Atrial septal defect (ASD) is the most common congenitalheart disease in adulthood. Although usually clinically asymptomaticin adult patients, it may become symptomaticwith rhythm disorders and shortness of breath. Prognosisof pregnancy with congenital heart disease and health ofinfant were affected by several factors such as location ofcardiac defect, presence or absence of cyanosis, degreeof pulmonary vascular resistance, hemoglobin level, functionalcapacity and history of surgical repair. In this case,we presented a 29 years old, 15 weeks pregnant womenwith previously unknown congenital heart disease whohad complaints of shortness of breath and palpitations. Inphysical examination, we found a grade 2/6 systolic murmuron mezocardiyak focus and 3/6 on tricuspid focus.Transthoracic echocardiography showed secundum typeASD (3 cm), severe right ventricular enlargement, moderatetricuspid regurgitation and increased pulmonary arterysystolic pressure (60 mmHg). Pregnancy was terminatedand the ASD was occluded surgically in elective conditions.J Clin Exp Invest 2011; 2 (4): 452-454