Correlation between the duration of maternal rest in the left lateral decubitus position and the amniotic fluid volume increase.
ABSTRACT The purpose of this study was to show the relationship between amniotic fluid volume changes and the duration of maternal rest in the left lateral decubitus position.
Pregnant women (n = 34) with an amniotic fluid index between 6 and 24 cm and an uncomplicated singleton pregnancy at 35 to 40 weeks' gestation were included in the study. After the initial amniotic fluid index measurements, the women were instructed to rest in the left lateral position, and the measurements were repeated at 15, 30, 45, 60, 75, and 90 minutes.
The amniotic fluid index increased at each sequential interval. Although each amniotic fluid index value was higher than the preceding one, only the 15- and 30-minute values were significantly higher than the preceding measurements (P < .001; P < .01, respectively). At the beginning of maternal rest in the left lateral position, 15 minutes of rest was sufficient to create significant changes (P < .001). However, after 30 minutes of rest, an additional 45 minutes was needed to create a significant amniotic fluid index increase (P < .01). The curve describing the amniotic fluid index increases caused by maternal rest resembled a saturation curve, and the maximum increase in the amniotic fluid volume was projected to be achieved approximately at the end of the second hour of the rest period.
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).
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ABSTRACT: The purpose of this study was to determine the effect of the maternal left lateral decubitus position and rest on the fetal urine production rate. Fifty-four pregnant women with a normal amniotic fluid volume who had a singleton pregnancy between 26 and 40 weeks' gestation were included in this prospective study. Exclusion criteria included rupture of membranes, intake of any food or liquid within the previous 4 hours, and maternal or fetal complications. The amniotic fluid index was determined by averaging 2 or 3 repetitive measurements of the 4 amniotic fluid quadrants at the time of fetal urinary bladder volume measurements. The fetal urine production rate was measured using virtual organ computer-aided analysis. The amniotic fluid index and fetal urine production rate before and after the left lateral position rest period were compared by a paired Student t test. The Pearson correlation was used to study the relationships among the maternal age, gestational age, test time, amniotic fluid index, and fetal urine production changes. The mean amniotic fluid indices ± SD before and after the rest period were 151.0 ± 45.0 and 172.5 ± 46.7 mm, respectively, indicating a significant increase in the amniotic fluid index (P < .05). The mean fetal urine production rates before and after the rest period were 73.7 ± 66.8 and 151.8 ± 119.9 mL/h, respectively, indicating a significant increase in fetal urine production (P < .05). The fetal urine production rate and amniotic fluid index are markedly increased by maternal rest in the left lateral decubitus position.Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 04/2011; 30(4):481-6. · 1.40 Impact Factor