Racial-ethnic Differences in Midtrimester Maternal Serum Levels of Angiogenic and Antiangiogenic Factors

Background: Little is known about racial-ethnic differences in the distribution of maternal serum levels of angiogenic and antiangiogenic factors and their associations with early-onset preeclampsia.

Objective: We sought to investigate the distribution of midtrimester maternal serum levels of placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1 and their associations with early-onset preeclampsia in whites, Hispanics, and blacks.

Study Design: A population-based nested case-control design was used to identify cases and controls of white, Hispanic, and black origin from a 2000 through 2007 live-birth cohort in 5 southern California counties. Cases included 197 women (90 whites, 67 Hispanics, and 40 blacks) with early-onset preeclampsia defined as hypertension and proteinuria with onset <32 weeks according to hospital records. Controls included a random sample of 2363 women without early-onset preeclampsia. Maternal serum specimens collected at 15-20 weeks' gestation as part of routine prenatal screening were tested for placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1. Serum levels of the 3 factors were log-normally distributed. Adjusted natural logarithmic means were compared between cases and controls and between racial-ethnic groups. Odds ratios and 95% confidence intervals derived from logistic regression models were calculated to measure the magnitude of the associations.

Results: Cases showed lower adjusted logarithmic means of placental growth factor but higher adjusted logarithmic means of soluble endoglin than controls across all 3 groups (P < .05). Cases also had higher adjusted means of soluble vascular endothelial growth factor receptor 1 than controls in whites (7.75 vs 7.52 log pg/mL, P < .05) and Hispanics (7.73 vs 7.40 log pg/mL, P < .05) but not in blacks (7.85 vs 7.69 log pg/mL, P = .47). Blacks were found to have higher levels of placental growth factor in both cases and controls when compared to whites and Hispanics (adjusted means: 4.69 and 5.20 log pg/mL in blacks, 4.08 and 4.78 log pg/mL in whites, and 3.89 and 4.70 log pg/mL in Hispanics, respectively, P < .05). Hispanic cases had the highest adjusted mean of soluble endoglin compared to white and black cases (9.24, 9.05, and 8.93 log pg/mL, respectively, P < .05). The weakest association of early-onset preeclampsia with placental growth factor and soluble endoglin was observed in blacks. The adjusted odds ratio per log pg/mL increase of the 2 analytes were 0.219 (95% confidence interval, 0.124-0.385) and 5.02 (95% confidence interval, 2.56-9.86) in blacks in comparison to 0.048 (95% confidence interval, 0.026-0.088) and 36.87 (95% confidence interval, 17.00-79.96) in whites (P < .05) and 0.028 (95% confidence interval, 0.013-0.060) and 86.68 (95% confidence interval, 31.46-238.81) in Hispanics (P < .05), respectively. As for soluble vascular endothelial growth factor receptor 1, the association was not significantly different among the racial-ethnic groups.

Conclusion: Racial-ethnic differences were observed in the distribution of midtrimester maternal levels of placental growth factor and soluble endoglin and in the associations with early-onset preeclampsia. These differences should be considered in future studies to improve etiologic and prognostic understanding of early-onset preeclampsia.