Borderline or marginal amniotic fluid index and peripartum outcomes: a review of the literature

Comparison of Perinatal and Maternal Outcomes in Borderline Versus Normal Amniotic Fluid Index in a Tertiary Care Center in Odisha: An Observational Prospective Study

Background

Amniotic fluid is a protective fluid in the amniotic sac of a gravid uterus that serves many crucial functions by becoming part of an indicator of a functioning fetoplacental unit during the intrauterine life of a fetus. The most commonly used method for measuring amniotic fluid is the amniotic fluid index (AFI). In this study, we aimed to investigate the perinatal and maternal outcomes in borderline AFI versus normal AFI.

Methodology

This observational prospective study included 200 pregnant women who were admitted to Pradyumna Bal Memorial Hospital, Bhubaneswar from September 2019 to February 2021. Women with singleton pregnancy in their third trimester were enrolled in this study after applying inclusion and exclusion criteria. Of the included women, 100 were cases with borderline AFI, and 100 were control with normal AFI. Fetal and maternal outcomes were compared between the two groups. Data analysis was done using SPSS version 23 (IBM Corp., Armonk, NY, USA).

Results

Maternal outcomes such as preterm delivery, meconium-stained liquor, and lower segment cesarean section in women with borderline AFI were significantly higher (p ≤ 0.001). The borderline AFI group had a higher rate of perinatal complications such as Apgar score of <7 (p = 0.001), respiratory distress syndrome (p = 0.001), neonatal intensive care unit admission (p <0.001), intrauterine growth restriction (p < 0.001), and low birth weight (p < 0.001).

Conclusions

The borderline AFI group was associated with adverse perinatal and maternal outcomes which were significantly higher in this group compared to the control group. Therefore, patients with borderline AFI should be monitored carefully during the antepartum and intrapartum period.

Correlation of amniotic fluid index and placental aquaporin 1 levels in terms of preeclampsia

INTRODUCTION

Aquaporin 1 (AQP1) plays an important role in regulation of maternal-fetal fluid exchange and amniotic fluid volume. This present study aimed to determine the relationship between amniotic fluid index and placental AQP1 levels in terms of preeclampsia, and to reveal possible pathophysiological changes of AQP1 expression under preeclamptic conditions.

METHODS

Placental tissues and medical records information were obtained from 389 preeclamptic and 447 uncomplicated pregnancies. Placental AQP1 levels were analyzed by molecular biological methods, DNA methylation within gene promotor was determined by targeted bisulfite sequencing assay.

RESULTS

Here, we found that preeclamptic pregnancy had a greater frequency of oligohydramnios, and higher placental AQP1 levels. There was a significantly inverse correlation between amniotic fluid index and placental AQP1 levels in preeclampsia cases. Additionally, the increased AQP1 was correlated with a decreased DNA methylation within its gene promoter.

DISCUSSION

Overall, this was the first description that a greater frequency of oligohydramnios in preeclampsia was strongly associated with reprogrammed AQP1 expression via a DNA methylation-mediated epigenetic mechanism. This study suggested AQP1 might play an important role in regulating maternal-fetal fluid balance under preeclamptic conditions, providing new information for further understanding the pathophysiological mechanism of oligohydramnios in preeclampsia.

Association between antenatal ultrasound findings and neonatal outcomes in rural Uganda: a secondary analysis

BACKGROUND

Although the use of prenatal ultrasound services has increased in low- income and lower middle-income countries, there has not been a concurrent improvement in perinatal mortality. It remains unknown whether individual ultrasound findings in this setting are associated with neonatal death or the need for resuscitation at delivery. If associations are identified by ultrasound, they could be used to inform the birth attendant and counsel the family regarding risk, potentially altering delivery preparedness in order to reduce neonatal mortality.

METHODS

This was a secondary analysis of data collected from a prospective cohort. Data was gathered at Nawanyago Health Centre III in Kamuli District, Uganda. Participants included pregnant women who received second and third trimester prenatal ultrasound scans and delivered at that center between July 2010 and August 2018. All ultrasounds were performed at Nawanyago and deliveries were attended solely by midwives or nurses. Predictor variables included the following ultrasound findings: fetal number, fetal presentation, and amniotic fluid volume. The primary outcome was bag-mask ventilation (BMV) of the neonate at delivery. The secondary outcome was stillbirth or neonatal death in the delivery room.

RESULTS

Primary outcome data was available for 1105 infants and secondary outcome data was available for 1098 infants. A total of 33 infants received BMV at delivery. The odds of receiving BMV at delivery was significantly increased if amniotic fluid volume was abnormal (OR 4.2, CI 1.2-14.9) and there were increased odds for multiple gestation (OR 1.9, CI 0.7-5.4) and for non-vertex fetal presentation (OR 1.4, CI 0.6-3.2) that were not statistically significant. Stillbirth or neonatal death in the delivery room was diagnosed for 20 infants. Multiple gestation (OR 4.7, CI 1.6-14.2) and abnormal amniotic fluid volume (OR 4.8, CI 1.0-22.1) increased the odds of stillbirth or neonatal death in the delivery room, though only multiple gestation was statistically significant.

CONCLUSION

Common findings that are easily identifiable on ultrasound in low- and lower middle-income countries are associated with adverse perinatal outcomes. Education could lead to improved delivery preparedness, with the potential to reduce perinatal mortality. This was a preliminary study; larger prospective studies are needed to confirm these findings.

Does the Summer Season Affect the Amniotic Fluid Volume during Pregnancy?

Amniotic fluid is crucial for the well-being of the fetus. Recent studies suggest that dehydration in a pregnant woman leads to oligohydramnios. We assessed the variation in the amniotic fluid index (AFI) during the summer and non-summer seasons and evaluated neonatal outcomes. We retrospectively reviewed electrical medical records of pregnant women who visited the Konkuk University Medical Center for antenatal care, between July 2005 and July 2019. A total of 19,724 cases from 6438 singleton pregnant women were included after excluding unsuitable cases. All AFI values were classified as 2nd and 3rd trimester values. Additionally, borderline oligohydramnios (AFI, 5–8) and normal AFI (AFI, 8–24) were assessed according to the seasons. The average AFI between the summer and non-summer season was statistically different only in the 3rd trimester; but the results were not clinically significant. In the 3rd trimester, the summer season influenced the increased incidence of borderline oligohydramnios. The borderline oligohydramnios group showed an increased small-for-gestational-age (SGA) rate and NICU admission rate. In the summer season, the incidence of borderline oligohydramnios was seen to increase. This result would be significant for both physicians and pregnant women.

Amnioinfusion in severe oligohydramnios with intact membrane: an observational study

OBJECTIVE

The objective of this article was to evaluate the outcome of transabdominal amnioinfusion in pregnant patients with oligohydramnios.

METHOD

This is a prospective observational study involving 80 cases of oligohydramnios treated with transabdominal amnioinfusion guided by ultrasound, in the period between 2011 and 2016. The patients were treated in two centers; however, all the procedures were performed by the same operator.

RESULTS

The mean gestational age at the first treatment was 24 weeks. Some patients received more than one amnioinfusion. The mean interval between the first infusion and delivery was 31 d. Perinatal and neonatal mortalities were 45% and 35%, respectively. There were five cases of chorioamnioitis and in majority of the cases; the final diagnosis was made after amnioinfusion.

CONCLUSION

The procedure has been proven to be very safe. The result showed a high perinatal mortality which was not surprising, as these pregnancies were complicated by a major fetal malformation. Significantly, this study showed that the diagnosis accuracy of the concomitant congenital fetal malformation was significantly improved. The diagnosis accuracy had a major impact on the management of patients, especially the mode of delivery.

Effect of coffee consumption on fetal renal artery blood flow and amniotic fluid volume in third trimester of pregnancy

Objective:

Coffee is frequently (one or two cups/day) consumed throughout pregnancy. Although there are a few studies evaluating caffeine effects on pregnancy; however, a diuretic effect of caffeine on fetal kidneys has not been reported. Therefore, after drinking coffee whether changing of amniotic fluid index (AFI) and fetal renal artery blood flow (FRABF, RI, Resistive index; PI, Pulsatility index) were evaluated in this study.

Methods:

This clinical study was performed with two groups. For the study group, 63 participants with isolated borderline oligohydramnios who agreed to drink one cup of instant coffee were included in this study while 63 participants with isolated borderline oligohydramnios who did not drink one cup of instant coffee formed the control group. AFI, RI and PI were evaluated both before and after coffee intake.

Results:

Maternal characteristics of all study population were homogenous. FRABF indices were similar in both before and after coffee consumption. AFI was increased significantly six hours after drinking coffee (p<0.001).

Conclusions:

The coffee consumption increased the amniotic fluid volume. However it does not seem to affect on FRABF. According to our study findings, coffee consumption may offer a new opportunity to improve amniotic fluid volume for pregnant women with oligohydramnios.

Sonographic Estimation of Amniotic Fluid Volume Using the Amniotic Fluid Index and the Single Deepest Pocket in a Resource-Limited Setting

Objective

To determine the normal value of amniotic fluid (AF) volume among pregnant women in a Northern Nigerian population and to determine if there is a relationship between AF index (AFI) and single deepest pocket (SDP) with anthropometric variables.

Materials and Methods

A prospective cross-sectional study was conducted among singleton pregnant women at late second and third trimester attending the antenatal clinic in Abubakar Tafawa Balewa Teaching Hospital, Bauchi, from December 2016 to April 2017. The mean AFI and SDP were measured by sonography. Ethical approval was obtained from the institution and informed consent was sought for from all the participants. Descriptive statistics, i.e. mean, standard deviation, and correlation coefficient, were used for the analysis.

Results

A total of 206 women, aged between 18 and 40 years, with fetal gestational ages between 22 and 39 weeks were included in the study. The values for AFI in the study ranged from 12 to 28.7 cm, with a mean value of 19.84 ± 3.64 cm, and SDP ranged from 3.7 to 9.1 cm with a mean value of 6.04 ± 1.12 cm. This study found a weak relationship between the anthropometric variables and AFI and SDP and a strong relationship between AFI and SDP with a correlation coefficient of R = 0.901 and P = 0.014.

Conclusion

This study found the mean values for AF volume using AFI and SDP in the studied population to be 19.84 ± 3.64 cm and 6.04 ± 1.12 cm, respectively; a strong positive relationship between AFI and SDP; and a negative relationship between body mass index with AFI and SDP.

Perinatal outcomes following labor induction with dinoprostone in pregnancies with borderline amniotic fluid index at term: A clinical observation study

AIM

To compare perinatal outcomes of dinoprostone for induced labor in pregnancies with a borderline versus normal amniotic fluid index (AFI) at term, and to investigate the related factors affecting outcomes of cesarean section.

METHODS

The retrospective study was carried out in Hubei Maternal and Child Health Hospital with singleton pregnancies of 37-42 weeks' gestation from January to August 2016. A total of 992 subjects were divided into two groups: borderline AFI group (n =125) with 5 < AFI ≤ 8 and normal AFI group (n = 867) with 8 < AFI ≤ 24.

RESULTS

Time to delivery (P =0.004) and use of oxytocin augmentation (P = 0.011) were significantly lower in pregnancies with borderline AFI. There were no significant differences between the two groups in terms of delivery mode, time to onset of labor, fetal distress, Apgar scores, meconium-stained amniotic fluid, birth weight, or incidences of admission to neonatal intensive care unit (NICU). Gestational hypertension and birth weight were the major factors affecting outcomes of cesarean section in the borderline group (odds ratio [OR] = 13.61, 95% confidence interval [CI] 1.96-94.49, P =0.008 and OR = 1.003, 95% CI 1.001-1.005, P =0.001, respectively). Maternal age (OR = 1.12, 95% CI 1.06-1.19, P < 0.001), parity (OR = 7.57, 95% CI 3.05-18.76, P < 0.001), biparietal diameter (OR = 0.55, 95% CI 0.33-0.91, P = 0.021), and meconium-stained amniotic fluid (OR = 1.56, 95% CI 1.12-2.17, P = 0.009) were related factors in the normal group.

CONCLUSION

The perinatal outcomes of dinoprostone for induced labor are comparable between the two groups. Gestational hypertension and birth weight are factors related to outcomes of cesarean section in the borderline group.

Evaluation of Maternal and Perinatal Outcomes of Induction in Borderline Oligohydramnios at Term

Introduction

Oligohydramnios is described as decreased amniotic fluid volume relative to gestational age. Semiquantitatively it is described using the Amniotic Fluid Index (AFI) which is calculated by adding the depth in centimetres of the largest vertical pocket in each of four equal uterine quadrants. AFI less than or equal to 5 cm is defined as oligohydramnios. A Borderline Oligohydramnios (BO) is defined as AFI 5.1-8 cm.

Aim

To assess the maternal and perinatal outcome of induction in borderline oligohydramnios cases at term.

Materials and Methods

This is a retrospective observational study done from December 2015 to November 2016 in Mahatma Gandhi Medical College and Research Institute, Puducherry, India. Fifty cases of BO with AFI 5.1 cm - 8 cm taken as case and another 50 cases of Normal Liquor (NL) with AFI 8.1 cm - 18 cm taken as control. Data was collected and analysed by SPSS software version 20.0 For qualitative data, the χ²-test or Fisher's-exact test were used and for continuous variables, the t-test was used.

Results

Cases and controls were matched in baseline parameters. More number of cases were found with meconium stained liquor during labour which is statistically significant (p<0.05). Otherwise there were no statistical significant difference between cases and controls in maternal and perinatal outcome.

Conclusion

Induction of labour in cases with BO cases compared to those with NL at term did not show very statistically significant difference in terms of induction to delivery interval and neonatal outcome.

Perinatal outcomes in uncomplicated late preterm pregnancies with borderline oligohydramnios

PURPOSE

The purpose of this study is to determine the adverse perinatal outcomes in uncomplicated late preterm pregnancies with borderline oligohydramnios.

METHODS

A total of 430 pregnant women with an uncomplicated singleton pregnancy at a gestational age of 34 + 0-36 + 6 weeks were included. Borderline oligohydramnios was defined as an amniotic fluid index (AFI) of 5.1-8 cm, which was measured using the four-quadrant technique. Adverse perinatal outcomes were compared between the borderline and normal AFI groups.

RESULTS

Approximately 107 of the 430 pregnant women were borderline AFI, and 323 were normal AFI. The demographic and obstetric characteristics were similar in both groups. Delivery <37 weeks, cesarean delivery for non-reassuring fetal heart-rate testing, meconium-stained amniotic fluid, Apgar 5 min <7, transient tachypnea of the newborn, respiratory distress syndrome, neonatal intensive care unit, and hyperbilirubinemia were not statistically different between the groups (p = .054, p = .134, p = .749, p = 0.858, p = .703, p = .320, p = .185, and p = .996, respectively). Although gestational age was full-term, induction of labor rates were significantly higher in the borderline AFI group (p = .040). In addition, fetal renal artery pulsatility index pulsatility index (PI) was significantly lower in the borderline AFI group than in the normal AFI group (p = .014).

CONCLUSION

Our results indicated that borderline AFI was not a risk for adverse perinatal outcomes in uncomplicated, late preterm pregnancies.

Borderline amniotic fluid index and perinatal outcomes in the uncomplicated term pregnancy

OBJECTIVE

To determine perinatal outcomes in uncomplicated term pregnancies with a borderline amniotic fluid index (AFI).

METHODS

A retrospective review was conducted of uncomplicated singleton pregnancies at term (>37 weeks). Borderline and normal AFI were defined as 5.1 ≤ AFI ≤ 8.0 cm and 8.1 ≤ AFI ≤ 24 cm, respectively. Adverse perinatal outcomes, cesarean delivery for non-reassuring fetal heart rate testing, meconium-stained amniotic fluid, a 5-min Apgar score of <7, admission to the neonatal intensive care unit (NICU), and whether the neonate was small for gestational age were compared between the borderline and normal AFI groups.

RESULTS

Borderline AFI was not significantly associated with cesarean delivery for non-reassuring fetal heart rate testing (p = 0.513), meconium-stained amniotic fluid (p = 0.641), admission to the NICU (p = 0.368), or a 5-min Apgar score of <7 (p = 1.00). However, the number of neonates who were small for gestational age (p = 0.021) and rates of induction of labor (p < 0.001) were significantly higher in the borderline group. Multiple logistic regression analysis showed that borderline AFI was not associated with cesarean delivery for non-reassuring fetal heart rate testing (odds ratio [OR] = 0.72, 95% confidence interval [CI] 0.27-1.91, p = 0.52).

CONCLUSION

In uncomplicated term pregnancies, a borderline AFI does not increase the risk of adverse perinatal outcomes.

Borderline amniotic fluid index and its relation to fetal intolerance of labor: a 2-center retrospective cohort study

OBJECTIVES

To determine whether a borderline amniotic fluid index (AFI) in the third trimester is associated with an increased rate of cesarean delivery for fetal intolerance of labor, meconium-stained amniotic fluid, and intrauterine growth restriction, among other adverse perinatal outcomes.

METHODS

Patients with a diagnosis of a borderline AFI between January 2008 and August 2012 were identified. Antepartum, delivery, and neonatal data were collected and compared to a cohort with a normal AFI.

RESULTS

We enrolled 739 patients, including 177 with a borderline AFI (>5 and <10 cm) and 562 with a normal AFI (≥ 10-24 cm); 360 patients delivered at University of Arizona Medical Center, and 379 delivered at St Joseph's Hospital. Combined and individual analyses of each center revealed no significant difference in fetal intolerance of labor (P = .19) or cesarean delivery for fetal intolerance (P = .074) between cohorts. In both settings, patients with a borderline AFI were more likely than those with a normal AFI to undergo antepartum testing (P < .001). A statistically significant increase in intrauterine growth restriction in the borderline AFI group was noted, with a calculated risk ratio of 13.76 (P < .001). There was no difference between groups for meconium-stained amniotic fluid (P = .23), neonatal intensive care unit admission (P = .054), preterm delivery (P = .31), or operative vaginal delivery (P = .45).

CONCLUSIONS

The findings of this study suggest that there is no difference in the rate of fetal intolerance of labor in pregnancies with a borderline AFI and those with a normal AFI. Pregnancies complicated by a borderline AFI are more likely to undergo antepartum testing, yet the benefit is unclear. Significantly more patients with a borderline AFI had underlying growth restriction, which may provide a useful tool for risk stratification in the management of a borderline AFI.

Toward consistent terminology: assessment and reporting of amniotic fluid volume

Amniotic fluid is typically measured by ultrasound using the amniotic fluid index (AFI) or the maximum vertical pocket (MVP). Although both parameters correlate poorly with the actual amniotic fluid volume measured with dye-dilution methods, cross-sectional studies have been used to establish gestational norms. The current acceptable definition of polyhydramnios in the late second and the third trimester in both singleton and multiple gestations is a MVP > 8 cm, while the definition of oligohydramnios is a MVP < 2 cm. The pocket to be measured should exclude the umbilical cord or fetal parts. Randomized clinical trials have indicated that defining oligohydramnios as a MVP < 2 cm will result in fewer obstetrical interventions and similar perinatal outcomes when compared to an AFI < 5 cm.

Amniotic fluid as a vital sign for fetal wellbeing

Introduction: Amniotic fluid, once thought to merely provide protection and room for necessary movement and growth for the fetus, is now understood to be a highly complex and dynamic system that is studied as a data point to interpret fetal wellbeing. Methods: Assessment of amniotic fluid volume is now routine when performing a sonographic evaluation of fetal status and is an important consideration in the assessment and management of perinatal morbidity and mortality.1,2 In this review, we will cover the dynamics that affect amniotic fluid volume, review methods for measurement and quantification of volume, review definitions for normative data as related to neonatal outcomes, and provide evidence based guidance on the workup and management options for oligoydramnios and polyhydramnios in singleton and twin pregnancies. Conclusions: When abnormalities of fluid exist, appropriate workup to uncover the underlying etiology should be initiated as adverse fetal outcomes are sometimes associated with these variations from normalcy.