What is the most likely diagnosis for a pregnant woman at 37 weeks gestation presenting with severe abdominal pain, hypotension, tachycardia, and no vaginal bleeding?

Placental Abruption (Abruptio Placentae)

The most likely diagnosis is placental abruption (Option B), given the classic triad of severe abdominal pain, hemodynamic instability (hypotension and tachycardia), and absence of vaginal bleeding in a term pregnancy. 1

Clinical Reasoning

Key Diagnostic Features Present

• Severe abdominal pain with hemodynamic compromise: The patient presents with hypotension (90/56 mmHg) and tachycardia (130/min), indicating significant blood loss despite no visible vaginal bleeding 2

• Concealed hemorrhage: Approximately 20-30% of placental abruptions present without vaginal bleeding when blood is trapped between the placenta and uterine wall 1, 3

• Cold and diaphoretic appearance: These signs indicate hypovolemic shock from significant retroplacental hemorrhage 2

• Closed cervical os: This finding is consistent with placental abruption, where bleeding occurs behind the placenta rather than through the cervix 1

Why Other Diagnoses Are Less Likely

Placenta Previa (Option C) is effectively ruled out because:

• Placenta previa characteristically presents with painless vaginal bleeding and a soft, non-tender uterus 1
• This patient has severe pain, which is the hallmark distinguishing feature of abruption 1
• Placenta previa affects approximately 1 in 200 pregnancies but does not cause the hemodynamic instability seen here without visible bleeding 1

Amniotic Fluid Embolism (Option A) is less likely because:

• AFE typically presents with acute respiratory distress, cardiovascular collapse, and altered mental status as primary features 4
• The predominant symptom here is abdominal pain with shock, not the classic triad of hypoxia, hypotension, and coagulopathy seen in AFE 4

Septic Shock (Option D) is unlikely because:

• No fever or signs of infection are mentioned 4
• The acute presentation with severe abdominal pain points to an obstetric hemorrhagic emergency rather than sepsis 2

Uterine Rupture (not listed but worth excluding):

• Exceedingly rare in a primigravida with no history of prior cesarean delivery or uterine surgery 1, 5
• Would typically present with even more severe hemodynamic instability and often with palpable fetal parts 5

Clinical Manifestations of Placental Abruption

The classic presentation includes 2, 6:

• Vaginal bleeding (70% of cases) - notably absent in 30% with concealed hemorrhage
• Abdominal pain (51% of cases) - present in this patient
• Fetal heart rate abnormalities (69% of cases) - should be assessed immediately
• Neither bleeding nor pain present in 19% of cases - emphasizing diagnostic challenges 6

Critical Management Considerations

Immediate actions required 2:

• Emergency cesarean delivery given term gestation, hemodynamic instability, and likely fetal compromise
• Aggressive volume resuscitation with crystalloids and blood products
• Coagulation studies to assess for disseminated intravascular coagulopathy (DIC), which complicates severe abruption 2
• Continuous fetal monitoring if not already performed

Common pitfall: The absence of vaginal bleeding does not exclude placental abruption - concealed hemorrhage can result in massive blood loss with minimal external signs 3, 2