Preeclampsia (PE) is characterized by the new onset of hypertension (HT) and proteinuria beyond the 20th week of gestation. We aimed to find the best predictor of PE and find out if it is different in women with or without HT. Consecutively attended pregnant women were recruited in the first trimester of pregnancy and followed-up. Laboratory and office and 24 h-ambulatory blood pressure (BP) data were collected. PE occurred in 6.25% of normotensives (n = 124). Both office mean BP and 24 h-systolic BP in the first trimester were higher in women with versus those without PE (p ≤ 0.001). In women with chronic hypertension (cHT), PE occurred in 55%; office SBP (p = 0.769) and 24 h-SBP (p = 0.589) were similar between those with and those without PE. Regarding biochemistry, in cHT, plasma urea and creatinine were higher in PE women than in those without cHT (p = 0.001 and p = 0.004 for the differences in both parameters). These differences were not observed in normotensives. In normotensives, mean BP was the best predictor of PE [ROC curve = 0.91 (95%CI 0.82-0.99)], best cut-off = 80.3 mmHg. In cHT, plasma urea and creatinine were the best predictors of PE, with ROC curves of 0.94 (95%CI 0.84-1.00) and 0.93 (95%CI 0.83-1.00), respectively. In the first trimester of pregnancy, the strongest predictor of PE in normotensive women is office mean BP, while in cHT, renal parameters are the strongest predictors. Otherwise, office BP is non-inferior to 24 h ambulatory BP to predict PE.
Keywords: ambulatory blood pressure monitoring; chronic hypertension; office blood pressure; predictive factors; preeclampsia.