Effects of Right Lateral Position on Changes of Fetal Hemodynamics in Late Pregnancy

We aim to evaluate the effect of right lateral position on fetal hemodynamics (including umbilical artery [UA] and middle cerebral artery (MCA) blood flow-velocity waveform).

In total, 150 low-risk singleton full-term pregnant women were included in the study from November 2021 to January 2022. Doppler flow velocity waveforms of the fetal UA and MCA tested by ultrasound were collected in gestation of 37-40 weeks. Computational analysis was performed using the one-way ANOVA test.

Compared with the maternal left lateral position, there was a significant increase in Doppler indices of UA-RI (P = .033), UA-S/D (P = .019) and MCA-PSV (P = .021) and a significant decrease in MCA-RI (P = .030) in the supine position group. There was no statistical significance in all Doppler indices between the left and right lateral position (P > .05). Among the Doppler indices of three different maternal positions, there was no significance in both UA-PI and MCA-PI (P > .05).

There were no significant differences on changes of the fetal hemodynamics between left and right lateral positions. Pregnant women could adopt to lie in the left or right lateral position alternately to relieve the discomfort in late pregnancy.