Abstract Body (Do not enter title and authors here): Background:
Pericarditis is a rare obstetric complication. Severe pericardial disease may lead to tamponade physiology, jeopardizing both the mother and fetus. We report a case of a 29-year-old woman, G1P0 at 21 weeks gestation, presenting with recurrent pericarditis complicated by early signs of cardiac tamponade.

Methods:
A 29-year-old (G1P0) female with a history of Graves' disease on methimazole, drug-induced lupus, and recent pericarditis presented to the hospital at 21-weeks gestation due to recurrent chest pain. She was recently admitted for pericarditis and placed on aspirin and colchicine. Transthoracic echocardiogram (TTE) revealed a small pericardial effusion with diastolic inversion. Thyroid function tests were elevated, and methimazole was increased to 20 mg daily. The patient remained home for two weeks until developing recurrent positional chest pain. On admission, the patient was hemodynamically stable. EKG revealed sinus tachycardia. Repeat TTE confirmed recurrence of acute pericarditis, now with pericardial thickening, fibrinous material adjacent to the visceral pericardium, and a large 2-centimeter pericardial effusion (Figure 1). Evidence of RV inversion and a plethoric IVC were present, concerning for early tamponade physiology.

Results:
Differential diagnosis at the time was broad, including pericarditis of viral etiology or secondary to drug-induced lupus or Graves disease. Given early tamponade physiology and hemodynamic stability, a multidisciplinary team chose medical management over pericardial window due to ongoing pregnancy, suboptimal window for drainage, and procedure-related risks. Aspirin was started at 650 mg twice a day along with 20 mg methylprednisolone and 0.6 mg colchicine. Intravenous fluid resuscitation was provided to maintain preload. Serial TTE was utilized to monitor the progression of the effusion. Methimazole was maintained at 20 mg daily. Viral and autoimmune pericarditis workup was unremarkable. After two weeks of serial echocardiograms, the patient was gradually tapered to aspirin 81 mg daily, prednisone 15 mg daily, and colchicine 0.6 mg daily and discharged. The rest of her pregnancy was uncomplicated, and she delivered a healthy baby at 38 weeks gestation.

Conclusion:
This case highlights the complexities of managing pericarditis in pregnant patients with autoimmune conditions. Medical management and serial TTE were useful in managing early tamponade while minimizing risks to both the mother and fetus.