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

Routine third trimester ultrasonography in predicting adverse perinatal outcomes: a prospective cohort study at a tertiary-care hospital in Eastern India

AIMS

Fetal growth restriction (FGR) may go undetected in the antenatal period with subjective clinical evaluation, and there is a growing propensity to perform a third-trimester scan, especially in the developed countries. The literature on the importance of the same in developing countries like ours, is scant. Hence, this study was undertaken to evaluate the role of routine third-trimester ultrasonography along with Doppler in predicting adverse perinatal outcome.

METHODS

A prospective cohort study was conducted at a tertiary-care hospital, in which routine third-trimester ultrasonography was performed for 265 antenatal women, and included estimation of amniotic fluid index (AFI), estimated fetal-weight (EFW), and cerebroplacental ratio (CPR). Women were categorized as having normal parameters or having at least one abnormal parameter. Post-natal adverse perinatal outcomes including low birth-weight, hypoglycemia, poor Apgar scores, prolonged hospital stay, need for ventilatory support, neonatal asphyxia, neonatal sepsis and early neonatal death were recorded. Prediction analyses for sensitivity, specificity, positive and negative predictive values were done. Receiver Operating Characteristic (ROC) curves were plotted for threshold for each parameter for adverse outcome.

RESULTS

Out of 260 women that were analyzed, 47.5% had no clinically identifiable risk factors, and 52.5% had at least one abnormal parameter. Sensitivity and negative predictive value for adverse outcome were highest for composite ultrasound finding (85.4% and 90.4% respectively). Specificity, positive predictive value and diagnostic accuracy were highest for CPR (97.8%, 86.7% and 76.9% respectively).

CONCLUSION

Routine third trimester ultrasonography, including Doppler, can help in risk-stratification of otherwise clinically low-risk pregnancies.

First Trimester Tricuspid Regurgitation: Clinical Significance

Tricuspid regurgitation is a cardiac valvular anomaly that consists of the return of blood to the right atrium during systole due to incomplete valve closure. This structure can be visualized on ultrasound between 11 and 14 weeks of gestation in most cases. Despite being a common finding, even in healthy fetuses, the presence of tricuspid regurgitation may be associated with chromosomal and structural abnormalities. The evaluation of tricuspid flow and the presence of regurgitation on first-trimester ultrasound has shown promising results regarding its role in the early detection of aneuploidies, congenital heart defects, and other adverse perinatal outcomes. This review article aims to demonstrate the importance of tricuspid regurgitation as a secondary marker, and consequently, significant benefits of its early detection when added to the combined first-trimester screening. Its value will be discussed, namely its sensitivity and specificity, alone and together with other current markers in the fetal assessment performed in the first-trimester ultrasound.

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.

Mild Fetal Tricuspid Regurgitation in the First Trimester as a Predictor of Perinatal Outcomes

Background and Objectives: This study aimed to investigate whether mild fetal tricuspid regurgitation (TR) at 11^+ 0 to 13^+ 6 weeks of gestation affects perinatal outcomes. Since fetal right ventricular load is associated with placental resistance, we hypothesized that fetal mild TR would be associated with perinatal outcomes as a consequence of abnormal placentation. Materials and Methods: We retrospectively evaluated 435 women with first-trimester scan data. Blood flow across the tricuspid valve was examined in singleton pregnancies between 11^+ 0 and 13^+ 6 weeks of gestation. Women were categorized according to the presence or absence of fetal mild TR, and the maternal and pregnancy characteristics and perinatal outcomes were compared. Multiple linear and logistic regression analyses were conducted to identify independent predictors of perinatal outcome. Results: In the group with mild TR, there were more cases of borderline amniotic fluid index, including oligohydramnios (p = 0.031), and gestational age- and sex-specific birth weights were lower (p = 0.012). There were no significant differences in other perinatal outcomes, including preeclampsia, gestational hypertension and small for gestational age. Gestational diabetes (adjusted odds ratio (OR) 0.514, 95% confidence interval (CI) 0.312–0.947) and fetal mild TR (adjusted OR 1.602, 95% CI 1.080–2.384) were identified as factors associated with below borderline amniotic fluid index before birth. The factors that affected gestational age and sex-specific birth weight were also gestational diabetes (adjusted beta coefficient 9.673, p = 0.008) and the presence of fetal mild TR (adjusted beta coefficient −6.593, p = 0.007). Conclusions: Mild fetal TR observed in the first trimester is negatively associated with fetal growth and the amniotic fluid index at term but not with other adverse pregnancy or perinatal outcomes due to abnormal placentation.

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.

Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis

BACKGROUND

Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

OBJECTIVES

We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. The main questions addressed were the diagnostic effectiveness of universal late pregnancy ultrasound to predict adverse outcomes and the cost-effectiveness of either implementing universal ultrasound or conducting further research in this area.

DESIGN

We performed diagnostic test accuracy reviews of five ultrasonic measurements in late pregnancy. We conducted cost-effectiveness and value-of-information analyses of screening for fetal presentation, screening for small for gestational age fetuses and screening for large for gestational age fetuses. Finally, we conducted a survey and a focus group to determine the willingness of women to participate in a future randomised controlled trial.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane Library from inception to June 2019.

REVIEW METHODS

The protocol for the review was designed a priori and registered. Eligible studies were identified using keywords, with no restrictions for language or location. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Health economic modelling employed a decision tree analysed via Monte Carlo simulation. Health outcomes were from the fetal perspective and presented as quality-adjusted life-years. Costs were from the perspective of the public sector, defined as NHS England, and the costs of special educational needs. All costs and quality-adjusted life-years were discounted by 3.5% per annum and the reference case time horizon was 20 years.

RESULTS

Umbilical artery Doppler flow velocimetry, cerebroplacental ratio, severe oligohydramnios and borderline oligohydramnios were all either non-predictive or weakly predictive of the risk of neonatal morbidity (summary positive likelihood ratios between 1 and 2) and were all weakly predictive of the risk of delivering a small for gestational age infant (summary positive likelihood ratios between 2 and 4). Suspicion of fetal macrosomia is strongly predictive of the risk of delivering a large infant, but it is only weakly, albeit statistically significantly, predictive of the risk of shoulder dystocia. Very few studies blinded the result of the ultrasound scan and most studies were rated as being at a high risk of bias as a result of treatment paradox, ascertainment bias or iatrogenic harm. Health economic analysis indicated that universal ultrasound for fetal presentation only may be both clinically and economically justified on the basis of existing evidence. Universal ultrasound including fetal biometry was of borderline cost-effectiveness and was sensitive to assumptions. Value-of-information analysis indicated that the parameter that had the largest impact on decision uncertainty was the net difference in cost between an induced delivery and expectant management.

LIMITATIONS

The primary literature on the diagnostic effectiveness of ultrasound in late pregnancy is weak. Value-of-information analysis may have underestimated the uncertainty in the literature as it was focused on the internal validity of parameters, which is quantified, whereas the greatest uncertainty may be in the external validity to the research question, which is unquantified.

CONCLUSIONS

Universal screening for presentation at term may be justified on the basis of current knowledge. The current literature does not support universal ultrasonic screening for fetal growth disorders.

FUTURE WORK

We describe proof-of-principle randomised controlled trials that could better inform the case for screening using ultrasound in late pregnancy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017064093.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 15. See the NIHR Journals Library website for further project information.

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.

Unconditional reference values for the amniotic fluid index measurement between 26w0d and 41w6d of gestation in low-risk pregnancies

OBJECTIVE

To establish reference values for the amniotic fluid index (AFI) measurement between 26w0d and 41w6d of gestation in a Brazilian population.

METHODS

We performed a cross-sectional study with 1984 low-risk singleton pregnant women between 26w0d and 41w6d of gestation. AFI was measured according to the technique proposed by Phelan et al. Maternal abdomen was divided into four quadrants using the umbilicus and linea nigra as landmarks. Single vertical pocket in each quadrant was measured and the AFI was generated by the sum of these four values without umbilical cord or fetal parts. All ultrasound exams were performed by only two experienced examiners. AFI was expressed as median, interquartile range, mean and ranges in each gestational age (GA) interval. Polynomial regressions were performed to obtain the best fit with adjustment by the determination coefficient (R(2)).

RESULTS

Mean of AFI ranged from 14.0 ± 4.1 cm (range, 9.7-14.0) at 26w0d to 8.3 ± 4.7 cm (range, 1.9-16.5) at 41w6d, respectively. The best polynomial regression fit curve was a first-degree: AFI = 16.29-0.125*GA (R(2) = 0.01). According the scatterplot, AFI values practically did not vary with advancing GA.

CONCLUSION

Reference values for the AFI measurement between 26w0d and 41w6d of gestation in a low-risk Brazilian population were established.