The effects of different maternal positions on non-stress test: an experimental study

Impact of maternal posture on fetal physiology in human pregnancy: a narrative review

In numerous medical conditions, including pregnancy, gravity and posture interact to impact physiology and pathophysiology. Recent investigations, for example, pertaining to maternal sleeping posture during the third trimester and possible impact on fetal growth and stillbirth risk highlight the importance and potential clinical implications of the subject. In this review, we provide an extensive discussion of the impact of maternal posture on fetal physiology from conception to the postpartum period in human pregnancy. We conducted a systematic literature search of the MEDLINE database and identified 242 studies from 1991 through 2021, inclusive, that met our inclusion criteria. Herein, we provide a synthesis of the resulting literature. In the first section of the review, we group the results by the impact of maternal posture at rest on the cervix, uterus, placenta, umbilical cord, amniotic fluid, and fetus. In the second section of the review, we address the impact on fetal-related outcomes of maternal posture during various maternal activities (e.g., sleep, work, exercise), medical procedures (e.g., fertility, imaging, surgery), and labor and birth. We present the published literature, highlight gaps and discrepancies, and suggest future research opportunities and clinical practice changes. In sum, we anticipate that this review will shed light on the impact of maternal posture on fetal physiology in a manner that lends utility to researchers and clinicians who are working to improve maternal, fetal, and child health.

Do different positions during a non-stress test affect the maternofetal physiological parameters and comfort in pregnant women?

BACKGROUND

A non-stress test (NST) is an essential diagnostic test performed during pregnancy to assess fetal well-being. It is a recording of fetal movements besides fetal heart rate, indicating fetal biophysiological well-being. As maternal physiology is altered in various positions, apt positioning during the NST is essential for accurate results while ensuring maternal comfort. This study aims to evaluate the effect of different maternal positions, left lateral and semi-fowler's, on NST reactivity, maternal blood pressure, heart rate, and comfort in pregnant women while performing the NST.

MATERIALS AND METHODS

This crossover study evaluated 50 healthy pregnant women between 32 and 40 weeks of gestation with no obstetric complications for the effect of maternal positions on maternofetal physiological parameters and comfort. The NST was performed for 20 min in each position with a washout period of 10 min. The maternofetal physiological parameters were recorded by a calibrated sphygmomanometer and the electrocardiograph interpretations. The maternal comfort was assessed using a maternal comfort rating scale (MCRS) for each position after the NST. Relevant descriptive and inferential statistics are applied to compute the results.

RESULTS

Statistically, there was a significant difference in the mean maternal blood pressure and heart rate between the left lateral and semi-fowler's positions at 0 and 20 min (P = 0.001), whereas within the groups, in the same position at 0 and 20 min, no significant difference was found. There was no significant difference in NST reactivity (P = 0.79) in different positions. There was no significant difference between the MCR scores of women in either of the positions (Z = -1.64, df = 49, P = 0.100).

CONCLUSION

Semi-fowler's position demonstrated favorable maternal blood pressure and heart rate during the NST in the third trimester of pregnancy, though it was clinically not significant. There was no significant difference in the comfort of women in both positions. Hence, either of the positions can be implemented in practice as an alternative position while performing the NST, based on the women's preference.

Influence of the prone position on a stretcher for pregnant women on maternal and fetal hemodynamic parameters and comfort in pregnancy

OBJECTIVES:

To analyze the influence of lying in prone position on a specially designed stretcher on the maternal-fetal hemodynamic parameters and comfort of pregnant women.

METHODS:

A randomized, controlled trial with 33 pregnant women divided into 2 groups: pregnant group sequence 1 and pregnant group sequence 2. The order of positions used in sequence 1 was Fowler's position, prone position, supine position, left lateral, Fowler's position 2, supine position 2, prone position 2 and left lateral 2. The order of positions used in sequence 2 was Fowler's position, prone position, left lateral, supine position, Fowler's position 2, left lateral 2, prone position 2 and supine position 2. Each woman remained in each position for 6 minutes. For the statistical analyses, we used Wilcoxon's test for 2 paired samples when comparing the prone position with the other positions. The variables are presented in graphs showing the means and 95% confidence intervals. Trial Registration: Clinical Trial No. ISRCTN41359519.

RESULTS:

All the parameters were within the standards of normality. There were no differences between positions in terms of maternal heart rate, diastolic blood pressure, oxygen saturation and fetal heart rate. However, there were significant decreases in respiratory rate and systolic blood pressure in prone position 2 compared with left lateral 2. There was an increase in oxygen saturation in prone position compared with Fowler's position and supine position 2 in both sequences. All the women reported feeling comfortable in the prone position.

CONCLUSIONS:

The prone position was considered safe and comfortable and could be advantageous for improving oxygen saturation and reducing the systolic blood pressure and respiratory rate.

Factors that increase reactivity during fetal nonstress testing

PURPOSE OF REVIEW

The most common method of antepartum fetal surveillance is the nonstress test (NST). Although it has satisfactory false-negative rates, dubious nonreactive results may challenge the physician. Any method or factor increasing the reactive NST results or shortening the time to attain a reactive test may be considerably useful.

RECENT FINDINGS

Most of the studies have found no effect of maternal glucose administration on fetal heart rate and fetal activity, specificity of NST, time to reactivity and percentage of reactive NST results when compared with the control group. Maternal intake of 70% cocoa or caffeine had stimulating action on the fetal reactivity, and this effect on the fetal heart rate was more marked with high concentrations of cocoa (80%). Studies on maternal positioning during NST had equivocal results. Fetal manipulation has no impact on the NST reactivity. Vibroacoustic and halogen light stimulation may be associated with a reduction in time to reactivity.

SUMMARY

These methods may increase the reactivity during a NST and may facilitate the antenatal fetal surveillance.

Effect of uterine contraction and amniotomy on fetal cardiotocograph

Both uterine contractions and artificial rupture of fetal membranes (amniotomy) are important events during delivery phase, this study was planned to determine possible effects of both events on fetal heart rate using nonstress test method. Sixty term pregnant women admitted for termination of pregnancy were selected. Primary nonstress test was performed, then nonstress test was done after active uterine contractions. After the amniotomy the last test was done. All results were statistically analyzed. Out of 60 term pregnant women, 51 (85%) patients reported acceleration for primary nonstress test. After uterine contractions, acceleration was seen in 46 (76.7%) patients, this happened in 40 (66.7%) cases after amniotomy. There was no deceleration after primary nonstress test. However, deceleration reported after uterine contractions and amniotomy in five (8.3%) and two (3.3%) cases, respectively. The 56 (93.3%) patients showed variability in primary nonstress test; variability following the uterine contractions and amniotomy was seen in 58 (96.7%) and 56 (93.3%) of subjects, respectively. None of them were statistically significant (p > 0.05). Mean fetal heart rate baseline in primary Nonstress test was (141.00 +/- 9.35), this was (140.50 +/-10.51) following uterine contractions and (143.08 +/- 11.97) after amniotomy. Baseline fetal heart rate reduction, statistically significant, was seen following uterine contractions (r = +0.28, p = 0.02). This means reductions in lower baseline fetal heart rates will be more outstanding. Uterine contractions and amniotomy had no correlation with presence or absence of variability, acceleration and deceleration.