The Effect of Maternal Lower Limb Compression on Amniotic Fluid Index, Uteroplacental Perfusion, and Fetal Blood Flow in Isolated Oligohydramnios

INTRODUCTION

The aim of this study was to examine the efficacy of pneumatic compression of the maternal lower extremities in increasing the amniotic fluid index (AFI) in pregnancies complicated by isolated oligohydramnios.

METHODS

Women with isolated oligohydramnios (AFI <5 cm) at 32-41 weeks of pregnancy were connected to a sequential compression device for 60 min. Prior and after the application, AFI and the pulsatility index (PI) of a number of arteries were measured.

RESULTS

The median (interquartile range) maternal age of the 21 women included was 29 years (26.50-32.00), the median parity was 1 (1-2), and the median gestational age at intervention was 37.60 weeks (37.00-39.40). The median AFI increased after the application from 4.00 (3.62-4.50) to 6.08 cm (4.90-7.03) (p < 0.001). The median PI of the fetal renal artery decreased from 2.30 (2.01-2.88) to 2.26 (1.68-2.71) (p = 0.01). The hourly fetal urine production did not increase. Changes were not significant in the PI of the umbilical artery, the middle cerebral artery, and the bilateral uterine arteries.

CONCLUSION

Short-term activation of pneumatic compression on maternal lower extremities could increase the AFI in women with isolated oligohydramnios.

Amniotic fluid volume at presentation with early preterm prelabor rupture of membranes and association with severe neonatal respiratory morbidity

OBJECTIVE

Amniotic fluid volume (AFV) plays an important role in early fetal lung development, and oligohydramnios in early pregnancy is associated with pulmonary hypoplasia. The aim of this study was to evaluate the association between AFV at the time of presentation with early preterm prelabor rupture of membranes (PPROM) and severe neonatal respiratory morbidity and other adverse pregnancy outcomes.

METHODS

This was a retrospective study of all women with a singleton pregnancy, admitted to a single tertiary referral center between 2004 and 2014, for expectant management of PPROM at 20 + 0 to 28 + 6 weeks' gestation. The primary exposure was AFV at presentation, classified according to sonographic maximum vertical pocket (MVP) as: normal AFV (> 2 cm), oligohydramnios (≤ 2 cm and > 1 cm) or severe oligohydramnios (≤ 1 cm). The primary outcome was a composite variable of severe respiratory morbidity, defined as either of the following: (1) need for respiratory support in the form of mechanical ventilation using an endotracheal tube for ≥ 72 h and need for surfactant; or (2) bronchopulmonary dysplasia, defined as requirement for oxygen at postmenstrual age of 36 weeks or at the time of transfer to a Level-II facility. Adjusted odds ratios (aOR) and 95% CI for the primary and secondary outcomes were calculated for each AFV-at-presentation group (using normal AFV as the reference), adjusting for gestational age (GA) at PPROM, latency period, birth weight, mode of delivery and chorioamnionitis.

RESULTS

In total, 580 women were included, of whom 304 (52.4%) had normal AFV, 161 (27.8%) had oligohydramnios and 115 (19.8%) had severe oligohydramnios at presentation. The rates of severe respiratory morbidity were 16.1%, 26.7% and 45.2%, respectively. Compared with normal AFV at presentation, oligohydramnios (aOR, 3.27; 95% CI, 1.84-5.84) and severe oligohydramnios (aOR, 4.11; 95% CI, 2.26-7.56) at presentation were associated independently with severe respiratory morbidity. Other variables that were associated independently with the primary outcome were GA at PPROM (aOR, 0.54; 95% CI, 0.43-0.69), latency period (aOR, 0.94; 95% CI, 0.91-0.98) and Cesarean delivery (aOR, 2.01; 95% CI, 1.21-3.32).

CONCLUSIONS

In women with early PPROM, AFV at presentation, as assessed by the MVP on ultrasound examination, is associated independently with severe neonatal respiratory morbidity. This information may be taken into consideration when counseling women with early PPROM regarding neonatal outcome and management options. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Effect of intra-amniotic fluid pressure from polyhydramnios on cervical length in patients with twin-twin transfusion syndrome undergoing fetoscopic laser surgery

OBJECTIVES

To determine the relationship between intra-amniotic pressure and cervical length (CL) in patients with twin-twin transfusion syndrome (TTTS) undergoing fetoscopic laser photocoagulation (FLP), and to identify pre- or intraoperative factors associated with increased intra-amniotic pressure in this population.

METHODS

This was a prospective cohort study of patients undergoing FLP for TTTS. Exclusion criteria were triplet or higher-order gestation and prior cervical cerclage, amnioreduction or FLP procedure. CL was assessed using preprocedure transvaginal ultrasound. Intra-amniotic pressure measurements were obtained on initial placement of the trocar into the amniotic cavity, using a direct hydrostatic pressure gauge. The relationship between intra-amniotic pressure and CL was assessed using multivariate linear regression analysis, including relevant preoperative and intraoperative variables.

RESULTS

In total, 283 pregnancies met the inclusion criteria. Quintero stage of TTTS was I in 33 pregnancies, II in 88, III in 150 and IV in 12. Mean gestational age (GA) at FLP was 20.7 ± 3 weeks. Mean intra-amniotic pressure was 23.1 ± 9 mmHg. On unadjusted linear regression analysis, there was no significant association between intra-amniotic pressure and preoperative CL (P = 0.24) or GA at delivery (P = 0.22). On multivariate analysis, the factors associated significantly with intra-amniotic pressure were: number of prior term deliveries (P = 0.03), recipient maximum vertical pocket (P < 0.0001), Quintero stage IV (P = 0.01) and type of anesthesia (sedation vs general anesthesia; P = 0.01).

CONCLUSION

In pregnancies with TTTS, intra-amniotic pressure is not associated with CL or GA at delivery. This novel finding suggests that cervical shortening in this population is not mechanically driven. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The effects of Ramadan fasting during pregnancy on fetal development: a general review

BACKGROUND

From a religious point of view, Ramadan fasting (RF) is not mandatory during pregnancy. However, some pregnant women insist to fast. Does this choice affect fetal development?

AIM

The objective of this general review was to determine the impact of RF on fetal development.

METHODS

The search was conducted via the following databases PubMed, Scopus, Web of Sciences and Google Scholar from January 1st 2009 to December 31th 2018, using the following query: (« Ramadan « OR « Ramadan month « OR « fasting «) AND (« fetal development « OR « fetal growth « OR « fetal programming «) AND (pregnanc* OR gestat* OR pregnant wom*n). Articles published in English or French were included, and comparative studies on the impact of RF on fetal development in the group of pregnant women who fasted and the group who did not fast, regardless of the stage of gestation.

RESULTS

Ten studies met the research criteria and all were case-control ones. Six studies were conducted in Turkey, two in Egypt, one in Iran and one in Pakistan. The RF coincided with the summer period in 8 studies. An obstetrical ultrasound with Doppler was performed on 1390 pregnant women at the beginning and end of Ramadan. Significant decreases in cephalic perimeter, biparietal diameter and femoral length were noted in a single study. A change in the amniotic fluid index was observed in two studies.

CONCLUSION

The RF practiced by healthy pregnant women has no negative impact on fetal development.

Survivability of rabbit amniotic fluid-derived mesenchymal stem cells post slow-freezing or vitrification

This work aimed to evaluate the effect of two distinct cryopreservation procedures - conventional slow-freezing and vitrification, on survivability and mesenchymal marker expression stability of rabbit amniotic fluid-derived mesenchymal stem cells (rAF-MSCs). Cells at passage 2 were slowly frozen, using 10% of dimethylsulfoxide, or vitrified, using 40% of ethylene glycol, 0.5 M sucrose and 18% Ficoll 70. After three months storage in liquid nitrogen, viability, chromosomal stability, ultrastructure, surface and intracellular marker expression and differentiation potential of cells were evaluated immediately post-thawing/warming and after additional culture for 48-72 h. Our results showed decreased (P ≤ 0.05) viability of cells post-thawing/warming. However, after additional culture, the viability was similar to those in fresh counterparts in both cryopreserved groups. Increase (P ≤ 0.05) in the population doubling time of vitrified cells was observed, while doubling time of slow-frozen cells remained similar to non-cryopreserved cells. No changes in karyotype (chromosomal numbers) were observed in frozen/vitrified AF-MSCs, and histological staining confirmed similar differentiation potential of fresh and frozen/vitrified cells. Analysis of mesenchymal marker expression by qPCR showed that both cryopreservation approaches significantly affected expression of CD73 and CD90 surface markers. These changes were not detected using flow cytometry. In summary, the conventional slow-freezing and vitrification are reliable and effective approaches for the cryopreservation of rabbit AF-MSCs. Nevertheless, our study confirmed affected expression of some mesenchymal markers following cryopreservation.

Unexpected finding of uniparental disomy mosaicism in term placentas: Is it a common feature in trisomic placentas?

Objective

Non‐invasive prenatal testing (NIPT) detects placental chromosome aberrations. When amniocentesis reveals a normal karyotype, confined placental mosaicism (CPM) may be assumed. In order to confirm this, placental cytogenetic studies were performed.

Method

NIPT was conducted in the course of the Dutch TRIDENT study. Placentas of 10 cases with NIPT results indicating an autosomal trisomy and showing a normal (N = 9) or low mosaic karyotype (N = 1) in amniotic fluid (AF) were investigated. The cytotrophoblast as well as the mesenchymal core of two to four placental chorionic villi biopsies were studied with single nucleotide polymorphism (SNP) array. Clinical outcome data were collected.

Results

In 10/10 cases, CPM was proven. In 3/10 cases trisomy/uniparental disomy (UPD)/biparental disomy (BPD) mosaicism was discovered. In 2/3 cases, all three cell lines were present in the placenta, whereas BPD was found in AF. In 1/3 cases trisomy 22/UPD22 was present in AF while trisomy 22/BPD22 mosaicism was found in the placenta. Five of 10 pregnancies were affected with pre‐eclampsia, low birth weight, preterm delivery, and/or congenital malformations.

Conclusion

The presence of trisomy/UPD/BPD mosaicism in 3/10 cases that we investigated proves that trisomic zygote rescue may involve multiple rescue events during early embryogenesis. UPD mosaicism, when present in crucial fetal tissues, may explain the abnormal phenotype in undiagnosed cases.

What's already known about this topic?

Trisomic zygote rescue is the main mechanism for uniparental disomy (UPD) formation.

Confined placental mosaicism (CPM) is the major source of discordant NIPT results.

CPM is associated with a risk for adverse pregnancy outcome.

What does this study add?

Trisomic zygote rescue may involve multiple rescue events based on the co‐occurrence of a trisomy‐, UPD‐, and BPD‐cell line in half of the rescued cases as revealed by placental studies.

Selected physicochemical properties of amniotic fluid according to week of pregnancy

BACKGROUND

A hundred years ago, scientists believed that amniotic fluid is a yellowish hypotonic mixture of foetal urine and maternal transudate with peculiar odour. Current knowledge shows that it represents a dynamic, complex mixture of inorganic and organic compounds.

OBJECTIVES

Despite modern technological procedures, information is still lacking about the composition and properties of amniotic fluid. We focused on dynamics of selected physical and chemical properties of the amniotic fluid with the increasing gestational week.

METHODS

The physicochemical characteristics of 89 amniotic fluid samples were determined according to the week of pregnancy. The determination of pH, specific gravity, glucose and nitrites was performed immediately, at room temperature.

RESULTS

Our results show a significant negative correlation between week of pregnancy and semi-quantitative determined parameters of specific gravity (p < 0.001), pH (p < 0.01) and glucose (p < 0.001) values. Within the whole group of samples (n = 89), 29 % (n = 26) were nitrites positive (N+) and 71 % (n = 63) nitrites negative (N-).

CONCLUSION

In this study were determined basic parameters of amniotic fluid, which could be related to a wide range of pathological states (Tab. 2, Fig. 1, Ref. 27).

Early Taste Experiences and Later Food Choices

Background. Nutrition in early life is increasingly considered to be an important factor influencing later health. Food preferences are formed in infancy, are tracked into childhood and beyond, and complementary feeding practices are crucial to prevent obesity later in life. Methods. Through a literature search strategy, we have investigated the role of breastfeeding, of complementary feeding, and the parental and sociocultural factors which contribute to set food preferences early in life. Results. Children are predisposed to prefer high-energy, -sugar, and -salt foods, and in pre-school age to reject new foods (food neophobia). While genetically determined individual differences exist, repeated offering of foods can modify innate preferences. Conclusions. Starting in the prenatal period, a varied exposure through amniotic fluid and repeated experiences with novel flavors during breastfeeding and complementary feeding increase children’s willingness to try new foods within a positive social environment.

Reference values for the single deepest vertical pocket to assess the amniotic fluid volume in the second and third trimesters of pregnancy

AIM

To establish reference values for the single deepest vertical pocket to assess the amniotic fluid volume in the second and third trimesters of pregnancy.

METHODS

We performed a retrospective cross-sectional study with 3554 consecutive singleton low-risk pregnant women between 14 and 41 weeks of gestation. To perform the largest deepest vertical pocket measurement, the transabdominal convex probe was positioned vertical to the uterine contour of abdomen and parallel to the maternal sagittal plane. In order to obtain reference values for the largest deepest vertical pocket measurement and gestational age (GA), we have used a polynomial regression model.

RESULTS

The mean±standard deviation for the largest deepest vertical pocket measurement (cm) ranged from 3.1±1.1 (1.5-4.9) at 14-14+6 to 3.7±1.6 (0-6.7) at 41-41+6 weeks, respectively. A best-fit was a second-degree polynomial regression: largest deepest pocket=-1.478+0.197*GA-0.0030*GA2 (R2=0.014).

CONCLUSION

Reference values for the single deepest vertical pocket to assess the amniotic fluid volume in the second and third trimesters of pregnancy in a large heterogeneous population were established.

Fetal Development: Voice Processing in Normotensive and Hypertensive Pregnancies

Recent observation of maternal voice recognition provides evidence of rudimentary memory and learning in healthy term fetuses. However, such higher order auditory processing has not been examined in the presence of maternal hypertension, which is associated with reduced and/or impaired uteroplacental blood flow. In this study, voice processing was examined in 40 fetuses (gestational ages of 33 to 41 weeks) of hypertensive and normotensive women. Fetuses received 2 min of no sound, 2 min of a tape-recorded story read by their mothers or by a female stranger, and 2 min of no sound while fetal heart rate was recorded. Results demonstrated that fetuses in the normotensive group had heart rate accelerations during the playing of their mother's voice, whereas the response occurred in the hypertensive group following maternal voice offset. Across all fetuses, a greater fetal heart rate change was observed when the amniotic fluid index was above compared to below the median (i.e., 150 mm), indicating that amniotic fluid volume may be an independent moderator of fetal auditory sensitivity. It was concluded that differential fetal responding to the mother's voice in pregnancies complicated by maternal hypertension may reflect functional elevation of sensorineural threshold or a delay in auditory system maturation, signifying functional differences during fetal life or subtle differences in the development of the central nervous system.

More than fetal urine: enteral uptake of amniotic fluid as a major predictor for fetal growth during late gestation

The purpose of our study was to investigate the importance of amniotic fluid (AF) for fetal growth during late gestation using esophageal atresia (EA) patients as a model. In this retrospective cohort study, we compared the z-scores adapted for birth weights (BW z-scores) for each of 517 European newborns with congenital pre-gastric intestinal atresia, i.e., EA, to a European reference population. To account for the influence of the intestinal atresia on fetal growth per se, we compared adapted birth weights for each of 504 European newborns with post colonic intestinal atresia (anorectal malformation (ARM) with atresia of the anus) to the same European reference population. Analysis of the complete cohort showed (i) a significantly higher rate of small for gestational age newborns among EA compared to ARM newborns (p < 0.001) and (ii) significantly lower BW z-scores among EA compared to ARM newborns (p < 0.001). BW z-scores of EA newborns were significantly lower in term compared to preterm newborns with an inverse correlation with gestational age (GA) (Spearman correlation coefficient, r = -0.185, p < 0.001).

CONCLUSIONS

Enteral uptake of AF seems to play a pivotal role in fetal growth during late gestation.

WHAT IS KNOWN

• Peak velocity of fetal weight gain occurs at 33 weeks of gestation and continues until birth. During this period, fetal growth is mainly characterized by cellular hypertrophy. • Amniotic fluid (AF) comprises large amounts of hormones and growth regulators. What is New: • A significantly higher rate of small for gestational age and lower birth weights and z-scores are observed among newborn infants with congenital pre-gastric intestinal atresia. • These findings suggest that enteral uptake of AF is a major predictor for fetal growth during late gestation.

In-utero radiofrequency ablation in fetal piglets: Lessons learned

INTRODUCTION

Radiofrequency ablation (RFA) is increasingly utilized in minimally invasive fetal intervention. However, the response of different fetal tissues to RFA is poorly characterized. We sought to determine the extent of RFA damage in a fetal environment.

METHODS

90Day gestation Yorkshire piglets (term 115days) were subjected to RFA of the chest and abdominal viscera under various temperatures and wattages. The extent of tissue damage was determined by NADPH diaphorase histochemistry.

RESULTS

Tyne temperature was widely variable and displayed varying responses between lung and liver tissue. Tyne exposure to amniotic fluid resulted in an increase in amniotic fluid temperature. Collateral damage, even across the diaphragm, was readily seen, and ultrasonography did not always reflect this injury.

CONCLUSIONS

Utilization of extracorporeal tynes heats fluid at a greater rate than solid tissue and reliance on temperature sensitive probes may result in overheating. The extent of injury may extend beyond damage observed by ultrasound examination and varies for different tissues. Additional studies on the use of devices that regulate tyne temperature are needed to define optimal conditions and better define the extent of adjacent tissue injury.

Outcomes of different concentrations of human amniotic fluid in a keratoconjunctivitis sicca-induced mouse model

To compare the effects of different concentrations of topical human amniotic fluid (HAF) in a mouse model of dry eye, forty C57BL/6 mice were divided into 4 treatment groups: 20 % HAF, 50 % HAF, 100 % HAF, and isotonic salt solution (control). Dry eye was induced by an injection of botulinum toxin B into the lacrimal gland. Tear production, ocular surface fluorescein staining, and blink rate were evaluated in each mouse at 5 time points during a 4-week period. Goblet cell density was assessed in stained histological sections. Regarding tear production, 20, 50, and 100 % HAF groups were all different from the control group (P < 0.001) at week 1. However, there were no statistically significant differences between the 20, 50, and 100 % HAF groups. At week 2, 20, 50, and 100 % HAF groups had significant improvement in staining score and were significantly different from the control group (P = 0.047, P = 0.005, and P = 0.001, respectively). No difference in spontaneous blink rate was observed between groups, at any time point. Goblet cell density was significantly decreased in the control group compared to the HAF treatment groups. All tested concentrations of topical HAF were effective and superior than the control in this keratoconjunctivitis sicca-induced mouse model. Further studies are needed to evaluate the effects of HAF on the human ocular surface.

Influence of parity on fetal hemodynamics and amniotic fluid volume at term

OBJECTIVES

Pregnancy complications, particularly those associated with placental dysfunction, occur more frequently in nulliparous than in parous women. This difference may be a consequence of improved trophoblastic invasion and, as a result, improved placental function following previous pregnancy. Placental dysfunction in cases of fetal growth restriction may be identified by ultrasound assessment of fetoplacental hemodynamics and amniotic fluid volume. In this prospective observational study, we investigated whether differences in these measures of placental function exist between nulliparous and parous women, prior to active labor.

METHODS

Over a 2-year period, 456 nulliparous and 152 parous women with uncomplicated singleton pregnancies were recruited to this prospective observational study. Each participant underwent an ultrasound assessment prior to active labor, during which fetal biometry, umbilical artery, middle cerebral artery and umbilical venous Dopplers, as well as amniotic fluid volume, were assessed. All cases were followed up within 48 h of delivery. Ultrasound parameters and intrapartum outcomes were then compared between the nulliparous and parous groups.

RESULTS

Compared with nulliparous women, parous women had significantly higher fetal middle cerebral artery pulsatility index, cerebroplacental ratio and amniotic fluid volume. In nulliparous women, middle cerebral artery flow rate was also significantly higher and represented a greater percentage of umbilical venous flow than was observed in parous women.

CONCLUSION

Prior to the active phase of labor, ultrasound parameters indicative of placental function differ significantly between nulliparous and parous pregnancy, even amongst an uncomplicated, low-risk cohort.

Amnioinfusion for third trimester preterm premature rupture of membranes

BACKGROUND

Preterm premature rupture of membranes (PPROM) is a leading cause of perinatal morbidity and mortality. Amnioinfusion aims to restore amniotic fluid volume by infusing a solution into the uterine cavity.

OBJECTIVES

The objective of this review was to assess the effects of amnioinfusion for PPROM on perinatal and maternal morbidity and mortality.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (2 December 2013).

SELECTION CRITERIA

Randomised trials of amnioinfusion compared with no amnioinfusion in women with PPROM.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion. Two review authors independently assessed trial quality and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included five trials, of moderate quality, but we only analysed data from four studies (with a total of 241 participants). One trial did not contribute any data to the review.Transcervical amnioinfusion improved fetal umbilical artery pH at delivery (mean difference 0.11; 95% confidence interval (CI) 0.08 to 0.14; one trial, 61 participants) and reduced persistent variable decelerations during labour (risk ratio (RR) 0.52; 95% CI 0.30 to 0.91; one trial, 86 participants).Transabdominal amnioinfusion was associated with a reduction in neonatal death (RR 0.30; 95% CI 0.14 to 0.66; two trials, 94 participants), neonatal sepsis (RR 0.26; 95% CI 0.11 to 0.61; one trial, 60 participants), pulmonary hypoplasia (RR 0.22; 95% CI 0.06 to 0.88; one trial, 34 participants) and puerperal sepsis (RR 0.20; 95% CI 0.05 to 0.84; one trial, 60 participants). Women in the amnioinfusion group were also less likely to deliver within seven days of membrane rupture (RR 0.18; 95% CI 0.05 to 0.70; one trial, 34 participants). These results should be treated with circumspection as the positive findings were mainly due to one trial with unclear allocation concealment.

AUTHORS' CONCLUSIONS

These results are encouraging but are limited by the sparse data and unclear methodological robustness, therefore further evidence is required before amnioinfusion for PPROM can be recommended for routine clinical practice.

Treatment of PPROM with anhydramnion in humans: first experience with different amniotic fluid substitutes for continuous amnioinfusion through a subcutaneously implanted port system

OBJECTIVE

This study aims to treat patients with preterm premature rupture of the membranes (PPROM) and anhydramnion using continuous amnioinfusion through a subcutaneously implanted port system.

METHODS

An amniotic fluid replacement port system was implanted in seven patients with PPROM and anhydramnion starting at the 20th week of gestation (range, 14-26 weeks) for long-term amnioinfusion. Saline solutions (2 L/day; Jonosteril(®), Sterofundin(®), isotonic NaCl 0.9% solution, lactated Ringer's solution) and a hypotonic aqueous composition with reduced chloride content similar to the electrolyte concentration of human amniotic fluid were used for the continuous amnioinfusion.

RESULTS

The mean duration of the PPROM delivery interval continued for 49 days (range, 9-69 days), with 3 weeks of amnioinfusion via the port system (range, 4-49). The newborns showed no signs of lung hypoplasia.

CONCLUSION

Long-term lavage of the amniotic cavity via a subcutaneously implanted port system in patients with PPROM and anhydramnion may help prolong the pregnancy and avoid fetal lung hypoplasia. A hypotonic aqueous composition with reduced chloride content similar to human amniotic fluid can be safely used for amnioinfusion. Prospective randomized studies are ongoing.

Amniotic fluid may act as a transporting pathway for signaling molecules and stem cells during the embryonic development of amniotes

Amniotic fluid (AF) is formed at the very early stages of pregnancy, and is present throughout embryonic development of amniotes. It is well-known that AF provides a protective sac around the fetus that allows fetal movement and growth, and prevents mechanical and thermal shock. However, a growing body of evidence has shown that AF contains a number of proteins and peptides, including growth factors and cytokines, which potently affect cellular growth and proliferation. In addition, pluripotent stem cells have recently been identified in AF. Herein, this article reviews the biological properties of AF during embryonic development and speculates that AF may act as a transporting pathway for signaling molecules and stem cells during amniote embryonic development. Defining this novel function of AF is potentially significant for further understanding embryonic development and regenerative medicine, preventing genetic diseases, and developing therapeutic options for human malignancies.

Effects of maternal left lateral position and rest on amniotic fluid index: a prospective clinical study

OBJECTIVE

To compare the effect of both maternal rest and activity on the amniotic fluid index (AFI).

STUDY DESIGN

Power analysis indicated that in order to achieve 20 mm of increase in AFI with 90% of power at one side alpha of 0.01, we needed at least 51 women in each group. The study group was comprised of pregnant women (n = 152) with a normal AFI and a singleton pregnancy at 26-40 weeks' gestation. Their AFI was determined by averaging the 2 repetitive measurements of the 4 amniotic fluid quadrants. The "rest" group (n = 77) was instructed to lie and rest in the left lateral position, and the "mild activity" group (n = 75) was instructed to sit and walk.

RESULTS

AFI increased significantly, from 151.25 +/- 37.40 mm to 173.79 +/- 39.76 mm, in the "rest" group (p = 0.00). However, the change from 153.69 +/- 37.94 to 152.34 +/- 36.62 mm was not significant in the "mild activity" group (p = 0.167).

CONCLUSION

Maternal rest in the left lateral position increases the AFI.

Correlation between the duration of maternal rest in the left lateral decubitus position and the amniotic fluid volume increase

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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).