TYPE: Abstract Publication TOPIC: Disorders of the Pleura PURPOSE: Primary spontaneous pneumothorax (PSP) during pregnancy is a rare condition with serious risks to the mother and the fetus, so rapid recognition and treatment are essential. Since few cases has been described, symptoms of dyspnea and chest pain can be easily misdiagnosed. The aim is to describe a case of a pregnant patient with PSP, managed with chest tube drainage. METHODS: A 30-year-old woman on 28th gestational week (gravida 1/ parity 0), non-smoker, presented at urgency department with sudden pleuritic chest pain and dyspnea. No history of respiratory pathology or trauma. On physical examination, hemodynamically stable, no fever, tachypneic with oxygen saturation 97% on ambient air. Pulmonary auscultation with decreased vesicular murmur on the left hemithorax. No analytic alterations. No fetal distress. The chest radiography showed findings of large left pneumothorax, without mediastinum deviation. A chest drain was placed with reduction of pneumothorax. Given the absence of pulmonary re-expansion, suction treatment was made. RESULTS: The patient had progressive recovering and was hospital discharged asymptomatic. A caesarean section was performed on 39th gestational week, under epidural anesthesia, without complications. The patient maintains a pulmonology follow-up, without new episodes of pneumothorax. CONCLUSIONS: PSP during pregnancy should be part of chest pain and dyspnea differential diagnosis and promptly recognized to prevent severe complications. CLINICAL IMPLICATIONS: Given the symptomatic large pneumothorax, a chest tube was placed. Since the high risk of recurrence during delivery, it is recommended elective assisted delivery with forceps or ventouse extraction to lessen maternal efforts, despite some authors consider the caesarean section a safe option. DISCLOSURE: No significant relationships. KEYWORDS: pneumothorax, pregnancy