Women who delivered preterm infants have excess cardiovascular disease, but vascular pathways linking these conditions are not understood. We considered that higher blood pressure over 25 years among women with preterm delivery may be associated with coronary artery calcification (CAC). The CARDIA study (Coronary Artery Risk Development in Young Adults) enrolled 1049 black and white women with births between 1985 and 2010 (n=272 ever preterm [<37 weeks]; n=777 all term births [≥37 weeks]). Latent mixture modeling identified blood pressure trajectories across 20 years, and these were related to CAC at years 20 and 25. Three systolic blood pressure (SBP) patterns were identified: low stable (n=563; 53%), moderate (n=416; 40%), and moderate increasing (n=70; 7%). Women with moderate-increasing SBP were more likely to have delivered preterm compared with those in the low-stable group (40% versus 21%; P<0.0001), and they were more likely to have CAC (38.5% versus 12.2%). The SBP and CAC association varied by preterm birth (P interaction=0.04). Women with preterm delivery and a moderate-increasing SBP had a 2.17-fold higher hazards of CAC (95% confidence interval, 1.14-4.12) compared with women with term births and a lower SBP pattern, adjusted for cardiovascular disease risk factors and other pregnancy features. There was no excess CAC in women with moderate-increasing SBP and term births (adjusted hazard ratio, 1.02; 95% confidence interval, 0.49-2.14). Associations were stronger in women with hypertensive disorders of pregnancy but also detected in those with normotensive preterm deliveries. Women who deliver preterm infants are more likely to follow a high-risk blood pressure pattern throughout the childbearing years that is associated with CAC at midlife.