Haptoglobin phenotype, angiogenic factors, and preeclampsia risk.

OBJECTIVE: We sought to determine whether haptoglobin (Hp) phenotype is related to preeclampsia risk, or to plasma concentrations of soluble endoglin (sEng), soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF). STUDY DESIGN: Hp phenotype was retrospectively determined in primiparous women with uncomplicated pregnancies (n = 309), gestational hypertension (n = 215), and preeclampsia (n = 249). Phenotype was assessed by peroxidase staining following native polyacrylamide gel electrophoresis of hemoglobin-supplemented serum. RESULTS: Compared with Hp 1-1, Hp 2-1 was associated with a significantly increased risk of preeclampsia (odds ratio, 2.11; 95% confidence interval, 1.07-4.18) and term preeclampsia (odds ratio, 2.45; 95% confidence interval, 1.07-5.83) in Caucasian women. Hp phenotype was not associated with preeclampsia risk in African Americans. Preeclamptic women had higher plasma sEng and sFlt-1, and lower PlGF, than control subjects. sEng, sFlt-1, and PlGF did not differ among women of different Hp phenotypes. CONCLUSION: Hp 2-1 is associated with higher preeclampsia risk in primiparous Caucasian women.