Risk Factors of Superimposed Preeclampsia in Women with Essential Chronic Hypertension Treated before Pregnancy

OBJECTIVE To determine risk factors of superimposed preeclampsia in women with essential chronic hypertension receiving antihypertensive therapy prior to conception. METHODS A retrospective study of 211 patients that analyzed risk factors of superimposed preeclampsia at first prenatal visit. Variables with a p<.1 at univariate analysis were included in a logistic regression analysis. P<.05 was considered as significant. RESULTS Superimposed preeclampsia occurred in 49 (23.2%) women. In logistic regression analysis, previous preeclampsia [OR: 4.05 (1.61-10.16)], and mean arterial blood pressure of 95 mmHg or higher [OR: 4.60 (1.94-10.93)] were associated with increased risk of superimposed preeclampsia. When both variables were present, sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio for superimposed preeclampsia were 43%, 94%, 70%, 85%, and 7.71 (95% CI: 3.20-18.57), respectively. CONCLUSION In essential chronic hypertensive women, previous preeclampsia and mean arterial blood pressure of 95 mmHg or higher are associated with increased risks of superimposed preeclampsia.