Postmenopausal bleeding (PMB) is defined as any vaginal bleeding or spotting that occurs 12 months or more after a woman’s final menstrual period. After a full year without menstruation, the uterus is generally quiescent, and any blood loss is considered abnormal. Even a single episode of light discharge or spotting falls under the classification of PMB and warrants prompt medical attention. While PMB is relatively common, it must always be investigated by a healthcare professional.
Why Postmenopausal Bleeding Requires Immediate Investigation
PMB should never be dismissed as an event that will resolve on its own, regardless of the amount or frequency of the blood loss. Delaying evaluation sacrifices the opportunity for the earliest possible detection of a serious underlying condition. Even if the bleeding is light and stops quickly, it requires a medical diagnosis to determine its origin.
The primary concern surrounding PMB is its link to endometrial cancer, which is cancer of the uterine lining. Approximately 90% of women ultimately diagnosed with endometrial cancer first presented due to postmenopausal bleeding. This makes PMB the most common presenting symptom of this malignancy.
Although most PMB cases are caused by benign conditions, the risk of malignancy necessitates a full workup for every patient. About 9% to 10% of women who experience PMB are ultimately diagnosed with endometrial cancer. Early diagnosis of this cancer, before it has spread, is associated with a significantly better prognosis.
This diagnostic urgency requires the healthcare provider to initiate an evaluation process without delay. Waiting to see if the bleeding recurs postpones the potential identification and treatment of precancerous changes or early-stage cancer. Therefore, any instance of PMB triggers a medical investigation to rule out the most serious causes.
The Underlying Causes of Bleeding
The underlying reasons for PMB are diverse, ranging from common benign changes to less frequent, serious malignancies. The most frequent cause is atrophy of the genital tract, involving the vagina or the endometrium. The loss of estrogen after menopause causes the tissues of the vaginal walls and uterine lining to become thin and fragile, a condition called genitourinary syndrome of menopause (GSM).
This tissue thinning can lead to spontaneous bleeding or bleeding easily triggered by minor trauma, such as sexual intercourse. Endometrial polyps, which are usually benign tissue growths inside the uterus or cervix, are another common benign cause of PMB. Although most polyps are non-cancerous, they are typically removed and sent for laboratory analysis because a small fraction may harbor cancerous cells.
More serious causes requiring urgent attention include endometrial hyperplasia and endometrial cancer. Endometrial hyperplasia is an abnormal thickening of the uterine lining, often resulting from excessive estrogen stimulation without the counterbalancing effect of progesterone. This condition is classified by the presence of cellular abnormalities, known as atypia.
Hyperplasia without atypia is considered benign, but atypical hyperplasia is recognized as a precancerous state with a higher risk of progressing to endometrial cancer. Endometrial cancer is the most serious potential diagnosis, often linked to risk factors that cause unopposed estrogen exposure, such as obesity. Less common causes of PMB include unscheduled bleeding related to hormone replacement therapy, or non-gynecologic bleeding mistaken for vaginal bleeding.
How Doctors Determine the Diagnosis
The diagnostic process begins with a thorough medical history and a physical examination, including a pelvic exam, to identify obvious sources of bleeding. The primary diagnostic tool used next is the transvaginal ultrasound (TVUS), which measures the thickness of the endometrial lining using sound waves.
Measuring endometrial thickness is a highly sensitive screening step because a thin lining virtually rules out endometrial cancer. An endometrial thickness of four millimeters or less has a negative predictive value of over 99% for excluding cancer, often making further invasive testing unnecessary. If the lining measures greater than four millimeters, or if the ultrasound is inconclusive, the diagnostic pathway moves to tissue sampling.
The standard procedure for obtaining tissue is an office endometrial biopsy, often performed using a small suction device like a Pipelle. This device collects a sample of the uterine lining, which is sent to a pathology lab for microscopic examination to check for hyperplasia or cancer. Although this is a quick outpatient procedure, it can sometimes miss focal lesions, such as a polyp.
If the office biopsy is non-diagnostic, if bleeding persists despite a negative result, or if a focal lesion is suspected, a more comprehensive procedure is performed. This involves a hysteroscopy, where a thin, lighted camera is inserted through the cervix to visually inspect the entire uterine cavity. During the hysteroscopy, a dilation and curettage (D&C) procedure can be performed to sample the entire uterine lining, providing the most definitive diagnosis.
Treatment Options Based on the Underlying Condition
Treatment for PMB is highly individualized and depends on the specific cause identified during the diagnostic workup. For genitourinary atrophy, treatment focuses on restoring tissue health. This is typically managed with low-dose, localized estrogen therapy, such as vaginal creams, rings, or tablets, which help thicken the fragile tissues and resolve the bleeding.
If the bleeding originates from a polyp, the standard treatment is surgical removal, known as a polypectomy. This procedure is often performed during a hysteroscopy, allowing the physician to visually guide the removal of the growth. The polyp is always sent for pathology to confirm its benign nature or identify any malignancy.
When the diagnosis is endometrial hyperplasia, management depends on the presence or absence of cellular atypia. Non-atypical hyperplasia is often treated with progestin hormone therapy, which helps shed the thickened lining and reverse the changes. Atypical hyperplasia, due to its higher risk of cancer progression, may be treated more aggressively, sometimes requiring a hysterectomy.
For a confirmed diagnosis of endometrial cancer, treatment is determined by the cancer type, grade, and stage. The initial treatment is usually surgery, specifically a hysterectomy, often accompanied by the removal of the fallopian tubes and ovaries. Depending on the extent of the disease, this may be followed by additional therapies, such as radiation or chemotherapy.