A particularly dangerous condition in pregnant women is already dilated left ventricle with severe functional impairment. Taking as an example the case of woman with dilated cardiomyopathy (DCM) first diagnosed in 17th week of pregnancy, the paper discusses diagnostic, therapeutic challenges and management of heart failure during pregnancy. Repeat measurements of brain natiuretic peptide levels should be helpful in diagnosing heart failure. To distinguish DCM from peripartum cardiomyopathy the time of manifestation should be considered. The risk of serious events is associated with NYHA class and impairment of left ventricular ejection fraction. Angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin-II receptor blockers are contraindicated in pregnancy because of fetal toxicity. The incidence of sight effects is associated with time of administration of ACE-I and duration of treatment. Possible sight effects of drugs in fetus should be monitored (mainly ultrasonographically). ICD can be implanted during pregnancy if indicated. To assess the time and mode of delivery, a multidisciplinary team of different specialists is required. Subsequent pregnancy is contraindicated in a patient with DCM and low ejection fraction of left ventricle.