The placental origins of sudden cardiac death.

Most sudden cardiac deaths are due to cardiac arrhythmias, and abnormalities in the autonomic nervous system could underlie them. There is growing evidence that coronary heart disease is associated with alterations of fetal development as a result of variations in the processes of placentation that control fetal nutrition. We hypothesized that placental size would be associated with sudden cardiac death. We examined sudden cardiac death within the Helsinki Birth Cohort of 13 345 men and women. One hundred eighty-seven (2.7%) men and 47 (0.7%) women had sudden unexplained cardiac death outside hospital. Sudden death was associated with a thin placenta, the hazard ratio being 1.47 [95% confidence interval (CI) 1.11-1.93, P = 0.006] for each g/cm(2) decrease in thickness. Sudden death was independently associated with poor educational attainment (P < 0.0001). Both of these associations were independent of socio-economic status in later life. Sudden death may be initiated by impaired development of the autonomic nervous system in utero as a result of shallow invasion of the spiral arteries in the maternal endometrium and consequent fetal malnutrition.