What is the most likely cause of ongoing vaginal bleeding in a 38-week gestation gravida 2 para 1 (second pregnancy, one previous birth) patient with a history of previous uncomplicated cesarean delivery (cesarean section) and no prenatal care, who delivered a large infant precipitously and continues to bleed despite uterotonic medications and uterine massage?

Most Likely Cause: Genital Tract Laceration

In this patient with ongoing postpartum hemorrhage despite a firm uterine fundus and administration of uterotonic medications, genital tract laceration is the most likely cause of bleeding. 1

Clinical Reasoning

Why Uterine Atony is Ruled Out

• The firm uterine fundus effectively excludes uterine atony as the cause. Uterine atony, which accounts for 70-80% of all postpartum hemorrhage cases, presents with a soft, boggy uterus that fails to contract properly. 1
• The patient received vigorous uterine massage and uterotonic medications with documented firm fundus, making atony an unlikely diagnosis. 2

Why Genital Tract Laceration is Most Likely

• When postpartum hemorrhage occurs with a firm, well-contracted uterus, genital tract trauma becomes the leading cause. 1
• This patient has multiple risk factors for genital tract lacerations:
  • Precipitous delivery (rapid, uncontrolled delivery increases laceration risk) 1
  • Large infant (macrosomia at 4.1 kg) increases tissue trauma during delivery 1
  • History of prior cesarean section may alter tissue integrity of the lower genital tract 2
  • No prenatal care (potential undiagnosed conditions, no preparation for delivery) 2

Why Other Causes are Less Likely

Retained placental fragments: While placental fragments were manually extracted, this was documented as "small fragments removed in pieces," suggesting the majority of placenta was delivered. Retained products of conception (RPOC) complicate approximately 1% of third-trimester deliveries and typically cause delayed postpartum hemorrhage rather than immediate bleeding. 2

Uterine rupture: Although the patient has a history of cesarean section (increasing rupture risk), uterine rupture typically presents with:

• Severe abdominal pain 2
• Loss of fetal station during labor 2
• Hemodynamic instability disproportionate to visible bleeding 2
• The firm, intact uterine fundus on examination argues strongly against rupture 2

Coagulopathy: While possible (especially with amniotic fluid embolism or dilutional coagulopathy), there are no clinical indicators mentioned such as bleeding from IV sites, petechiae, or other systemic bleeding manifestations. 2

Diagnostic Approach

The American College of Radiology recommends the following algorithm for postpartum hemorrhage evaluation: 1

1. Assess uterine tone first - Already done; fundus is firm 1
2. Thoroughly inspect the genital tract for lacerations - This is the critical next step 1
3. Verify complete placental delivery - Partially addressed with manual extraction 1
4. Assess for coagulopathy if bleeding persists - Consider if no laceration found 1

Specific Examination Technique

• Systematic visual inspection under adequate lighting of:
  • Cervix (circumferentially) 2
  • Vaginal walls (anterior, posterior, lateral) 2
  • Perineum and periurethral area 2
• Look for arterial bleeding sources (pulsatile, bright red blood) 2
• Consider examination under anesthesia if patient cannot tolerate adequate inspection 2

Critical Pitfalls to Avoid

• Never assume bleeding is from retained tissue without ruling out lacerations first when the uterus is firm. 1
• Do not perform blind uterine curettage for presumed retained products without adequate visualization of the genital tract. This could worsen bleeding from an unrecognized laceration or cause uterine perforation. 3
• Avoid excessive focus on the uterus when it is clearly well-contracted. The bleeding source must be elsewhere. 1

Management Implications

Once lacerations are identified:

• Immediate surgical repair with absorbable suture under adequate anesthesia and lighting 2
• Ensure hemostasis with figure-of-eight sutures for arterial bleeders 2
• Consider packing if diffuse oozing from multiple small lacerations 2

If no laceration is found despite thorough examination:

• Reconsider retained placental tissue with transvaginal ultrasound with Doppler (sensitivity 90-95% for RPOC) 3
• Assess for coagulopathy with PT/PTT, fibrinogen, platelet count 2
• Consider CT angiography if hemodynamically stable to identify occult bleeding source 2