Objective To investigate perinatal predictors of newborn blood pressure. Study design Among 1059 mothers and their newborn infants participating in Project Viva, a US cohort study of pregnant women and their offspring, we obtained five systolic blood pressure readings on a single occasion in the first few days of life. Using multivariate linear regression models, we examined the extent to which maternal age and other pre- and perinatal factors predicted newborn blood pressure level. Results Mean (SD) maternal age was 32.0 (5.2) years, and mean (SD) newborn systolic blood pressure was 72.6 (9.0) mm Hg. A multivariate model showed that for each 5-year increase in maternal age, newborn systolic blood pressure was 0.8 mm Hg higher (95% CI, 0.2, 1.4). In addition to maternal age, independent predictors of newborn blood pressure included maternal third trimester blood pressure (0.9 mm Hg [95% CI, 0.2, 1.6] for each increment in maternal blood pressure); infant age at which we measured blood pressure (2.4 mm Hg [95% CI 1.7, 3.0] for each additional day of life); and birth weight (2.9 mm Hg [95% CI, 1.6, 4.2] per kg). Conclusions Higher maternal age, maternal blood pressure, and birth weight were associated with higher newborn systolic blood pressure. Whereas blood pressure later in childhood predicts adult hypertension and its consequences, newborn blood pressure may represent different phenomena, such as pre- and perinatal influences on cardiac structure and function. Development of risk for adult cardiovascular disease begins very early in life, even before birth.1 Data are scarce, however, regarding blood pressure in the newborn period, which may reflect pre- and perinatal influences on cardiac structure and function. The few studies that have examined determinants of newborn blood pressure suggest a direct association with birth weight,2.; 3.; 4.; 5.; 6.; 7.; 8.; 9. ; 10. in contrast to the inverse association seen with older infants, children, and adults.11 However, most of these studies have at least one important limitation, such as a relatively small sample size of term newborns, lack of data on potentially confounding variables, and limited data on maternal predictors. Maternal age is of particular interest given the known associations of advanced age with adverse reproductive outcomes, including reduced fertility, preterm birth, impaired fetal growth, multiple birth, and congenital anomalies.12.; 13. ; 14. The additional associations of advanced maternal age with diabetes and hypertension,15. ; 16. with possible diminished uterine vascular and placental function,17. ; 18. and in at least two reports with blood pressure level in childhood and in adolescence19. ; 20. warrant examination of its influence on newborn blood pressure. The purpose of this analysis was to investigate associations of pre- and perinatal factors, including maternal age, with systolic blood pressure level during the first few days of life among members of Project Viva, a cohort study of pregnant women and their children.