Amnioinfusion: an aid in the ultrasonographic evaluation of severe oligohydramnios in pregnancy

Observed to expected lung area to head circumference ratio (O/E LHR) in fetuses with congenital anomalies of the kidney and urinary tract (CAKUT): assessment and evaluation as predictive factor for acute postnatal outcome-a single center study

Introduction

To assess the observed to expected lung area to head circumference ratio (O/E LHR) in fetuses with congenital anomalies of the kidney and urinary tract (CAKUT) and to explore its value as a potential predictive factor for postnatal outcome.

Methods

A retrospective single-center study was conducted on pregnancies complicated by CAKUT between 2007 and 2018. The lung-to-head ratio (LHR) was calculated for each fetus by two independent observers. Correlations between O/E LHR and various perinatal outcome factors were assessed with Spearman's rank correlation. Furthermore, nominal logistic regression was performed to assess O/E LHR as predictive factor for respiratory distress in newborn.

Results

Of 64 pregnancies complicated by CAKUT, 23 were terminated. In the 41 cases of continuation of pregnancy, newborn presenting respiratory distress with need for respiratory support in the delivery room showed earlier gestational age at onset of amniotic fluid abnormalities and at birth. Although median O/E LHR and median single deepest pocket (SDP) of amniotic fluid were significantly smaller in newborn that did develop respiratory distress with need of respiratory support in the delivery room, neither O/E LHR nor SDP were accurate predictors for the development of respiratory distress.

Conclusions

Our data show that O/E LHR alone cannot serve as a predictive marker for fetal outcome in pregnancies complicated by CAKUT, though it might still be a helpful parameter together with detailed renal ultrasound evaluation, onset of amniotic fluid abnormality and SDP, particularly in its extreme values.

Impact of antepartum diagnostic amnioinfusion on targeted ultrasound imaging of pregnancies presenting with severe oligo- and anhydramnios: An analysis of 61 cases

OBJECTIVES

The primary objective our study was to assess the role of diagnostic antepartum amnioinfusion on the yield from targeted ultrasounds performed in pregnancies with severe oligo- and anhydramnios.

STUDY DESIGN

This was a retrospective and descriptive study, conducted in the fetal medicine units of two private tertiary care referral centers in south India. The details of all the cases of diagnostic amnioinfusion performed at these two centers from January 2009 to June 2016 were collected and analyzed. Inclusion criteria were pregnancies between 17 and 26 weeks of gestational age with severe oligo- or anhydramnios. Pregnancies with obvious preterm premature rupture of membranes (PPROM) were excluded. The primary outcome measure was the improvement in diagnostic information pertaining to cause of severe oligo- and anhydramnios, and the nature of such anomalies.

RESULTS

A total of 61 cases of were identified. The median gestational age at performance of the procedure was 22 weeks [IQR, 19.5-23]. The mean volume of normal saline infused was 314±54ml. A significant increase in the single vertical pocket (SVP) was observed following the procedure (pre-procedure SVP=0.6±0.9cm, post procedure SVP=3.4±1.7; paired t test, p<0.001). In 37 cases (37/61, 60.7%), there were no pre-procedure ultrasound findings. There was significant overall detection of abnormalities post procedure (mean pre-procedure findings=0.39±0.49, mean post procedure findings=1.59±1.24; paired t test, p<0.001). The most frequent group of anomalies/abnormalities were renal (36/61, 59%), followed by PPROM (13/61, 21.3%) and finally fetal growth restriction (11/61, 18%).

CONCLUSION(S)

Antepartum amnioinfusion is a valuable ancillary technique in prenatal diagnosis as it increases the diagnostic yield from pregnancies presenting with severe oligo- and anhydramnios.

Caudal Regression Syndrome

Caudal regression syndrome (CRS), also known as caudal dysplasia syndrome, is a rare malformation that ranges from mild coccygeal to severe forms of lumbosacral and lower thoracic agenesis. Anomalies of other organ systems may also be found simultaneously. Recognition of CRS is important as the extent of abnormality and gestational age could determine the pregnancy’s outcome. Antenatal diagnosis is possible by recognizing the characteristic features on sonography. In this particular case study, a diagnosis of CRS was made during the second trimester with sonography and resulted in an adequate medical management decision. The sonographic features of CRS and its differential diagnoses are discussed in the context of this case study.

Antepartum amnioinfusion: a review

OBJECTIVE

Antepartum amnioinfusion is a relatively recent procedure introduced with fetal medicine techniques. It is usually indicated for severe oligohydramnios in order to avoid the related complications such as pulmonary hypoplasia, the deforming effects of oligohydramnios, variable fetal heart rate decelerations and intraventricular hemorrhage. Antepartum amnioinfusion is also employed to improve ultrasound visualization in cases with oligohydramnios. Our objective was to evaluate the benefits and complications related to this procedure which is still less commonly used compared to intrapartum amnioinfusion, and whose risks are therefore not well established.

STUDY DESIGN

Reports of study designs identified from searches of MEDLINE, PUBMED, the Cochrane Collaboration, specialized databases and bibliographies of review articles were identified. Studies in women who underwent amnioinfusion between 1987 and 2002 were included.

RESULTS AND CONCLUSIONS

Amnioinfusion seems to offer several benefits, in terms of both prenatal diagnosis and favorable perinatal outcome. Most clinical experiences report that amnioinfusion is safe, both for the mother and for the fetus. However, randomized control-group studies subdivided on the basis of the cause of oligohydramnios (e.g. premature rupture of membranes, fetal growth restriction, obstructive uropathy and renal agenesis) could help to determine the advantages and risks linked to this procedure. Prospective randomized studies should therefore be encouraged, to clarify any possible doubts regarding the procedure, before it can be introduced into routine practice in the management of oligohydramnios.

Prenatal diagnosis of Caudal Regression Syndrome : a case report

BACKGROUND: Caudal regression is a rare syndrome which has a spectrum of congenital malformations ranging from simple anal atresia to absence of sacral, lumbar and possibly lower thoracic vertebrae, to the most severe form which is known as sirenomelia. Maternal diabetes, genetic predisposition and vascular hypoperfusion have been suggested as possible causative factors. CASE PRESENTATION: We report a case of caudal regression syndrome diagnosed in utero at 22 weeks' of gestation. Prenatal ultrasound examination revealed a sudden interruption of the spine and "frog-like" position of lower limbs. Termination of pregnancy and autopsy findings confirmed the diagnosis. CONCLUSION: Prenatal ultrasonographic diagnosis of caudal regression syndrome is possible at 22 weeks' of gestation by ultrasound examination.

Clinical role of amnio-infusion

Amnio-infusion is a simple, yet beneficial, technique for improving pregnancy outcome. Antepartum amnio-infusion has been shown to be beneficial as an aid to enhancing ultrasonographic fetal imaging and may have a role in the administration of antibiotic therapy or the prevention of pulmonary hypoplasia. There are considerable data to support the intrapartum use of amnio-infusion in the presence of oligohydramnios, variable decelerations or meconium. Numerous prospective clinical trials have shown a significant benefit of amnio-infusion in reducing the rate of emergency caesarean section for fetal distress and complications related to meconium when used for these indications. Additional research is needed to clarify further its intrapartum role in patients with premature rupture of membranes or chorio-amnionitis.

Accuracy of prenatal diagnosis of renal agenesis with color flow imaging in severe second-trimester oligohydramnios

OBJECTIVE

Our purpose was to examine the potential of color flow imaging to assess the presence of renal arteries in second-trimester pregnancies complicated by severe oligohydramnios.

STUDY DESIGN

Thirty-three consecutive second-trimester pregnancies referred with severe oligohydramnios were prospectively studied with high-resolution color Doppler ultrasonography to establish the presence or absence of renal arteries. Prenatal findings were correlated with the presence or absence of fetal kidneys at postmortem or postnatal examination.

RESULTS

Neither renal artery was visualized in eight fetuses; postmortem examination confirmed bilateral renal agenesis in seven and unilateral renal agenesis with a contralateral atrophic multicystic kidney in the other. Only one renal artery was seen in three; postmortem examination demonstrated unilateral renal agenesis in two fetuses and bilateral multicystic dysplastic kidneys in the other. Postmortem or postnatal evaluation confirmed the presence of both kidneys in all 22 fetuses in which both renal arteries were identified prenatally.

CONCLUSIONS

Color Doppler ultrasonography is useful in the prenatal evaluation of fetuses with severe second-trimester oligohydramnios to demonstrate the presence or absence of renal arteries. This technique should be added to the armamentarium of prenatal tests to evaluate second-trimester fetuses with severe oligohydramnios.