What is the evaluation and treatment for brown vaginal discharge in the second trimester of pregnancy?

Evaluation and Management of Brown Vaginal Discharge in Second Trimester Pregnancy

Brown vaginal discharge in the second trimester requires prompt ultrasound evaluation before any digital examination to rule out serious conditions such as placenta previa, vasa previa, or placental abruption. 1

Initial Assessment

Immediate Steps

1. Ultrasound evaluation first

   • Transabdominal ultrasound to assess:
     • Placental location and margin
     • Placental umbilical cord insertion
     • Cervix from external to internal os
     • Any vessels overlying the internal cervical os 2
   • Transvaginal ultrasound if needed for:
     • Better visualization of the cervix
     • Measurement of distance from placental margin to internal cervical os
     • Identification of any vessels overlying the cervical os 2

2. Physical examination (only after ultrasound confirms no placenta previa)

   • Visual inspection with speculum
   • Avoid digital examination until placental location is confirmed 1

Differential Diagnosis

Brown vaginal discharge in the second trimester may be caused by:

1. Physiologic causes

   • Post-coital spotting (often related to cervical friability)
   • Cervical irritation

2. Pathologic causes

   • Placenta previa or low-lying placenta
   • Placental abruption
   • Vasa previa
   • Cervical insufficiency
   • Preterm labor
   • Infection (bacterial vaginosis, candidiasis, trichomoniasis)

Infectious Causes Assessment

• Bacterial vaginosis (BV) is found in 9-23% of pregnant women 3
• BV is associated with preterm delivery, premature rupture of membranes, and other adverse pregnancy outcomes 4, 5
• Symptoms may include vaginal discharge, pruritus, or malodor, but women are often asymptomatic 3
• Diagnosis through:
  • Amsel's criteria (note: poor sensitivity for detecting BV) 6
  • Gram staining with Nugent scoring (gold standard) 6

Management Plan

If No Serious Pathology Identified

1. Outpatient management is appropriate if:

   • Spotting only (no heavy bleeding)
   • No abdominal pain or contractions
   • Normal fetal movement
   • No signs of infection or rupture of membranes
   • Ultrasound shows no placenta previa or abruption 1

2. For suspected infection:

   • If bacterial vaginosis is diagnosed:
     • Treatment options include:
       • Metronidazole 500 mg orally three times daily for 7-10 days 7
       • Note: Metronidazole should not be used in the first trimester of pregnancy 7

3. Patient instructions:

   • Pelvic rest (no intercourse) for 1-2 weeks
   • Monitor for increased bleeding, contractions, or decreased fetal movement
   • Return precautions for heavy bleeding, pain, contractions, or rupture of membranes 1
   • Schedule follow-up within 1 week for reassessment 1

If Serious Pathology Identified

1. Hospital admission for:

   • Significant bleeding
   • Placenta previa
   • Placental abruption
   • Signs of preterm labor 1

2. Management includes:

   • Continuous fetal monitoring
   • Preparation for possible emergency delivery
   • Administration of Rh immunoglobulin to Rh-negative women 1

Important Considerations

Risk Assessment

• Timing and amount of bleeding are important prognostic factors
• Spotting carries a better prognosis than heavy bleeding 1
• Partial bacterial vaginosis increases the likelihood of spontaneous preterm birth (OR 3.347, CI 1.642-6.823) 6

Pitfalls to Avoid

1. Never perform digital pelvic examination before ruling out placenta previa 1
2. Don't underestimate the significance of bleeding in the second trimester - it can lead to adverse perinatal and maternal outcomes 1
3. Don't rely solely on clinical appearance of vaginal discharge - studies show poor correlation between appearance and microscopic diagnosis 6
4. Don't forget to administer Rh immunoglobulin to Rh-negative women with bleeding in pregnancy 1

Follow-up

• Schedule follow-up within 1 week for reassessment
• Consider antenatal corticosteroids if risk factors for preterm delivery develop 1
• Continue monitoring for increased bleeding, contractions, or decreased fetal movement