Pulmonary arteriovenous malformations (PAVM) expand during pregnancy because of increases in blood volume, cardiac output, and venous distensibility. More than half of the cases reported during pregnancy are associated with hereditary telangiectasia. In this case a 36-year-old primigravida presented at 24 weeks of gestation with new onset hemoptysis and dyspnea. A PAVM was noted in the right lower lobe during angiography and was successfully treated with embolization. Recurrence of symptoms occurred at 36 weeks of gestation after recanalization of the PAVM. Cesarean delivery was performed because of both this recurrence and breech presentation. The patient's symptoms subsequently resolved after delivery. The patient underwent a segmentectomy without complication 6 months after delivery. Thus, women with known PAVM or a history of hereditary telangiectasia should be followed with serial chest roentgenograms and arterial blood gases to detect acute progression of the PAVM. Embolization can be used during pregnancy if the PAVM is symptomatic.