam is performed to assess the uterus and other reproductive organs. This may help detect structural causes of HMB, such as fibroids, polyps, or signs of infection.
• General Physical Exam: Vital signs and a general exam may help identify signs of anemia (e.g. pale skin, rapid heart rate) or systemic conditions contributing to HMB.

Laboratory Tests

• Complete Blood Count (CBC): This is performed to assess hemoglobin levels and detect anemia, which can result from chronic blood loss.
• Iron Studies: Ferritin and other iron levels are tested to evaluate iron deficiency anemia.
• Hormonal Tests: Hormone levels, including thyroid hormones, follicle-stimulating hormone (FSH), and luteinizing hormone (LH), may be measured to identify hormonal imbalances.
• Coagulation Tests: In cases where a bleeding disorder is suspected, tests like prothrombin time (PT), activated partial thromboplastin time (aPTT), and von Willebrand factor assays may be performed to evaluate clotting function.

Imaging Studies

• Ultrasound: Transvaginal or pelvic ultrasound is commonly used to assess the uterus, ovaries, and surrounding structures. It helps identify structural abnormalities like fibroids, polyps, or adenomyosis.
• Sonohysterography: A saline-infused ultrasound (sonohysterography) may be used for more detailed imaging of the uterine cavity, particularly if polyps or submucosal fibroids are suspected.
• MRI: In some cases, an MRI may be ordered to provide detailed images of the uterus, especially for complex conditions like adenomyosis.

Endometrial Sampling and Biopsy

• An endometrial biopsy may be performed, especially in women over 35 or those with risk factors for endometrial cancer. The sample is examined for abnormal cells, endometrial hyperplasia, or malignancy.
• Hysteroscopy: In cases where imaging is inconclusive or further assessment is needed, a hysteroscopy (a procedure to view the uterine cavity with a camera) may be performed. This allows direct visualization of polyps, fibroids, or other abnormalities.

Menstrual Blood Loss Measurement (Optional)

• Pictorial Blood Loss Assessment Chart (PBAC): This is a tool that patients can use to track and quantify blood loss by noting the number of soaked pads/tampons and clots. A high PBAC score can indicate HMB.
• Alkaline Hematin Method: Rarely used in clinical practice due to complexity, this lab-based method measures menstrual blood loss to confirm HMB quantitatively.

Diagnosis often involves combining these findings to determine the most likely cause of HMB and guide appropriate treatment.

Heavy menstrual bleeding Prevention