How should a 38‑week pregnant patient presenting with vaginal bleeding be managed?

Management of Vaginal Bleeding at 38 Weeks Gestation

Perform immediate ultrasound evaluation before any digital vaginal examination to exclude placenta previa, vasa previa, and placental abruption, as digital examination can precipitate catastrophic hemorrhage if these conditions are present. 1, 2, 3

Immediate Assessment and Safety Protocol

Critical First Step: Imaging Before Examination

• Digital vaginal examination is absolutely contraindicated until ultrasound has definitively excluded placenta previa, low-lying placenta, and vasa previa, as examination before imaging can cause life-threatening hemorrhage in these conditions. 1, 3

• Assess hemodynamic stability immediately by checking blood pressure and heart rate, as normal vital signs do not exclude serious pathology such as placental abruption, which can present with normal hemodynamics initially but rapidly deteriorate. 2, 3

• Establish large-bore intravenous access and prepare for potential fluid resuscitation and blood product transfusion if bleeding is significant. 4

Distinguish Normal from Pathologic Bleeding

• Normal "bloody show" at 38 weeks is characterized as pink or brown-tinged mucus, minimal in volume, and does not soak through pads or require changing protection. 1, 2

• Pathologic bleeding is bright red, flows continuously, soaks through pads, or is accompanied by clots—this requires immediate ultrasound evaluation. 2

Ultrasound Evaluation Components

Comprehensive Imaging Assessment

• Transabdominal ultrasound should be performed first, followed by transvaginal ultrasound if needed, to assess placental location and its relationship to the internal cervical os, as placenta previa affects approximately 1 in 200 pregnancies at delivery. 1, 5

• Evaluate for placental abruption, recognizing that ultrasound identifies at most 50% of cases, so clinical suspicion must remain high even with negative initial imaging. 1, 3

• Perform Doppler velocimetry to detect vasa previa, as vessels overlying the internal cervical os can be subtle but carry risk of fetal exsanguination with rupture of membranes. 1, 3

• Assess cervical length and any cervical change, as cervical change with term labor can cause bleeding. 1

• In patients with prior cesarean delivery, evaluate for uterine rupture by looking for disruption of the myometrium or lower uterine segment thickness <2.5 mm. 1

Fetal and Maternal Monitoring

• Initiate continuous electronic fetal heart rate monitoring to assess for decelerations, loss of variability, or bradycardia, which may indicate compromised placental perfusion. 2

• Obtain complete blood count to check hemoglobin, as a hemoglobin drop suggests moderate blood loss requiring potential iron supplementation or transfusion. 2

• Check coagulation studies (platelet count, prothrombin time, partial thromboplastin time, fibrinogen levels) if bleeding is excessive, defined as estimated blood loss ≥1,500 mL. 6

Management Based on Diagnosis

If Placenta Previa is Identified

• Mandate pelvic rest and hospitalization if significant bleeding occurs, with preparation for cesarean delivery. 5

• Avoid digital examination entirely, as transvaginal ultrasound is safe even with placenta previa and provides superior visualization. 1

If Placental Abruption is Suspected

• Placental abruption is the most common cause of serious vaginal bleeding, occurring in 1% of pregnancies, and may require rapid operative delivery to prevent neonatal morbidity and mortality. 5

• Prepare for potential massive transfusion protocol with packed red blood cells, fresh frozen plasma, and platelets in a fixed ratio if hemorrhage is uncontrolled. 6

If Vasa Previa is Confirmed

• Proceed immediately to cesarean delivery before rupture of membranes to prevent fetal exsanguination. 1, 5

If No Placental Abnormality is Found

• Perform speculum examination (not digital) to assess for cervical lesions, polyps, cervicitis, or cervical change consistent with labor. 1, 3

• If bleeding is minimal and consistent with bloody show, continue expectant management with close monitoring for progression of labor. 2

Common Pitfalls to Avoid

• Never assume that normal vital signs exclude serious pathology, as placental abruption can present with normal hemodynamics initially but rapidly deteriorate. 2

• Do not rely solely on ultrasound to exclude placental abruption, as imaging misses up to 50% of cases—maintain high clinical suspicion based on symptoms. 1, 3

• Avoid performing digital cervical examination before ultrasound if bleeding increases beyond minimal bloody show, as this can precipitate catastrophic hemorrhage if placenta previa or vasa previa is present. 1, 2

Preparation for Potential Complications

• Keep the patient warm (body temperature >36°C) and avoid acidosis, as many clotting factors function poorly in hypothermia. 6

• Re-dose prophylactic antibiotics if blood loss exceeds 1,500 mL. 6

• Have interventional radiology available for hypogastric artery embolization if uncontrolled hemorrhage ensues and surgical measures are inadequate. 6

• Consider pelvic pressure packing for patient stabilization if experiencing acute uncontrolled hemorrhage refractory to other measures. 6