A 29-year-old woman was admitted to our hospital because of persistent breathlessness on exertion after the delivery of her second child. Although at the age of 26 she had been given a diagnosis of multiple pulmonary arteriovenous fistula (PAVF), treatment was not done because of the absence of symptoms. An intrauterine growth retardation (IUGR) due to hypoxemia occurred during the second pregnancy, and then she delivered a 1,283g baby by cesarean section in the 36th gestation week. Her symptoms and hypoxemia improved after transcatheter embolization. Hereditary hemorrhagic telangiectasia was diagnosed on the basis of recurrent epistaxis since her childhood, pulmonary and hepatic vascular abnormality (PAVF and hepatic arterioportal shunt) and telangiectasis of the buccal mucosa and tongue. We should consider an early treatment of PAVF for young female because pregnancy may induce increase of arteriovenous shunt, fatal hemoptysis, infertility, miscarriage and IUGR.