Ophthalmic artery Doppler: reference values in low-risk pregnant women

Ophthalmic artery (OA) Doppler has been described as an independent parameter in predicting preeclampsia (PE). Considering that vasoconstriction occurs in the pathogenesis of PE and causes increased pulse wave reflection, it is not surprising that OA waveform changes appear in PE. It was found that of these waveform changes, the 2nd systolic peak (P2) and the peak ratio [PR = P2/P1 (P1 = 1st systolic peak)] showed the best performance in prediction and complementary diagnosis of PE. The aim of this study was to determine reference values for OA-Doppler indices in the 1st, 2nd, and 3rd trimesters and at term in low-risk pregnant women of a mixed European population.

This is a prospective single-center cohort study conducted from 2020 to 2024. Only healthy pregnant women who gave informed consent were included. Women at high risk for PE or who developed PE were excluded. OA Doppler was performed according to a strict protocol at 4 distinct gestational-week (GW) intervals: 11-14 GW, 20-24 GW, 30-34 GW, and at term. The following systolic waveform parameters were focused on: P1, P2, and PR. Reference values were generated for these waveform parameters for these study intervals in the 1st, 2nd, and 3rd trimesters and at term.

A total of 255 women were included in this study. Of these, 62% were Caucasian, 7% Asian, 8% Afro-Caribbean, and 33% mixed or of unknown ethnicity. In this population, the PR averaged over the study intervals was 0.56, with no significant differences between the 4 study intervals or between the right and left eyes.

This study presents systolic OA-Doppler reference values in low-risk pregnant women of an ethnically diverse European tertiary-care obstetric population. OA-Doppler reference values are stable throughout the four selected time points in pregnancy. These findings may pave the way for further investigations on OA-Doppler values as a predictive and diagnostic tool for PE.