Preterm Delivery and Cardiovascular Health in Women of Reproductive Age

Pregnancy is considered a stress test for cardiovascular risk in women of childbearing age. Women who experience preterm delivery are seen as failing to adapt to the dramatic physiological changes during pregnancy (i.e., increased insulin resistance, increased triglycerides, and increased cardiac output with accompanying reduced systemic vascular resistance and blood pressure) and have been found to have a higher risk of cardiovascular disease (CVD) later in life. However, the mechanisms linking these two conditions remain unclear. Accumulating evidence indicates that preterm delivery is associated with cardiometabolic risk factors before, during, and after pregnancy, suggesting a shared pathway between preterm delivery and CVD. My dissertation uses longitudinal data to explore why preterm delivery is associated with an elevated risk for CVD from a life course perspective, considering traditional cardiometabolic risk factors at different periods relative to pregnancy. In the first paper, I investigated whether the unfavorable changes in the cardiometabolic profile associated with preterm delivery begin before, during, or after childbearing. I found that preterm delivery was associated with unfavorable patterns of change in diastolic blood pressure and adiposity that originate during the childbearing years and persist or worsen later in life. In the second paper, I examined how cardiometabolic risk factors and preterm delivery relate to coronary artery calcification. Compared to women with term delivery, impaired fasting glucose and elevated blood pressure are more detrimental to the development of subclinical atherosclerosis among those with preterm delivery. In the third paper, I tested the hypothesis that changes in blood lipids from during pregnancy to years after pregnancy may vary based on delivery outcomes. I found that women with spontaneous preterm delivery experience blunted changes in lipids from mid- to post-pregnancy, potentially reflecting impaired ability to adapt and recover from pregnancy. By examining cardiometabolic risk factor changes across different periods relative to pregnancy, this dissertation enhances our understanding of the mechanistic pathways between preterm delivery and future maternal CVD. This is of public health significance because women with a history of preterm delivery could benefit from closer monitoring of cardiometabolic risk factors for better risk stratification and preventative intervention for early CVD.