Parameters associated with adverse perinatal outcome in hypertensive pregnancies

Abstract

Background: Hypertensive disorders are a major contributor to perinatal morbidity and mortality. As all hypertensive pregnancies do not have a bad outcome, we sought to identify clinical and laboratory parameters associated with adverse perinatal outcome in hypertensive pregnancies.

Methods: We analyzed the clinical course of 271 hypertensive patients delivered at a tertiary center. Adverse perinatal outcome included: (1) perinatal death; and (2) perinatal morbidity due to hypertension-related prematurity and uteroplacental vasculopathy. In our analysis, we sought to compare good and adverse perinatal outcome groups of hypertensive pregnancies. Two sample t-tests were used for continuous variables and chi 2-tests were performed for categoric variables. Blood pressures (BP) were analyzed by multivariate analysis for four time periods (P, I through IV) defined by gestational age in weeks: I, 10-19; II, 20-24; III, 25-29; and IV, 30-36.

Results: There were 96 cases of adverse perinatal outcome due to hypertension (mortality, n = 6; morbidity, n = 90) in this series. Two clinical factors had a significant association with adverse perinatal outcome: (1) the need for prenatal treatment with antihypertensives (P < 0.0001); and (2) early onset of hypertension during the pregnancy (P < 0.008). The adverse outcome group had higher systolic (S) BP as early as 10-19 weeks (P < 0.01). This group had higher systolic and diastolic (D) BP as early as 20-24 weeks' gestation (P < 0.004-0.0001). Serum uric acid of > or = 6 mg/dl had a relative risk of 4.2 for adverse perinatal outcome (95% CI, 2.0-8.9; P < 0.0001).

Conclusions: Our study suggests that the increased severity and longer duration of hypertension may be the primary pathophysiologic mediator of adverse perinatal effects in these pregnancies. Elevated serum uric acid may be a clinically useful predictor of perinatal mortality and, more importantly, of perinatal morbidity in hypertensive pregnancies.