Menstrual Abnormalities - Abnormal Uterine Bleeding

Written by Wesam Tamimi, M.D.

Keywords: Abnormal uterine bleeding, PALM-COEIN, heavy menstrual bleeding, endometrial hyperplasia, anovulation, PCOS, menorrhagia, hysterectomy, endometrial biopsy.

Overview

Abnormal uterine bleeding (AUB) encompasses a range of menstrual irregularities, including excessive, prolonged, or irregular bleeding, which may result from underlying conditions such as hormonal imbalances, structural uterine abnormalities, or systemic diseases. It is classified using the PALM-COEIN system, differentiating between structural causes (e.g., polyps, fibroids, malignancies) and non-structural factors (e.g., coagulopathy, ovulatory dysfunction, iatrogenic causes). Clinical features of AUB vary depending on the bleeding pattern and may include symptoms like pelvic pain, anemia, and dysmenorrhea. Diagnosis involves a comprehensive evaluation, including history, physical examination, cytologic testing, ultrasound, and sometimes biopsy. Management is tailored to the patient’s age, underlying cause, and severity of symptoms, with treatments ranging from hormonal therapy and surgical interventions to hysterectomy in severe cases.

Definition

Abnormal uterine bleeding (AUB) refers to any deviation from normal menstrual patterns, including excessive, irregular, or unexpected bleeding. It may result from pregnancy-related complications, systemic diseases, or malignancies.

Classification

Table 1: Patterns of abnormal uterine bleeding (AUB)

Etiology

AUB is categorized using the PALM-COEIN classification:

Table 2: Structural causes of abnormal uterine bleeding (PALM)

Table 3:  Non-structural causes of abnormal uterine bleeding (COEIN)

Pathophysiology

AUB results from hormonal imbalances, endometrial abnormalities, or structural defects.

●       Anovulatory bleeding: Lack of progesterone → unopposed estrogen → endometrial overgrowth and irregular shedding.

●       Ovulatory bleeding: Defective hemostasis or vascular fragility in the endometrium.

●       Structural lesions: Fibroids, polyps, and malignancies alter uterine architecture, affecting bleeding patterns.

Clinical Features

Types of bleeding

●       Heavy bleeding (menorrhagia): >80 mL or >7 days.

●       Irregular bleeding: Unpredictable cycles.

●       Frequent bleeding (polymenorrhea): <21 days.

●       Infrequent bleeding (oligomenorrhea): >35 days.

●       Postmenopausal bleeding: Occurs >12 months after menopause.

Associated symptoms

●       Pelvic pain: Suggests fibroids, adenomyosis, or endometrial pathology.

●       Dysmenorrhea (painful periods): Seen in endometriosis or fibroids.

●       Clots: Common in heavy bleeding.

●       Fatigue/pallor: Due to anemia.

●       Fever/discharge: Suggests infection (endometritis).

●       Hirsutism/acne: Suggests PCOS or androgen-secreting tumors.

Physical exam findings

●       Pallor: Sign of anemia.

●       Pelvic mass: Could indicate fibroids, adenomyosis, or tumors.

●       Tender uterus: Suggests endometritis or adenomyosis.

●       Cervical lesions: Check for polyps or malignancy.

Diagnosis

Initial evaluation

●       History, physical examination, cytologic examination, pelvic ultrasound, blood tests are first-line investigations.

●       Blood tests exclude systemic diseases, pregnancy, or trophoblastic disease.

o   Tests include: Complete Blood Count (CBC), β-hCG, Thyroid-Stimulating Hormone (TSH).

Detailed evaluation

History

●       Identify menstrual flow amount, cycle length, duration of bleeding, intermenstrual/contact bleeding.

●       Consider last menstrual period (LMP), age at menarche & menopause, general health changes.

●       Encourage recording bleeding patterns to distinguish abnormal from normal variations.

Physical examination

●       Enlarged, irregular uterus → Suggests leiomyomas.

●       Symmetrically enlarged uterus → Suggests adenomyosis or endometrial carcinoma.

●       Cervical polyps, cancerous lesions, or inflammatory vaginal conditions can be visualized.

●       Decidual reaction in pregnancy can cause bleeding (appears as a friable, erythematous lesion).

Cytologic examination (pap Smear)

●       Screens for cervical intraepithelial neoplasia & cervical carcinoma.

●       Abnormal smears require further evaluation.

Pelvic ultrasound

●       Essential in gynecologic evaluation, performed transvaginally (detailed) or transabdominally (broader view).

●       Evaluates endometrial thickness, fibroids, intrauterine polyps, adenomyosis.

●       Persistent thick/irregular endometrium → Suspicious for endometrial pathology (requires biopsy).

Sonohysterography: Saline infusion ultrasound enhances detection of polyps, fibroids, and endometrial abnormalities.

Endometrial biopsy: If bleeding persists or biopsy is inconclusive → Consider hysteroscopy or dilatation & curettage (D&C).

●       Methods: Novak curette, Duncan curette, Kevorkian curette, Pipelle biopsy.

Hysteroscopy: Gold standard for evaluating intrauterine pathology, allows for immediate biopsy/removal of lesions.

Dilatation & curettage (D&C)

●       Previously the gold standard, now often replaced by hysteroscopy.

●       Done under local or general anesthesia.

●       Limitations: Blind procedure, limited accuracy for focal lesions (polyps, fibroids).

Management

Table 4: Treatment approach based on age group

Illustration 1. Treatment approach for abnormal uterine bleeding

Reference

Shushan, A. (2024). Complications of menstruation & abnormal uterine bleeding. In A. H. DeCherney, A. S. Roman, L. Nathan, & N. Laufer (Eds.), Current Diagnosis and Treatment Obstetrics and Gynecology (12th ed., pp. 621–630). McGraw-Hill Education.