Factors affecting blood pressures in newborn infants.

Blood pressure (BP) was measured in 837 newborn infants ranging in age from 1-6 days and their mothers in Boston, Massachusetts, and Providence, Rhode Island. The BP increased significantly with age in days, birth weight, weight on day of measurement, arm circumference, and ponderal index. There was no relation of sex, race, pulse rate, type of feeding, or Apgar scores to BP in the neonatal period. Significant correlation was found between maternal and infant BP (r = 0.196 for systolic (SBP) and 0.157 for diastolic (DBP) pressures, p < 0.001). Preliminary analysis shows a trend for resemblance of 1-month and newborn BP.