Effect of Maternal Rest and Resting Positions on Amniotic Fluid

Plain-language summary

Maternal rest in left lateral decubitus position increases fetal urine production rate which in turn increases the estimated amniotic fluid volume (AFV) in uncomplicated pregnancies. The estimated AFV increases faster at initial periods, particularly during the first, second and third 15 minute periods of the maternal rest in the left lateral position. Although at each successive 15 minute period the estimated AFV continues to increase, the increase rate is always less in the following period. The AFV increase curve resembles the characteristics of a saturation curve and finally the estimated AFV increase stops approximately at the second hour. Although maternal rest in left lateral decubitus position increased the estimated AFV in the previous studies, the sole effect of left lateral position or the sole effect of rest was not evaluated, and the results of resting in another position is not known. In addition, it is hard for a pregnant woman to maintain the left lateral position continuously. Rest in the prone position is not practical for a pregnant woman, particularly after the first trimester of the pregnancy and supine position may cause several hypotension related symptoms including nausea, anxiety, lightheadedness, shortness of breath, perspiration, tachycardia and urge to change position. Thus, right lateral position may be an alternative. The purpose of this study is to analyze the effect of maternal rest in the right lateral decubitus position on estimated amniotic fluid volume in comparison with the left lateral position. Because, in both groups the mothers rested, our secondary aim was to obtain data for the contribution of maternal rest to the AFI increase observed in the previous studies.

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