Reference Ranges of Maternal Ophthalmic Artery Doppler in Low-Risk Pregnancies

To establish reference ranges for Doppler indices of the maternal ophthalmic artery in low-risk pregnancies during the second and third trimesters.

This retrospective cross-sectional study included 358 low-risk pregnancies between 20 and 41 weeks of gestation. Doppler ultrasound of the maternal ophthalmic artery was performed, and the following indices were calculated: pulsatility index (PI), resistance index (RI), peak systolic velocity (PSV), second peak systolic velocity (P2), end diastolic velocity (EDV), and the ratio between peak systolic velocities (PR). Polynomial regression analysis was used to model the fit of a polynomial equation for each Doppler index as a function of gestational age. The 5th, 50th, and 95th percentiles were determined for each gestational age interval.

A significant negative correlation was observed between gestational age and RI (r = -0.11, p = .025) and PSV (r = -0.219, p = .0003), while a significant positive correlation was found between gestational age and PR (r = 0.14, p = .007). No significant correlations were observed between gestational age and PI, P2, or EDV. Reference intervals for each Doppler index were established according to gestational age, providing the 5th, 50th, and 95th percentiles.

This study provided reference intervals for Doppler indices of the maternal ophthalmic artery in low-risk pregnancies during the second and third trimesters. These reference values may aid in the interpretation and clinical application of Doppler findings, particularly in the context of predicting and monitoring preeclampsia.