Comparability of the amniotic fluid index and single deepest pocket measurements in clinical practice

Post-obstructive diuresis after posterior urethral valve treatment in neonates: a retrospective cohort study

BACKGROUND

The management of posterior urethral valve (PUV) in neonates requires close monitoring in the intensive care unit because of the risk of post-obstructive diuresis (POD). Our aim was to describe the incidence and factors associated with POD in newborns treated for PUV.

METHODS

Retrospective analysis of the medical records of all neonates who underwent surgical intervention for PUV in our neonatal intensive care unit between January 2014 and April 2021.

RESULTS

Of the 40 patients included, 15 (37.5%) had POD defined by urine output > 6 ml.kg-1.h-1 during the first 24 h following urinary tract obstruction relief. At prenatal ultrasound examinations, oligohydramnios was more common in the group with POD than in the group without (53.3% vs. 8%, p = 0.002). Preterm birth was more frequent in neonates with POD (66.7% vs. 8%; p < 0.001). Median serum creatinine (212 [137-246] vs. 95 [77-125] µmol.l-1; p < 0.001) and urea (8.5 [5.2-12.2] vs. 4.1 [3.5-4.7] mmol.l-1; p < 0.001) concentrations on the day of obstruction relief were significantly higher in the group with POD than in the group without. After adjustment for prematurity, logistic regression models confirmed correlation between the occurrence of POD and the severity of the consequences of urethral obstruction (i.e., oligohydramnios and serum creatinine levels; ß = 2.90 [0.88; 5.36], p = 0.013 and ß = 0.014 [0.003; 0.031], p = 0.034, respectively).

CONCLUSIONS

In neonates, POD is common after the relief of PUV-related obstruction. Our findings may help to identify patients at highest risk. A higher resolution version of the Graphical abstract is available as Supplementary information.

Amniotic Fluid Disorders: From Prenatal Management to Neonatal Outcomes

Amniotic fluid volume assessment has become standard in the surveillance of fetal well-being, especially in high-risk pregnancies. Amniotic fluid disorders are a frequent and important topic in fetal and perinatal medicine. However, although important advances have been achieved, many important and challenging questions remain unanswered to date. An abnormally low amniotic fluid volume, referred to as oligohydramnios, has been traditionally considered a possible indicator of placental insufficiency or fetal compromise and is associated with an increased rate of obstetric interventions. An excess of amniotic fluid, referred to as polyhydramnios, may be secondary to fetal or maternal conditions and has been associated with a variety of adverse pregnancy outcomes, especially when it is severe. The ultrasonographic detection of an amniotic fluid disorder should prompt a proper workup to identify the underlying etiology. Data on the association of isolated oligohydramnios or idiopathic polyhydramnios with adverse obstetric and perinatal outcomes are conflicting. While the management of secondary oligohydramnios is usually guided by the underlying condition, the management of isolated oligohydramnios is poorly defined. Similarly, the management of idiopathic and secondary polyhydramnios is not yet standardized. There is an urgent need for randomized clinical trials to provide stronger recommendations on the management of these two common conditions.

Influence of maternal body mass index on interobserver variability of fetal ultrasound biometry and amniotic-fluid assessment in late pregnancy

OBJECTIVE

To determine the interobserver reproducibility of fetal ultrasound biometric and amniotic-fluid measurements in the third trimester of pregnancy, according to maternal body mass index (BMI) category.

METHODS

This was a prospective cohort study of women with a singleton gestation beyond 34 weeks, recruited into four groups according to BMI category: normal (18.0-24.9 kg/m² ), overweight (25.0-29.9 kg/m²⁾ , obese (30.0-39.9 kg/m² ) and morbidly obese (≥ 40 kg/m² ). Multiple pregnancies, women with diabetes and pregnancies with a fetal growth, structural or genetic abnormality were excluded. In each woman, fetal biometric (biparietal diameter (BPD), head circumference, abdominal circumference (AC), femur length (FL) and estimated fetal weight) and amniotic-fluid (amniotic-fluid index (AFI) and maximum vertical pocket (MVP)) measurements were obtained by two experienced sonographers or physicians, blinded to gestational age and each other's measurements. Differences in measurements between observers were expressed as gestational age-specific Z-scores. The interobserver intraclass correlation coefficient (ICC) and Cronbach's reliability coefficient (CRC) were calculated. Bland-Altman analysis was used to assess the degree of reproducibility.

RESULTS

In total, 110 women were enrolled prospectively (including 1320 measurements obtained by 17 sonographers or physicians). Twenty (18.2%) women had normal BMI, 30 (27.3%) women were overweight, 30 (27.3%) women were obese and 30 (27.3%) women were morbidly obese. Except for AFI (ICC, 0.65; CRC, 0.78) and MVP (ICC, 0.49; CRC, 0.66), all parameters had a very high level of interobserver reproducibility (ICC, 0.72-0.87; CRC, 0.84-0.93). When assessing reproducibility according to BMI category, BPD measurements had a very high level of reproducibility (ICC ≥ 0.85; CRC > 0.90) in all groups. The reproducibility of AC and FL measurements increased with increasing BMI, while the reproducibility of MVP measurements decreased. Among the biometric parameters, the difference between the BMI categories in measurement-difference Z-score was significant only for FL. Interobserver differences for biometric measurements fell within the 95% limits of agreement.

CONCLUSION

Obesity does not seem to impact negatively on the reproducibility of ultrasound measurements of fetal biometric parameters when undertaken by experienced sonographers or physicians who commonly assess overweight, obese and morbidly obese women. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Is There a Difference in Sonographic Estimation of Amniotic Fluid Volume When Measuring With the Probe Perpendicular to the Floor Compared With Perpendicular to the Uterine Contour?

OBJECTIVE

This study sought to determine whether there is a significant difference in amniotic fluid measurements when measuring perpendicular to the floor compared with perpendicular to the uterine contour using both amniotic fluid index and single deepest pocket.

METHODS

This was a single-centre, prospective study of women with singleton gestation who were undergoing fetal ultrasound examination. A total of 240 women were enrolled, and single deepest pocket and amniotic fluid index were measured with both techniques. Correlation coefficient and intraclass correlation coefficient were used to assess the agreement between the values using the two methods of measurement (Canadian Task Force Classification II-2).

RESULTS

A strong correlation was found between amniotic fluid index measurements (correlation coefficient 0.82; intraclass correlation coefficient 0.7). A strong correlation also was found between single deepest pocket measurements (correlation coefficient 0.7; intraclass correlation coefficient 0.6).

CONCLUSION

The measurement of amniotic fluid index and single deepest pocket can be performed either perpendicular to the floor or perpendicular to the uterine contour. There is no significant difference between these measurements and they correlate well.

Single deepest vertical pocket or amniotic fluid index as evaluation test for predicting adverse pregnancy outcome (SAFE trial): a multicenter, open-label, randomized controlled trial

OBJECTIVE

To determine whether the amniotic fluid index (AFI) or the single deepest vertical pocket (SDP) technique for estimating amniotic fluid volume is superior for predicting adverse pregnancy outcome.

METHODS

This was a multicenter randomized controlled trial including 1052 pregnant women with a term singleton pregnancy across four hospitals in Germany. Women were assigned randomly, according to a computer-generated allocation sequence, to AFI or SDP measurement for estimation of amniotic fluid volume. Oligohydramnios was defined as AFI ≤ 5 cm or the absence of a pocket measuring at least 2 × 1 cm. The diagnosis of oligohydramnios was followed by labor induction. The primary outcome measure was postpartum admission to a neonatal intensive care unit. Further outcome parameters were the rates of diagnosis of oligohydramnios and induction of labor (for oligohydramnios or without specific indication), and mode of delivery.

RESULTS

Postpartum admission to a neonatal intensive care unit was similar between groups (4.2% (n = 21) vs 5.0% (n = 25); relative risk (RR), 0.85 (95% CI, 0.48-1.50); P = 0.57). In the AFI group, there were more cases of oligohydramnios (9.8% (n = 49) vs 2.2% (n = 11); RR, 4.51 (95% CI, 2.2-8.57); P < 0.01) and more cases of labor induction for oligohydramnios (12.7% (n = 33) vs 3.6% (n = 10); RR, 3.50 (95% CI, 1.76-6.96); P < 0.01) than in the SDP group. Moreover, an abnormal cardiotocography was seen more often in the AFI group than in the SDP group (32.3% (n = 161) vs 26.2% (n = 132); RR, 1.23 (95% CI, 1.02-1.50); P = 0.03). The other outcome measures were not significantly different between the two groups.

CONCLUSIONS

Use of the AFI method increased the rate of diagnosis of oligohydramnios and labor induction for oligohydramnios without improving perinatal outcome. The SDP method is therefore the favorable method to estimate amniotic fluid volume, especially in a population with many low-risk pregnancies. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Twin-to-Twin Transfusion Syndrome: Definition, Staging, and Ultrasound Assessment

Objective: The purpose of this article is to review the definition of twin-to-twin transfusion syndrome (TTTS) and the sonographic diagnostic assessment of these cases prior to therapy.

Materials and Methods: The article addresses the terminology used to refer to the condition and describes the systematic ultrasound assessment of the condition, including the ultrasound diagnosis, the staging of the disease, cervical assessment and pre-operative mapping.

Results: From an etymologic and medical point of view, the term ‘fetofetal transfusion’ is more appropriate than ‘TTTS’. However, as the latter, and its attendant acronym TTTS, have been widely adopted in the English language, it is impractical to change at this point. TTTS is defined sonographically in the combined presence of a maximum vertical pocket (MVP) of 8 cm or greater in one sac and 2 cm or less in the other sac, regardless of the gestational age at diagnosis. Staging of the condition using the Quintero staging system is practical, reproducible, and accepted. Transvaginal cervical length assessment should be an integral part of the ultrasound evaluation. Pre-operative mapping to anticipate the location of the placental vascular anastomoses and avoid injuring the dividing membrane is also discussed.

Conclusions: The term ‘TTTS’ can continue to be used in the English medical literature. The condition can be diagnosed and assessed following a systematic ultrasound methodology. The use of such ultrasound methodology breaks the examination into a distinct set of components, assuring a comprehensive examination and proper communication among caregivers.

A comparison between amniotic fluid index and the single deepest vertical pocket technique in predicting adverse outcome in prolonged pregnancy

OBJECTIVE

to compare perinatal outcome in induced postterm pregnancies with normal amniotic volume and in patients with prolonged pregnancy undergone induction for oligohydramnios, evaluated by two different ultrasonographic methods.

METHODS

amniotic fluid volume was measured, using Single Deepest Vertical Pocket (SDVP) and Amniotic Fluid Index (AFI), in 961 singleton uncomplicated prolonged pregnancies. In 109 of these patients, hospitalization was planned for induction of labor, during or after 42 weeks of gestation, for oligohydramnios, postterm pregnancy and other indications in 47, 51 and 11 cases, respectively. Perinatal outcome included: rate of caesarean section, fetal distress, non reassuring fetal heart tracing, presence of meconium, umbilical artery pH < 7.1, Apgar score at 5 minutes < 7, admission to neonatal intensive care unit (NICU).

RESULTS

oligohydramnios was diagnosed in 4.89% of cases, when at least one of the two methods was used. A reduced AFI and SDVP value identified 4.47% and 3.75% of cases, respectively, even if without statistical difference. No statistical differences were reported in perinatal outcomes in postterm versus prolonged pregnancies with oligohydramnios, also in relation to the two different ultrasonographic methods.

CONCLUSIONS

oligohydramnios is more frequently diagnosed using AFI than SDVP, consequently determining a higher rate of induction of labor. Moreover, perinatal outcome in prolonged induced pregnancies is not affected by oligohydramnios.

Perinatal outcome after diagnosis of oligohydramnious at term

Background:

Oligohydramnious is threatening condition to fetal health for which some treatment are available and some are under evaluation. Oligohydramnious, is associated with increased pregnancy complication, congenital anomalies and perinatal mortality. There is an inverse relationship between the amniotic fluid index (AFI) and the adverse perinatal outcome. Oligo hydramnlious is clinical condition characteries by amniotic fluid index (AFI) of 5cm or less. Its incidence is 3-5 % of all the pregnancies an accurate and reproducible method of determining abnormality in amniotic fluid volume (AFI) is sonographic asessment of amniotic fluid index (AFI). It often increase the risk of small for gestational age (SGA) and also the incidence of cesarean section, meconium stained, low apgar score and Neonatal intensive care (NICU) admission.

Objectives:

The aim of study was to analyze the fetal out come in low risk pregnant women with oligohydramnious at term. This is a prospective, descriptive study.

Materials and Methods:

The study was conducted at Amiralmomenin hospital in Zabol for a period of 8 months from 2012/Mar/27 to 2012/Nov/5.It included 100 pregnant women diagnosed with the AFI of or less than 5cm at term. Control group included 300 pregnant women with AFI more than 8cm. Comparison was done between the study group and the control group. Regarding the fetal and pregnancy outcome using chi square and p value, detail were recorded in terms of fetal weight, apgar score at 1 and 5 minutes.

Results:

Mode of delivery, NICU admission neonatal death and induction of labour. Oligohydramnious is associated with a high rate of pregnancy complication and increased preinatal morbidity and mortality. Women with oligohydramnious usually have low birth babies.

Conclusions:

However, it can expect a safe and good outcome for which proper fetal surveillance and regular antenatal care visits are required.

Breech repositioning unresponsive to Webster technique: coexistence of oligohydramnios

OBJECTIVE

The purpose of this report is to describe the results of a pregnant woman demonstrating breech fetal presentation who was managed with Webster technique in the presence of oligohydramnios.

CLINICAL FEATURES

A 23-year-old primigravida woman sought chiropractic care for the management of breech presentation and bilateral sacroiliac arthralgia at 34 weeks' gestation.

INTERVENTION AND OUTCOME

Sacral manipulation and abdominal effleurage (Webster Technique) was used to address breech presentation and sacroiliac arthralgia for a total of 7 treatments over a 3 1/2-week duration. The patient's sacroiliac pain reduced from 8/10 to 3/10. However, breech presentation was unchanged at each treatment. At a scheduled prenatal surveillance during the 37th week of gestation, the midwife detected vaginal bleeding and reduced fundal height, which resulted in hospitalization, diagnosis of oligohydramnios, and an emergency cesarean delivery.

CONCLUSION

For this particular patient, the breech presentation was not corrected using the Webster technique. Clinicians who use the Webster technique to manage breech fetal presentation should be aware of undiagnosed comorbidities as a complicating factor in clinical presentation. Screening for previously undiagnosed comorbidities, such as oligohydramnios, must be considered.

[Management of post-term pregnancies: the role for AFI, biophysical score and doppler]

OBJECTIVE

To evaluate the role of ultrasound and doppler assessment in the management of prolonged pregnancies and to state its modalities.

METHOD

Medline, PubMed, embase and the Cochrane library were searched using terms prolonged pregnancy, post date pregnancy amniotic fluid, ultrasound assessment, doppler, biophysical profile.

RESULTS

Single deepest vertical pool measurement is the method of choice of the assessment of amniotic fluid. Indeed, when this method was used, significantly fewer case of oligohydramnios were diagnosed and fewer women had inductions of labor. However, this method is not superior to the amniotic fluid index in the prevention of poor perinatal outcomes. There is a significant difference in the incidence of fetal distress, meconium stained fluid and caesarean section for fetal distress when the amniotic fluid is reduced as compared with normal amniotic fluid. However, sensibility and predictive positive value of oligohydramnios to predict poor perinatal outcomes is moderate. Similary, in most studies, diagnosis of an abnormal uterine, umbilical, aortic or cerebral blood flow doppler was associated with a weak prediction of a poor perinatal outcome. Therefore, we do not recommend its use in management of prolonged pregnancy. There were significantly more diagnosis of oligoamnios and more abnormal antenatal monitoring results in the modified biophysical profile group as compared with the group managed with only single deepest pool but no differences in cord blood gases, neonatal outcome, or in outcomes related to labour and delivery were noted between the two groups. Therefore, biophysical profile including AFI offers no advantage in detecting adverse outcomes and may cause more interventions.

CONCLUSION

Close monitoring of fetal condition including assessment of amniotic fluid by single deepest pool twice a week from 41 weeks of gestation is recommended in the management of prolonged pregnancy. Induction of labor could be considered when oligohydramnios is diagnosed by single deepest pool less than 2 cm.

Amniotic fluid index versus single deepest vertical pocket: a meta-analysis of randomized controlled trials

OBJECTIVE

To compare the use of the amniotic fluid index with the single deepest vertical pocket measurement, during antepartum fetal surveillance, in preventing adverse pregnancy outcome.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2008), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 2), MEDLINE (1966 to May 2008), and the metaRegister of Controlled Trials (May 2008). We handsearched the citation lists of relevant publications, review articles, and included studies.

SELECTION CRITERIA

Randomized controlled trials involving women with a singleton pregnancy, whether at low or high risk, undergoing ultrasound measurement of amniotic fluid volume as part of antepartum assessment of fetal well-being that compared the amniotic fluid index and the single deepest vertical pocket measurement.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed eligibility and quality, and extracted the data.

RESULTS

Four trials (3125 women) met the inclusion criteria. When the amniotic fluid index was used, significantly more cases of oligohydramnios were diagnosed (risk ratio (RR) 2.33, 95% CI 1.67-3.24), and more women had inductions of labor (RR 2.10, 95% CI 1.60-2.76) and cesarean delivery for fetal distress (RR 1.45, 95% CI 1.07-1.97). There is no evidence that one method is superior to the other in the prevention of poor peripartum outcomes, including: admission to a neonatal intensive care unit; an umbilical artery pH of less than 7.1; the presence of meconium; an Apgar score of less than 7 at 5 minutes; or cesarean delivery.

CONCLUSION

Single deepest vertical pocket measurement is the method of choice for the assessment of amniotic fluid volume.

Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome

BACKGROUND

Amniotic fluid volume is an important parameter in the assessment of fetal well-being. Oligohydramnios occurs in many high-risk conditions and is associated with poor perinatal outcomes. Many caregivers practice planned delivery by induction of labor or caesarean section after diagnosis of decreased amniotic fluid volume at term. There is no clear consensus on the best method to assess amniotic fluid adequacy.

OBJECTIVES

To compare the use of the amniotic fluid index with the single deepest vertical pocket measurement as a screening tool for decreased amniotic fluid volume in preventing adverse pregnancy outcome.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2008), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to May 2007) and the metaRegister of Controlled Trials (May 2007). We handsearched the citation lists of relevant publications, review articles, and included studies.

SELECTION CRITERIA

Randomised controlled trials involving women with a singleton pregnancy, whether at low or high risk, undergoing ultrasound measurement of amniotic fluid volume as part of antepartum assessment of fetal well-being that compared the amniotic fluid index and the single deepest vertical pocket measurement.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed eligibility and quality, and extracted the data.

MAIN RESULTS

Four trials (3125 women) met the inclusion criteria. There is no evidence that one method is superior to the other in the prevention of poor peripartum outcomes, including: admission to a neonatal intensive care unit; an umbilical artery pH of less than 7.1; the presence of meconium; an Apgar score of less than 7 at five minutes; or caesarean delivery. When the amniotic fluid index was used, significantly more cases of oligohydramnios were diagnosed (risk ratio (RR, random) 2.33, 95% CI 1.67 to 3.24), and more women had inductions of labor (RR (fixed) 2.10, 95% CI 1.60 to 2.76) and caesarean delivery for fetal distress (RR (fixed) 1.45, 95% CI 1.07 to 1.97).

AUTHORS' CONCLUSIONS

The single deepest vertical pocket measurement in the assessment of amniotic fluid volume during fetal surveillance seems a better choice since the use of the amniotic fluid index increases the rate of diagnosis of oligohydramnios and the rate of induction of labor without improvement in peripartum outcomes. A systematic review of the diagnostic accuracy of both methods in detecting decreased amniotic fluid volume is required.

Antenatal fetal surveillance

PURPOSE OF REVIEW

Antenatal fetal surveillance is a field of increasing importance in modern obstetrics, especially as results in perinatal care have recently made dramatic progress. It is an evolving field, and it is no longer acceptable just to wait and see when problems arise in pregnancy. During the past few decades many studies have shown that antenatal surveillance in unselected populations is of little value. However, high-risk patients benefit from antenatal fetal surveillance, especially women with pregnancy problems associated with intrauterine growth restriction.

RECENT FINDINGS

This review shows that modern antenatal fetal surveillance is based on fetal heart rate monitoring, ultrasound biometry and amniotic fluid assessment, Doppler blood flow studies of fetal and uteroplacental circulation, and an evaluation of biophysical fetal parameters.

SUMMARY

Used in combination these methods lead to improvements in fetal morbidity and mortality. The aim of future research should be to minimize the risks of fetal morbidity and mortality further by the optimal timing of delivery. Better organization of healthcare systems may improve our ability to identify at-risk patients during pregnancy. There is potential to improve the specificity of fetal surveillance tests, e.g. better methods of biometry and amniotic volume estimation with three-dimensional ultrasound and measurements of subcutaneous tissue. Improved knowledge of fetal physiology can be gained from research on fetal circulation with Doppler studies. Computer analysis of the fetal heart rate can increase the specificity of that test, and artificial neural networks may enhance the ability to evaluate the optimal use of integrated testing.

Is amniotic fluid volume status predictive of fetal acidosis at delivery?

OBJECTIVE

To ascertain if dye-determined amniotic fluid volume just prior to delivery correlates with fetal acidosis at delivery.

DESIGN

The present was a prospective observational study.

SETTING

The study took place at the University of Mississippi Medical Center, Jackson MS, USA.

POPULATION

The population included 100 unlaboured women undergoing an amniocentesis for the assessment of fetal lung maturity before an elective Caesarean delivery between January 1997 and December 2000.

MAIN OUTCOMES MEASURED

The amniotic fluid volume was estimated by ultrasound measurement and quantified by dye-determined methodology immediately prior to Caesarean delivery. Umbilical cord artery pH was collected at the time of Caesarean delivery.

RESULTS

The predictive accuracy of an amniotic fluid index < or = versus > 5 to identify an umbilical artery pH of < 7.20 had a sensitivity of 0%, a specificity of 84%, and a likelihood ratio of zero. None of the dye-determined low amniotic fluid volumes were identified using the single deepest pocket technique. Dye-determined low, normal, and high amniotic fluid volume groups contained a similar number of fetuses with umbilical cord arterial pH < 7.20 (P = 0.371), < 7.10 (P = 0.460), and < 7.00 (P = 0.614). Receiver-operating characteristic curves could not identify any amniotic fluid index from 0 to 18, single deepest pocket from 0 to 12, or dye-determined amniotic fluid volume 100-1900 mL to differentiate between the two newborns with an umbilical cord artery pH < 7 from 98 babies with cord pH > or = 7.0.

CONCLUSIONS

Neither ultrasound estimates nor dye-determined amniotic fluid volumes are predictive of a low umbilical artery pH at delivery.