What are the initial laboratory tests and treatment options for a 15-year-old female patient with heavy menstrual bleeding (menorrhagia)?

Laboratory Workup for a 15-Year-Old with Heavy Menses

For a 15-year-old with heavy menstrual bleeding, order a complete blood count (CBC), pregnancy test (β-hCG), thyroid stimulating hormone (TSH), and coagulation studies including PT, PTT, and von Willebrand disease (VWD) screening panel (VWF antigen, VWF ristocetin cofactor activity, and Factor VIII activity). 1, 2

Initial Essential Laboratory Tests

First-Tier Tests (Order Immediately)

• Complete Blood Count (CBC) to assess for anemia severity and rule out thrombocytopenia or thrombocytosis as potential causes of bleeding 1

  • Hemoglobin <7 g/dL represents severe anemia requiring urgent intervention including possible blood transfusion 3

• Pregnancy test (β-hCG) to exclude pregnancy complications including incomplete abortion or gestational trophoblastic disease 2

• Thyroid Stimulating Hormone (TSH) to evaluate thyroid function, as hypothyroidism can cause menorrhagia through hypocoagulable and hyperfibrinolytic states 4, 5

• Prothrombin Time (PT) and Activated Partial Thromboplastin Time (PTT) to screen for coagulation factor deficiencies 1

Critical Consideration for Adolescents

Up to 20% of adolescents with heavy menstrual bleeding have an underlying inherited bleeding disorder, making coagulation screening essential in this age group. 6

Von Willebrand Disease Screening Panel

If the bleeding history is strong (which it is in this case of heavy menses), order the VWD screening panel concurrently with initial tests 1:

• VWF antigen (VWF:Ag)
• VWF ristocetin cofactor activity (VWF:RCo)
• Factor VIII coagulant activity (FVIII)

All three tests are necessary for initial evaluation and can establish both diagnosis and VWD subtype 1. If VWF:RCo is abnormally low or the ratio of VWF:RCo to VWF:Ag is below 0.5-0.7, specialized VWD assays and multimer analysis should be considered 1.

Bleeding History Assessment

Use a validated bleeding assessment tool such as the ISTH BAT score to systematically evaluate bleeding risk 3. Normal reference ranges are <3 in children, and higher scores indicate need for hematologic investigation 3.

Key bleeding history questions to assess:

• Personal history of excessive bleeding with minor cuts, dental procedures, or surgeries 1
• Family history of bleeding disorders (98% of clinicians include this in initial assessment, and positive family history significantly increases likelihood of inherited bleeding disorder) 3
• Presence of easy bruising, epistaxis, or other mucocutaneous bleeding 1

Physical Examination Findings to Document

• Ecchymoses, hematomas, petechiae or other evidence of recent bleeding 1
• Signs of anemia including pallor, tachycardia 1
• Abdominal examination for masses or organomegaly 2
• Pelvic examination (speculum and bimanual) to exclude cervical lesions, polyps, or characterize uterine size and identify adnexal masses 2

Additional Tests Based on Clinical Context

• Prolactin levels if there are signs of hyperprolactinemia or galactorrhea 7
• Cervical cultures/NAAT for sexually transmitted infections if risk factors present or cervicitis suspected 2
• Pelvic ultrasound (transvaginal preferred) to evaluate for structural abnormalities including fibroids, polyps, adenomyosis, and endometrial thickness 2

Common Pitfalls to Avoid

Do not dismiss heavy bleeding as "normal" in adolescents simply because irregular cycles are common in the first 2-3 years after menarche 5. The immature hypothalamic-pituitary-ovarian axis can cause anovulation and irregular bleeding 7, but this should not preclude thorough evaluation for bleeding disorders and other pathology.

Never perform hysterectomy in adolescents, as it carries high major adverse event rates, elevated cardiovascular disease risk, mood disorders, and increased mortality 3.

Treatment Considerations After Diagnosis

Once laboratory results return:

• Combined oral contraceptives (30-35 μg ethinyl estradiol) are first-line medical management for menorrhagia 2
• Tranexamic acid reduces menstrual blood loss by 20-60% and can be used alone or with hormonal treatments 6, 8
• Levonorgestrel IUD is highly effective but may be less appropriate for adolescents 2
• DDAVP is used for heavy menstrual bleeding associated with certain inherited bleeding disorders like VWD 6
• Factor concentrate administration may be required during menses for severe inherited bleeding disorders 6