Chronic hypertension in pregnancy: impact of ethnicity and superimposed preeclampsia on placental, endothelial, and renal biomarkers.

Black ethnicity is associated with worse pregnancy outcomes in women with chronic hypertension. Preexisting endothelial and renal dysfunction and poor placentation may contribute, but pathophysiological mechanisms underpinning increased risk are poorly understood. This cohort study aimed to investigate the relationship between ethnicity, superimposed preeclampsia, and longitudinal changes in markers of endothelial, renal, and placental dysfunction in women with chronic hypertension. Plasma concentrations of placental growth factor (PlGF), syndecan-1, renin, and aldosterone and urinary angiotensinogen-to-creatinine ratio (AGTCR), protein-to-creatinine ratio (PCR), and albumin-to-creatinine ratio (ACR) were quantified during pregnancy and postpartum in women with chronic hypertension. Comparisons of longitudinal biomarker concentrations were made using log-transformation and random effects logistic regression allowing for gestation. Of 117 women, superimposed preeclampsia was diagnosed in 21% ( n = 25), with 24% ( n = 6) having an additional diagnosis of diabetes. The cohort included 63 (54%) women who self-identified as being of black ethnicity. PlGF concentrations were 67% lower [95% confidence interval (CI) -79 to -48%] and AGTCR, PCR, and ACR were higher over gestation, in women with subsequent superimposed preeclampsia (compared with those without superimposed preeclampsia). PlGF <100 pg/ml at 20-23.9 wk of gestation predicted subsequent birth weight <3rd percentile with 88% sensitivity (95% CI 47-100%) and 83% specificity (95% CI 70-92%). Black women had 43% lower renin (95% CI -58 to -23%) and 41% lower aldosterone (95%CI -45 to -15%) concentrations over gestation. Changes in placental (PlGF) and renal (AGTCR/PCR/ACR) biomarkers predated adverse pregnancy outcome. Ethnic variation in the renin-angiotensin-aldosterone system exists in women with chronic hypertension in pregnancy and may be important in treatment selection.