Correlation Between the Duration of Maternal Rest in the Left Lateral Decubitus Position and the Amniotic Fluid Volume Increase

Abstract

The correlation between the duration of maternal rest and amniotic fluid volume changes is not linear. However, maternal rest in the left lateral decubitus position significantly increases the amniotic fluid volume, particularly in the first 30 minutes (maximum increase in the first 15 minutes).

Effect of Maternal Hydration on the Amniotic Fluid Volume During Maternal Rest in the Left Lateral Decubitus Position

“…To our knowledge, our study is the first to demonstrate the effect of maternal hydration during rest in the left lateral decubitus position. Our study also showed a significant amniotic fluid index increase during maternal rest in the left lateral decubitus position, as in previous studies 12 – 14 . In this prospective randomized controlled study, both groups were standardized to maternal rest in the left lateral decubitus position, and the only variable that differed was maternal hydration.…”

“…However, oral hydration at 1000 mL/h continued to increase the amniotic fluid volume more rapidly in the hydration group than in the control group after 1 hour of hydration (Figure 1). In addition, in one of the previous studies, 14 only the 15‐ and 30‐minute amniotic fluid index values were significantly higher than the preceding measurements. Our study revealed the same results for the left lateral decubitus position–alone group; however, the 15‐, 30‐, and 45‐minute amniotic fluid index values were significantly higher than the preceding measurements in the hydration group.…”

“…Recent studies demonstrated an increase in the amniotic fluid index during maternal rest in the left lateral decubitus position 12 – 14 . The finding was also correlated with an increased fetal urine production rate 12 .…”

“…We used a computerized program and sealed cards to assign patients into hydration and control groups. For power analysis, we used the amniotic fluid index values obtained in a previous study 14 . Power analysis indicated that to achieve an increase from the initial mean amniotic fluid index ± SD of 156.32 ± 37.82 mm to a 15‐minute amniotic fluid index of 186.95 ± 48.82 mm with 90% of power at a 1‐sided α level of .05, at least 35 women were needed in each group.…”

The most frequent prescription in Obstetrics: Bed Rest!

“…Finally, the amniotic fluid volume increase stops at approximately at the second hour of rest. The maximum increase is in the first fifteen minutes [20]. It may be because the maternal left lateral position, having the least disturbing effect on fetal hemodynamics compared with any other position, [21,22] may increase uterine and placental blood flow.…”