Visualization of fetal intra-abdominal organs in second-trimester severe oligohydramnios by intraperitoneal infusion

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.

Oligohydramnios and associated fetal complications

During intrauterine life the fetus is bathed in amniotic fluid which provides a low resistance space for free movement and a buffer against external trauma. This fluid is produced in early pregnancy largely as a maternal dialysate, then as a fetal transudate. Fetal urine is the most important source of amniotic fluid after 16 weeks gestation. The control of amniotic fluid is complex and poorly understood; it arises from secondary partitioning of water within the fetoplacental extracellular space and reflects fetal fluid balance.

Invasive prenatal diagnostic techniques

Subspecialization in fetal medicine has expanded the scope for obstetricians to investigate the fetus and its surrounding environment in greater detail. Of the advances in technology that have made this possible, ultrasonography is the most important. A high degree of skill is required if it is to be applied to the performance of invasive diagnostic techniques. These should be performed only in specialized centres with appropriate facilities and an adequate referral base. However, it is important for obstetricians to know what is possible in the field of prenatal diagnosis and therapy in order to give patients the best advice.

Prenatal diagnosis and management of abnormalities in the urologic system

We have reviewed the prenatal diagnosis and management of abnormalities in the urologic system. Urologic anomalies may be caused by embryologic aberrations, genetic disease, or a nonrandom association with other structural abnormalities. There is a wide range of prognoses, depending on the cause and the impact of the anomaly on the production of amniotic fluid. Management focuses on obtaining an accurate prenatal diagnosis, providing appropriate counseling, and ensuring the proper surveillance or treatment before and after birth.

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.

The use of saline solution as a contrast medium in suspected diaphragmatic hernia and renal agenesis

OBJECTIVE

Our purpose was to determine the value of saline solution instillation as a contrast medium in suspected congenital diaphragmatic hernia and renal agenesis.

STUDY DESIGN

Intrathoracic (n = 3) or intraperitoneal (n = 2) instillation was performed in five cases of suspected congenital diaphragmatic hernia. Amnioinfusion combined with intraperitoneal instillation was performed in five cases of suspected renal agenesis.

RESULTS

Instillation clearly demonstrated the diaphragmatic defect in four of the five cases. In the cases with suspected renal agenesis, amnioinfusion led to recognition of a previously unsuspected sirenomelia, and intraperitoneal instillation demonstrated empty renal fossae in four cases. The final fetus with bilateral renal agenesis was thought antenatally to have a contralateral multicystic kidney.

CONCLUSIONS

We suggest that intrathoracic or intraperitoneal saline solution instillation is a useful diagnostic procedure in carefully selected cases where confident ultrasonic diagnosis is often difficult and yet would significantly alter management. In cases of severe oligohydramnios amnioinfusion is a complementary procedure. In 80% of cases in this series there was significant improvement in visualization after the procedure.

A case report: vesico-rectal fistula with ano-urethral atresia

Vesico-rectal fistula is a rare congenital abnormality causing severe early second trimester oligohydramnios. Prenatal diagnosis of such a case is reported here. Ultrasound diagnosis could be aided by transabdominal amnio-infusion and, if necessary, fetal intraperitoneal saline installation. In a karyotypically normal fetus with normal somatic growth, demonstration of normal fetal kidneys together with a functioning urinary bladder, in presence of severe oligohydramnios, is very suggestive of the diagnosis. Since pulmonary hypoplasia is the major cause of neonatal mortality in these cases, restoration of normal amniotic fluid volume by serial amnio-infusion was attempted. Although amnio-infusion is an important diagnostic aid in the evaluation of severe midtrimester oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth remains to be evaluated.

Cystic lesions of the fetal kidney: diagnosis and prediction of postnatal function by fetal urine biochemistry

Fetal urine was aspirated under ultrasound control from 21 large cystic renal masses in 18 pregnancies of 20 to 35 weeks gestation. None were associated with bladder or ureteric dilatation. At postnatal investigation, 12 kidneys were demonstrated to be hydronephrotic (5 with no or poor function) and 9 multicystic. Urinary concentrations of sodium (Na+), calcium (Ca++), and phosphate (PO4--) were significantly higher in the multicystic group than in the hydronephrotic, whereas urea and creatinine levels were lower. Determination of urinary PO4-- enabled differential diagnosis with no false-positive or false-negative cases. Among hydronephrotic kidneys, no biochemical parameter accurately predicted postnatal function, although creatinine was increased in all three nonfunctioning kidneys. In hydronephrotic kidneys, urinary Na+ concentration increased with advancing gestational age (r = .66; P < .02), suggesting that the duration of hydronephrosis has a negative effect on renal function.

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

OBJECTIVE

Amnioinfusion was used in pregnancy complicated by severe oligohydramnios to enable a more comprehensive ultrasonographic evaluation of the pregnancy.

STUDY DESIGN

Thirteen patients were referred to the Division of Obstetrical and Gynecological Ultrasound at the University of Miami because of severe oligohydramnios in which a definitive diagnosis could not be made. Nine patients were in the second trimester and four were in the early third trimester. All patients underwent amnioinfusion with warm physiologic saline solution and instillation of indigo carmine. Genetic amniocentesis was performed in 11 patients.

RESULTS

After amnioinfusion a satisfactory comprehensive ultrasonographic examination could be performed on all patients. In most cases we were able to achieve a definitive diagnosis.

CONCLUSION

Amnioinfusion with the addition of indigo carmine was a satisfactory technique to enable a more comprehensive ultrasonographic evaluation of pregnancy complicated by severe oligohydramnios.

Fetal blood sampling from the intrahepatic vein for rapid karyotyping in the second and third trimesters

One hundred and twelve fetuses with structural anomalies (n = 84), intrauterine growth retardation (n = 21) or amniotic fluid volume disorders (n = 7) detected by ultrasound underwent blood sampling from the intrahepatic vein for rapid karyotyping. The procedure was successful in 95.5%. 12.5% of the fetuses had an abnormal karyotype. Fetal bradycardia was observed in two fetuses (1.8%) and intraperitoneal bleeding in three (2.7%). There were three procedure-related losses but these were not due to the intrahepatic vein sampling itself. Fetal blood sampling is the method of choice for rapid karyotyping in the second and third trimesters, and the intrahepatic vein is an alternate site when access is difficult or failure to sample occurs at the placental cord insertion. Additional advantages of fetal blood sampling at the intrahepatic vein include absence of cord complications, reduced risk of fetal blood loss and fetomaternal haemorrhage, and the lack of need to confirm the fetal origin of the sample.