What is the initial workup for a 13-week pregnant patient presenting to the emergency department with vaginal bleeding without pain?

Emergency Department Workup for Vaginal Bleeding at 13 Weeks Pregnancy

Transabdominal ultrasound followed by transvaginal ultrasound is the cornerstone of evaluation for a 13-week pregnant patient presenting with painless vaginal bleeding to the emergency department. 1, 2

Initial Assessment

• Vital signs: Assess hemodynamic stability (blood pressure, heart rate)
• Bleeding assessment: Quantify amount, duration, and presence of clots
• Abdominal examination: Evaluate for tenderness, rebound, or guarding
• Avoid digital vaginal examination until placenta previa is excluded by ultrasound 2

Laboratory Studies

• Complete blood count (CBC) to assess hemoglobin/hematocrit
• Blood type and Rh status
• Quantitative β-hCG (though not necessary if ultrasound confirms viable intrauterine pregnancy)
• Coagulation profile if heavy bleeding is present

Imaging Protocol

1. Transabdominal ultrasound: First-line imaging modality 1, 2

   • Visualize the gestational sac, fetal cardiac activity
   • Assess placental location and inferior placental margin
   • Evaluate placental umbilical cord insertion
   • Examine the cervix

2. Transvaginal ultrasound: Indicated when 1, 2

   • Transabdominal images are inadequate or inconclusive
   • Detailed assessment of cervix or placental location is needed
   • Suspected ectopic pregnancy requires evaluation

3. Doppler ultrasound: Essential for 1, 2

   • Identifying vasa previa
   • Distinguishing between fetal and maternal vessels

Key Diagnoses to Consider

• Viable intrauterine pregnancy with subchorionic hemorrhage

  • Management: Observation and follow-up ultrasound

• Placenta previa

  • Management: Pelvic rest, avoid digital examination, possible hospitalization if bleeding is significant 2

• Ectopic pregnancy

  • Note: Can present with painless bleeding
  • Transvaginal ultrasound can detect ectopic pregnancy even with β-hCG <1,000 mIU/mL 2

• Threatened abortion

  • Management: Observation with follow-up

Discharge Criteria

Patients can be discharged if they meet all criteria: 2

• Hemodynamically stable
• Minimal bleeding
• Confirmed viable intrauterine pregnancy
• No evidence of placenta previa or other concerning pathology
• Reliable follow-up arranged

Admission Criteria

Consider admission for: 2

• Hemodynamic instability
• Heavy bleeding
• Confirmed placenta previa with bleeding
• Uncertain diagnosis requiring further evaluation

Important Pitfalls to Avoid

1. Never perform digital vaginal examination before excluding placenta previa by ultrasound 2

2. Don't rely solely on β-hCG levels without imaging - transvaginal ultrasound can detect both intrauterine and ectopic pregnancies even with low β-hCG levels 2

3. Don't dismiss patient concerns - studies show patients primarily expect ultrasound and blood work to evaluate fetal well-being 3

4. Don't forget Rh status - administer RhoGAM to Rh-negative women with bleeding

5. Don't miss high-risk populations - ED visits for vaginal bleeding in early pregnancy are higher among black, Hispanic, and uninsured women 4

By following this structured approach, emergency physicians can effectively evaluate and manage patients presenting with vaginal bleeding at 13 weeks gestation, ensuring optimal outcomes for both mother and fetus.