What is the diagnosis for a pregnant woman at 37 weeks gestation presenting with a 1-week history of cough and expectoration, severe hypoxia, and normal blood pressure, who develops hypertension and worsening hypoxia post-termination of pregnancy, with an ejection fraction (EF) of 40%?

Peripartum Cardiomyopathy (PPCM)

This patient most likely has peripartum cardiomyopathy (PPCM), a diagnosis of exclusion presenting with heart failure and reduced ejection fraction (40%) in the late pregnancy/early postpartum period, complicated by severe respiratory infection requiring mechanical ventilation.

Diagnostic Criteria and Clinical Presentation

PPCM is defined as idiopathic cardiomyopathy presenting with heart failure secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery, with EF nearly always reduced below 45%. 1 This patient's EF of 40% at 37 weeks gestation, worsening after delivery, fits this definition precisely.

Key Diagnostic Features Present in This Case:

• Timing: Presentation at 37 weeks with worsening post-delivery is classic for PPCM, which occurs "towards the end of pregnancy or in the months following delivery" 1
• Cardiac dysfunction: EF of 40% meets the diagnostic threshold of <45% 1
• Respiratory failure: Severe hypoxia requiring intubation is consistent with acute heart failure presentation, which occurs frequently in PPCM 1
• Post-delivery hypertension: Development of hypertension after pregnancy termination may represent fluid shifts and increased afterload unmasking cardiac dysfunction 1

Why PPCM Rather Than Other Diagnoses

Respiratory Infection as Precipitant, Not Primary Cause:

The initial presentation with cough and expectoration likely represents either:

• Viral pneumonia triggering cardiac decompensation in underlying subclinical PPCM 2
• Pulmonary edema from heart failure misinterpreted as pneumonia (a common diagnostic pitfall) 1

The fact that she developed worsening hypoxia and hypertension POST-delivery despite antibiotics and diuretics strongly suggests the primary problem is cardiac, not infectious. Pure pneumonia would improve with antibiotics, not worsen after delivery. 1

Excluding Other Differential Diagnoses:

• Amniotic fluid embolism: Would present with sudden cardiovascular collapse, hypotension (not hypertension), and coagulopathy during or immediately after delivery—not a week-long prodrome 1, 3
• Pulmonary embolism: Typically presents with acute onset, not gradual worsening over a week, and would not explain the reduced EF of 40% 4
• Myocardial infarction: Would show specific ECG changes and troponin elevation; less likely in this age group without traditional risk factors 1
• Pre-eclampsia/eclampsia: Hypertension developed POST-delivery, not before, making this less likely as primary diagnosis 1

Pathophysiology Explaining This Clinical Course

PPCM results from unbalanced oxidative stress during late pregnancy leading to cleavage of prolactin into a 16 kDa fragment that is angiostatic, pro-apoptotic, and pro-inflammatory, causing vascular damage and heart failure. 5

The respiratory infection likely increased oxidative stress, precipitating cardiac decompensation in a woman with subclinical PPCM. 5 The worsening after delivery reflects:

• Removal of pregnancy's compensatory mechanisms (increased preload, cardiac output) 1, 6
• Fluid shifts postpartum increasing cardiac workload 1
• Continued prolactin production driving ongoing cardiac injury 5

Management Approach

Acute Phase (Current):

• Continue standard heart failure management: Diuretics (furosemide), afterload reduction, and supportive care as already initiated 1
• Broad-spectrum antibiotics are appropriate given respiratory symptoms, though improvement suggests cardiac etiology predominates 1
• Avoid ACE inhibitors/ARBs if breastfeeding is planned; use hydralazine-nitrate combination instead 1
• Consider bromocriptine (inhibits prolactin) for LVEF <35% to improve recovery, though efficacy remains uncertain with contemporary therapy 1, 5
• Anticoagulation should be considered for LVEF <30% until 6-8 weeks postpartum due to thromboembolism risk 1

Monitoring and Prognosis:

• Approximately 50% of PPCM patients recover LV function within 6 months, which is critical for device/transplant decisions 1
• Repeat echocardiography at 6 months before considering ICD or cardiac resynchronization therapy 1
• Transfer to advanced heart failure center if inotrope-dependent for consideration of mechanical circulatory support 1

Critical Pitfalls to Avoid

• Do not dismiss as "just pneumonia" when cardiac dysfunction is present—PPCM can develop rapidly and be fatal 1, 7
• Do not delay diagnosis waiting for "classic" presentation—symptoms overlap with normal pregnancy physiology, causing diagnostic delays 1, 7
• Do not rush to device implantation—wait 6 months given high spontaneous recovery rate unlike other cardiomyopathies 1
• Do not overlook the postpartum period—PPCM can present up to 5 months after delivery 7, 5