Haptoglobin phenotype and abnormal uterine artery Doppler in a racially diverse cohort

Abstract

Objective: The anti-oxidant and proangiogenic protein haptoglobin (Hp) is believed to be important for implantation and pregnancy, although its specific role is not known. The three phenotypes (1-1, 2-1 and 2-2) differ in structure and function. Hp 2-2 is associated with increased vascular stiffness in other populations. We examined whether Hp phenotype is associated with abnormal uterine artery Doppler (UAD) in pregnancy.

Methods: We conducted a secondary analysis of a preeclampsia prediction cohort nested within a larger placebo-controlled randomized clinical trial of antioxidants for prevention of preeclampsia. We determined Hp phenotype in 2184 women who completed UAD assessments at 17 weeks gestation. Women with notching were re-evaluated for persistent notching at 24 weeks’ gestation. Logistic regression was used to assess differences in UAD indices between phenotype groups.

Results: Hp phenotype did not significantly influence the odds of having any notch (p = 0.32), bilateral notches (p = 0.72), or a resistance index (p = 0.28) or pulsatility index (p = 0.67) above the 90th percentile at 17 weeks’ gestation. Hp phenotype also did not influence the odds of persistent notching at 24 weeks (p = 0.25).

Conclusions: Hp phenotype is not associated with abnormal UAD at 17 weeks’ gestation or with persistent notching at 24 weeks.

• Ethnicity
• haptoglobin
• pregnancy
• race
• vascular resistance
• women

Acknowledgements

The authors thank James M. Roberts for his extensive involvement in this project, and the subcommittee members who participated in protocol development and coordination between clinical research centers (Sabine Bousleiman, Margaret Cotroneo), protocol/data management and statistical analysis (Rebecca G. Clifton, Elizabeth Thom), and protocol development and oversight (James M. Roberts, Kenneth J. Leveno, Catherine Y. Spong, Gail D. Pearson).