Women with dilated cardiomyopathies (DCM) have traditionally been advised not to attempt to carry pregnancies. This is largely based on data derived from studies of the course of peripartum cardiomyopathy (PPCM) and it is not clear that this extrapolation is appropriate. Our objective was to compare maternal and obstetric outcomes of pregnancies in women with preexisting DCM to women with PPCM. A 10-year retrospective comparative cohort study was undertaken of women between the ages of 15 and 40 discharged from two university medical centers with the diagnosis of cardiomyopathy (CM). Patients were included in the study if CM was diagnosed prior to pregnancy (DCM group) or if CM developed during pregnancy or within 5 months postpartum (PPCM group), and follow-up data was available. Thirty-one subjects were included in the study. Twenty-three women with the diagnosis of PPCM were compared with 8 women with DCM of other etiologies. There were no significant differences in maternal age, race, parity, tobacco or other substance use, or other risk factors between the two groups. Maternal outcomes in the PPCM group were significantly worse than in the DCM group, with three maternal deaths and four women undergoing heart transplants (p = 0.05). In the DCM group, one woman with a prepregnancy ejection fraction of 16% underwent transplantation after termination of pregnancy for genetic indications. None of the other women in the DCM group had a significant decline in cardiac status. Infant outcomes in both groups were uniformly good. PPCM represents an acute, evolving insult to the pregnant or postpartum woman. The prognosis of this condition should not be used for counseling women with DCM considering pregnancy. Women with stable DCM may do well during pregnancy without significant deterioration in their cardiac status.