Placental Weight Relative to Birth Weight and Long-term Cardiovascular Mortality: Findings From a Cohort of 31,307 Men and Women

Birth weight is inversely associated with risk of adult cardiovascular disease, and evidence exists that fetal adaptation to challenges in the intrauterine environment may adversely affect long-term cardiovascular health. The placenta is in a key position to mediate such effects because adequate placental function is necessary for delivery of nutrients, oxygen, and hormones to the fetus. This prospective population study based on data from the hospital birth charts of 31,307 Norwegian men and women born between 1934 and 1959 assessed whether placental weight relative to birth weight was associated with risk of death from cardiovascular disease in adulthood. During 45 years of follow-up, 382 people died from cardiovascular disease (median age, 51.3 years). Results showed that the placenta-to-birth-weight ratio was positively associated with cardiovascular disease mortality; the sex- and cohort-adjusted hazard ratio for the highest versus the lowest third was 1.38 (95% confidence interval: 1.07, 1.77). The authors concluded that a disproportionately large placenta relative to birth weight was associated with increased risk of cardiovascular disease death. This finding suggests that placental function is important in the association of intrauterine factors with cardiovascular disease later in life.