Objective: To determine whether a rise in systolic blood pressure (SBP) > or = 30 mm Hg and/or diastolic blood pressure (DBP) > or = 15 mm Hg in the absence of hypertension during pregnancy is associated with adverse pregnancy outcomes.
Method: We conducted a retrospective, longitudinal study of 1,498 pregnant women without hypertension or proteinuria in the first trimester. The blood pressure levels measured during the first (7.8 +/- 2.3 weeks), second (20.7 +/- 1.2 weeks), and third trimesters (38.6 +/- 1.5 weeks) were analyzed. The perinatal outcome was compared between women who exhibited a rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg during pregnancy (large Delta BP group) and women who did not (small Delta BP group) using one way analysis of variance, chi-square test, or Fisher's exact test. The contribution of gestational hypertension and a large Delta BP to the development of adverse pregnancy outcomes was evaluated using multivariate logistic regression analysis.
Results: Of 1441 women who remained normotensive (SBP < 140 mm Hg and DBP < 90 mm Hg) during pregnancy, 238 (16.5%) and 1,203 (83.5%) belonged to the large Delta BP and small Delta BP groups, respectively. There were no significant differences between the two groups in the occurrence rate of gestational proteinuria, preterm deliveries, low-birth-weight infants, or small-for-gestational age infants. A large Delta BP was not a risk factor in itself for the occurrence of gestational proteinuria or small-for-gestational age infants after controlling for the effect of gestational hypertension.
Conclusion: A rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg is not a risk factor of adverse outcome among women who remain normotensive during pregnancy.