Aetiology and risk factors of peripartum cardiomyopathy: A systematic review

BackgroundPeripartum cardiomyopathy (PPCM) is a disorder of unknown aetiology in which heart failure due to left ventricular dysfunction occurs between the last month of pregnancy and first five months post-partum. Theories abound concerning the specific cause and risk factors for PPCM, but none have been accepted universally. The primary objective of this review was to summarize the state of knowledge on the pathogenesis of PPCM, especially in light of recent studies.MethodsWe searched MEDLINE (January 1966–September 2007), OVID, and reference lists of articles for studies containing information on the aetiology and risk factors for PPCM, and published in English.ResultsThe literature reveals a wealth of articles proposing various mechanisms for aetiology and risk factors of PPCM. There is conflicting evidence on the pathogenetic role of viral myocarditis, abnormal immune response to pregnancy, abnormal response to the haemodynamic stress of pregnancy, accelerated myocyte apoptosis, cytokine-induced inflammation, malnutrition, genetic factors, excessive prolactin production, abnormal hormonal function, increased adrenergic tone, and myocardial ischaemia. A number of factors are postulated to increase the risk of the development of PPCM. These include non-Caucasian ethnicity, advanced maternal age, multiparity, poor socioeconomic status, multiple pregnancy and prolonged tocolytic use. The authors call for a strict definition of PPCM that excludes known causes of heart failure, such as the pregnancy-induced hypertensive spectrum of disorders.ConclusionThe aetiology and risk factors for PPCM are poorly defined. There is a need for large-scale multi-centre epidemiological studies and registries to delineate the aetiology and pathogenesis of PPCM.