Objective: The objective of our study was to clarify the effect of the maternal prone position on the feto-placental flow. In this position, the uterine compression of the large maternal vessels was expected to be completely eliminated.
Methods: Twenty-three normal pregnant women were cross-sectionally examined in the supine, the left lateral, the right lateral and the prone position. The systolic/diastolic ratios for the umbilical artery were calculated for each position.
Results: The umbilical arterial systolic/diastolic ratio in the prone position significantly decreased compared with that in the supine position. The left and right lateral position showed no significant change in the systolic/diastolic ratio.
Conclusion: The maternal prone position can provide complete relief of uterine compression of the large maternal vessels.