Optic nerve sonography and ophthalmic artery Doppler velocimetry in healthy pregnant women: an Australian cohort study

Purpose: Maternal ocular sonography offers a window into cerebrovascular and intracranial pressure changes in pregnancy. This study aimed to determine the Doppler velocimetric variables of the ophthalmic artery, and the mean diameter of the optic nerve sheath (ONSD), in an Australian cohort of healthy pregnant women. Methods: A prospective observational cohort study of healthy women with uncomplicated singleton pregnancies in the third trimester was undertaken in a tertiary maternity service. A single prenatal ultrasonographic examination was performed on all participants, with a postnatal examination performed on a subgroup with uncomplicated deliveries. Results: Fifty women were examined at a mean gestation of 35 weeks. The mean ± SD Doppler variables in the ophthalmic artery were peak systolic velocity (PSV) 41.89 ± 13.13 cm/s, second peak velocity 20.63 ± 8.97 cm/s, end diastolic velocity 9.29 ± 5.13 cm/s, pulsatility index 1.97 ± 0.53, resistive index 0.78 ± 0.07, peak ratio (second peak velocity/PSV) 0.49 ± 0.12, while the mean ONSD was 4.34 ± 0.4 mm. None of these variables had a demonstrable relationship with gestation or mean arterial pressure (MAP), nor did the sheath diameter have a relationship with any of the Doppler variables. Conclusions: The ocular sonographic variables observed in this population are similar to those reported in other cohorts. No clear relationship could be identified in this cohort between ophthalmic artery Doppler variables and the ONSD, and between each of these variables and gestation or MAP.