What is the initial workup and management for abnormal uterine bleeding (AUB) in a 16-year-old female?

Workup for Abnormal Uterine Bleeding in a 16-Year-Old Female

The initial workup for abnormal uterine bleeding (AUB) in a 16-year-old female should include pregnancy testing, thyroid-stimulating hormone and prolactin level measurements, and transvaginal ultrasound (or transabdominal ultrasound if the patient is a virgin), as anovulation is the most common cause of AUB in adolescents. 1, 2

Initial Assessment

• Obtain a detailed menstrual history including regularity, duration, frequency, and volume of bleeding 1
• Assess for signs of anemia (fatigue, pallor, tachycardia) 3
• Evaluate for signs of hyperandrogenism (acne, hirsutism) that may suggest polycystic ovary syndrome 1
• Screen for bleeding disorders, especially if heavy bleeding began at menarche (von Willebrand disease is present in 13% of adolescents with AUB) 4
• Check vital signs to assess for hemodynamic instability in cases of acute heavy bleeding 5

Laboratory Testing

• Pregnancy test (β-hCG) to rule out pregnancy-related bleeding 1, 2
• Complete blood count to assess for anemia 3
• Thyroid-stimulating hormone (TSH) to rule out thyroid dysfunction 1, 2
• Prolactin level to rule out hyperprolactinemia 1, 2
• Consider coagulation studies (PT, PTT, von Willebrand factor) if heavy bleeding began at menarche or if there is a family history of bleeding disorders 4

Imaging

• Transabdominal ultrasound is the preferred initial imaging modality for virgins 1
• Transvaginal ultrasound may be appropriate in sexually active adolescents 1
• Ultrasound helps identify structural causes (polyps, adenomyosis, leiomyoma) 1, 2
• Saline infusion sonohysterography or hysteroscopy may be considered if initial ultrasound is inconclusive or if structural abnormalities are suspected 1, 2

Management Approach

• For mild to moderate bleeding with anovulation (most common in adolescents):

  • Combined hormonal contraceptives are first-line treatment 1, 3
  • Progestin-only options (oral, injectable, or intrauterine) are alternatives 1
  • NSAIDs can reduce bleeding volume by 20-40% 3, 4

• For acute heavy bleeding with hemodynamic stability:

  • High-dose combined hormonal contraceptives with tapering schedule 3
  • Tranexamic acid (antifibrinolytic) can reduce bleeding volume 3, 4

• For severe bleeding with hemodynamic instability:

  • Hospitalization for IV fluid resuscitation and parenteral hormonal therapy 4
  • Blood transfusion if hemoglobin is severely decreased 4

• For bleeding with structural abnormalities:

  • Treatment directed at the specific pathology identified 1, 5
  • Surgical options are rarely needed in adolescents but may include hysteroscopic removal of polyps if present 1

Special Considerations

• Anovulation is extremely common in the first 2-3 years after menarche due to immaturity of the hypothalamic-pituitary-ovarian axis 3
• Endometrial biopsy is rarely indicated in adolescents unless there are specific risk factors for endometrial cancer 5
• If medical treatment fails, further investigation with advanced imaging or hysteroscopy is indicated 1
• Consider extragenital causes including thyroid disorders, diabetes, obesity, and psychological stress 6

Follow-up

• Monitor response to treatment with menstrual calendar 5
• Follow hemoglobin levels if anemia was present 4
• Adjust treatment based on response and tolerability 1, 5