To determine values for home blood pressure (HBP) during pregnancy, nurses taught 45 healthy pregnant women to use a HBP method for 1 week before 15 weeks of gestation, between weeks 15 and 27, and after 28 weeks for the last 3 months of gestation. HBP values were significantly lower during the second trimester and higher during the last trimester (102 +/- 8/59 +/- 7*, 101 +/- 8/57 +/- 8*, 105 +/- 8*/62 +/- 9* mm Hg;*P< 0.05) than during other trimesters. Heart rate increased significantly during the pregnancy. The present study suggests upper limits for HBP: 118/73, 117/73, and 121/80 mm Hg, respectively during the 3-month gestational periods. These findings may be helpful in providing clinicians with comparative values so as begin to establish reference values for HBP during pregnancy.