Reference values of maternal ophthalmic artery doppler variables in the first trimester of normal pregnancy

Background: The aim of this study was to establish normative data for ophthalmic artery Doppler variables in the first trimester of normal pregnancy.

Methods: Maternal ophthalmic artery Doppler signals were recorded in 409 singleton pregnancies at 11-14 weeks' gestation, in mothers presenting consecutively for routine antenatal care. Pulsatility and resistance indices (PI, RI), peak systolic velocity (PSV), first peak diastolic velocity (PD1), and peak ratio (PR) were measured. Quartile regression was used to estimate reference ranges in the late first trimester of pregnancy.

Results: Mean ± SD values for maternal ophthalmic artery Doppler parameters between 11 and 14 weeks' gestation were RI = 0.81 ± 0.12, PI = 2.06 ± 0.57, PSV = 36.41 ± 12.1, PD1 = 21.07 ± 7.62, and PR = 0.58 ± 0.11. All clinical and Doppler variables were normally distributed. PD1 values were higher in patients who smoked, and in those with diabetes or a history of pre-eclampsia. PR values were higher in patients with diabetes and chronic hypertension, and lower in the nulliparous; these values declined as gestation advanced from 11 to 14 weeks, whereas the other variables remained unchanged.

Conclusions: We provide reference values for maternal ophthalmic artery Doppler variables in the first trimester of normal pregnancy.