When does pericardium cardiomyopathy start in pregnancy and how long does it last?

Peripartum. Read this about peripartum(not pericardium) cardiomyopathy en.Wikipedia.Org/wiki/peripartum_cardiomyopathy.
During or after. Peripartum cardiomyopathy (ppcm) is an uncommon disorder associated with pregnancy in which the heart dilates and weakens, leading to symptoms of heart failure. Affected women may recover normal heart function, may stabilize on medicines, or may progress to severe heart failure. The duration varies.