The effect of various levels of both diastolic and systolic blood pressure at various times during pregnancy on the rates of intrauterine growth retardation (IUGR) and preterm delivery (PTD) were determined. Low systolic and diastolic pressures were associated with both IUGR and PTD, as were high pressures. Low pressures tended to be associated with spontaneous preterm deliveries, whereas high pressures were associated with more indicated preterm deliveries. © 1992, Cambridge University Press. All rights reserved.