ISUOG Practice Guidelines: intrapartum ultrasound

The purpose of these Guidelines is to review the published techniques of ultrasound in labor and their practical applications, to summarize the level of evidence regarding the use of ultrasound in labor and to provide guidance to practitioners on when ultrasound in labor is clinically indicated and how the sonographic findings may affect labor management. We do not imply or suggest that ultrasound in labor is a necessary standard of care.

Cranial and cerebral signs in the diagnosis of spina bifida between 18 and 22 weeks of gestation: a German multicentre study

OBJECTIVE

The aim of this article is to study secondary cranial signs in fetuses with spina bifida in a precisely defined screening period between 18 + 0 and 22 + 0 weeks of gestation.

METHOD

On the basis of retrospective analysis of 627 fetuses with spina bifida, the value of indirect cranial and cerebral markers was assessed by well-trained ultrasonographers in 13 different prenatal centres in accordance with the ISUOG (International Society of Ultrasound in Obstetrics and Gynecology) guidelines on fetal neurosonography.

RESULTS

Open spina bifida was diagnosed in 98.9% of cases whereas 1.1% was closed spina bifida. Associated chromosomal abnormalities were found in 6.2%. The banana and lemon signs were evident in 97.1% and 88.6% of cases. Obliteration of the cisterna magna was seen in 96.7%. Cerebellar diameter, head circumference and biparietal diameter were below the 5th percentile in chromosomally normal fetuses in 72.5%, 69.7% and 52%, respectively. The width of the posterior horn of the lateral ventricle was above the 95th percentile in 57.7%. The secondary cranial and cerebral signs were dependent on fetal chromosome status and width of the posterior horn. Biparietal diameter was also dependent on the chromosome status with statistical significance p = 0.0068. Pregnancy was terminated in 89.6% of cases.

CONCLUSION

In standard measuring planes, lemon sign, banana sign and an inability to image the cistern magna are very reliable indirect ultrasound markers of spina bifida. © 2014 John Wiley & Sons, Ltd.

Prenatal diagnosis of membranous ventricular septal aneurysms and their association with absence of atrioventricular valve 'offsetting'

Congenital aneurysm of the membranous portion of the ventricular septum in association with absence of atrioventricular valve 'offsetting' was diagnosed in two fetuses at 29 and 34 weeks. In the first case the fetus had a normal karyotype and no other structural heart defects, whereas in the second case there was a partial deletion of the long arm of chromosome 5 and an absent pulmonary valve syndrome. The association of absence of 'offsetting' with aneurysms of the membranous ventricular septum may represent spontaneous closure of ventricular septal defects initially extended to the inlet.

Elevated monocyte chemotactic protein-1 in amniotic fluid is a risk factor for pregnancy loss

OBJECTIVE

Pregnancy loss after mid-trimester amniocentesis occurs in 0.5-1% of cases and is frequently attributed to the procedure. Accumulating evidence implicates a pre-existing, but clinically silent, intra-amniotic inflammation in the etiology of adverse pregnancy outcome after mid-trimester amniocentesis. Monocyte chemotactic protein-1 (MCP-1) is a potent chemokine produced by a wide variety of cells during the course of an inflammatory response. This study was designed to assess if the amniotic fluid concentration of this chemokine identifies patients at risk for spontaneous abortion and/or fetal death.

METHOD

A retrospective case-control study of women who had a mid-trimester amniocentesis was designed. Cases (n = 10) consisted of patients who had a spontaneous pregnancy loss after the procedure, while the control group (n = 84) consisted of patients who had a normal pregnancy outcome after mid-trimester amniocentesis. MCP-1 was measured by a specific enzyme immunoassay (sensitivity, 18.3 pg/ml). The Kolmogorov-Smirnov test was utilized to assess normal distribution of the data. Logarithmic transformation was applied to achieve normality. Statistical analysis was performed using Student's t test. A receiver operating characteristic (ROC) curve analysis was used to select a cut-off to dichotomize amniotic fluid concentrations of MCP-1.

RESULTS

MCP-1 was detectable in all amniotic fluid samples. Patients who had a mid-trimester amniocentesis and a subsequent pregnancy loss had a higher mean amniotic fluid log MCP-1 concentration than those with a normal pregnancy outcome (pregnancy loss, mean 2.95 +/- 0.19 pg/ml vs. normal outcome, mean 2.78 +/- 0.19 pg/ml; p = 0.01). A cut-off of > 765 pg/ml was selected by ROC curve analysis (area under the curve, 0.74; p = 0.01). An amniotic fluid concentration of MCP-1 above this level was strongly associated with pregnancy loss (odds ratio, 7.35; 95% confidence interval, 1.7-31.1), a sensitivity of 70%, and a specificity of 76%.

CONCLUSION

A subset of women who had a pregnancy loss after a mid-trimester amniocentesis had higher concentrations of the chemokine MCP-1 than those who had a normal pregnancy outcome. Subclinical intra-amniotic inflammation is a risk factor for pregnancy loss after mid-trimester amniocentesis. This observation may have medicolegal and clinical implications. An elevated MCP-1 concentration in amniotic fluid of patients with a pregnancy loss after a mid-trimester amniocentesis indicates that a pathological condition was present at the time of the procedure.

Soluble adhesion molecule profile in normal pregnancy and pre-eclampsia

OBJECTIVE

An exaggerated inflammatory response has been implicated as the cause of endothelial cell dysfunction and the maternal syndrome of pre-eclampsia. Adhesion molecules play a central role in the adherence of leukocytes to endothelial cells and the subsequent migration of white blood cells into perivascular tissue. Cellular forms of adhesion molecules mediate specific steps of leukocyte-endothelial cell interaction, and have been implicated in the pathophysiology of preeclampsia. Soluble forms of these molecules can be detected in plasma, and their concentrations are thought to reflect the degree of activation of a particular cell type. Elevations in soluble P-selectin (sP-selectin) reflect platelet activation; changes in soluble L-selectin (sL-selectin) suggest leukocyte activation; and an increase in soluble forms of E-selectin (sE-selectin), vascular cell adhesion molecule 1 (sVCAM-1), intercellular adhesion molecule 1 (sICAM-1) and platelet endothelial cell adhesion molecule (sPECAM-1) indicate endothelial cell activation/dysfunction. The objective of this study was to determine whether normal pregnancy and pre-eclampsia were associated with changes in the concentrations of soluble selectins and members of the immunoglobulin superfamily of adhesion molecules.

STUDY DESIGN

A cross-sectional study was conducted to determine the plasma concentrations of sL-selectin, sE-selectin, sP-selectin, sVCAM-1, sICAM-1 and sPECAM-1 in peripheral blood obtained from non-pregnant women (n = 20), normal pregnant women (n = 100) and patients with pre-eclampsia (n = 55). Concentrations of soluble adhesion molecules were determined with enzyme-linked immunoassays. Parametric statistics were used for data analysis.

RESULTS

Normal pregnancy was associated with a significant increase in the maternal plasma concentration of sP-selectin, a decrease in sL-selectin, and no change in sE-selectin, sVCAM-1, sICAM-1 and sPECAM-1. In contrast, pre-eclampsia was associated with a significant increase in sP-selectin, sE-selectin and sVCAM-1, a decrease in sL-selectin, but no change in sICAM-1 and sPECAM-1 concentrations.

CONCLUSIONS

The increased concentration of sP-selectin and decreased sL-selectin, as well as the lack of change in endothelial cell-associated soluble adhesion molecules suggest that pregnancy is associated with platelet and leukocyte activation, but not endothelial cell activation. In contrast, pre-eclampsia appears to be characterized by activation of platelets, leukocytes and endothelial cells.

Subclinical myocardial injury in small-for-gestational-age neonates

OBJECTIVE

Small-for-gestational-age (SGA) infants are at risk for premature death from cardiovascular disease (myocardial infarction and stroke), hypertension, and diabetes in adult life. Severe intrauterine growth restriction is often associated with subclinical cardiovascular abnormalities detectable during fetal echocardiography. The objective of this study was to determine whether SGA newborns have evidence of myocardial injury at birth.

STUDY DESIGN

Cardiac troponin I, a specific marker of myocardial injury widely used for the diagnosis of myocardial infarction in adults, was determined in umbilical cord blood. Umbilical cord venous blood was obtained at the time of birth from 72 SGA newborns (birth weight below the 10th centile for gestational age) and 309 newborns whose birth weights were appropriate for gestational age (AGA). Cardiac troponin I was determined with a commercially available immunoassay (sensitivity 0.2 ng/ml) employed in clinical laboratories (Immulite 2000, Diagnostic Products Corp., Los Angeles, CA).

RESULTS

Cardiac troponin I was not detectable in any of the blood samples from AGA infants. In contrast, 4.2% (3/72) of SGA infants had detectable cardiac troponin I in umbilical cord blood (Fisher's exact test, p = 0.007).

CONCLUSION

A subgroup of SGA newborns undergoes myocardial injury before birth. This insult may predispose to the development of adult premature cardiovascular disease and death.

Prenatal diagnosis of intrahepatic communications of the umbilical vein with atypical arteries (A-V fistulae) in two cases of trisomy 21 using color Doppler ultrasound

We report on two cases of the prenatal diagnosis of arterio-venous communication between the intra-abdominal umbilical vein and atypical arteries. The diagnosis was made by color and spectral Doppler and 'color power angiography'. Both cases presented with hydrops fetalis, one at 14 and the other at 31 weeks of gestation. In the first case, color Doppler demonstrated an atypical arterial vessel connecting the umbilical vein with the aorta; the ductus venosus was patent. Echocardiography showed a so-called atrioventricular canal. In the second case, a complex intrahepatic vascular malformation was found. Color Doppler demonstrated communications between the umbilical vein and the hepatic artery and an atypical artery; the ductus venosus was patent. In the latter case polyhydramnios, duodenal atresia and macroglossia were additionally detected. In both cases, fetal karyotyping revealed trisomy 21. The first case resulted in a missed abortion, the second in a stillbirth. All findings were confirmed on autopsy. Of interest is that both fetuses were affected with trisomy 21. The increasing use of color Doppler in prenatal diagnosis, especially in hemodynamically compromised fetuses, will help to determine the actual incidence of complex vascular malformations of the umbilical vein and to elucidate the impact of such malformations on fetal outcome.

Pulmonary arterial Doppler velocimetry in fetuses with lung hypoplasia

OBJECTIVE

The aim of the study was to examine Doppler flow velocity waveforms in the main stems of the pulmonary arteries in fetuses with autopsy-proven lung hypoplasia and to find out whether in these conditions typical patterns can be found.

STUDY DESIGN

Doppler spectra were derived from the main stem of the right or left pulmonary artery in fetuses at high-risk for lung-hypoplasia. The following Doppler parameters were analyzed and compared to reference ranges: peak systolic velocity, acceleration time, time velocity integral, end-systolic reverse flow, pulsatility index (PI). Pulmonary hypoplasia was found in nine cases at autopsy after termination of pregnancy (19-23 weeks). According to etiology, three groups were considered: (A) bilateral renal malformations (n=4), (B) congenital diaphragmatic hernia (n=2), and (C) miscellaneous malformations including heart defects (n=3).

RESULTS

The following Doppler parameters were found: normal values in end-systolic reversal flow in all cases, decreased peak systolic velocity and acceleration time in 3/9, decreased time velocity integral in 4/9 and increased pulsatility index in 6/9. Considering the etiology of pulmonary hypoplasia the pulsatility index was found to be the most sensitive, since all fetuses in groups A and B had an abnormal PI.

CONCLUSIONS

Human fetuses with renal malformations and diaphragmatic hernia associated with lung hypoplasia show as early as 19-23 weeks of gestation an abnormal Doppler spectrum in the main stems of the pulmonary arteries. Increased PI is the best parameter to detect flow abnormality in this condition. Since the Doppler spectrum depends on cardiac anatomy and function, PI in lung hypoplasia seems to be reliable only when cardiac defects are absent.

[Ultrasound biometry of the fetal lung--measurement planes and reference values]

The aim of the study is to present biometrical data of the fetal lung measured in real-time sonography in mid-pregnancy. In 313 healthy fetuses of singleton pregnancies between the 15th and 30th week of gestation the fetal lung was measured in the horizontal, sagittal and frontal cross-sectional planes. In each plane the lung was measured in the following levels: clavicula, heart at the atrioventricular level (four chamber view) and diaphragm, as well as the lung length. During observation time all parameters showed a significant linear increase (r2 > 0.9; p < 0.001). Furthermore we found a high correlation between the same lung measurements collected in the different planes. The intraobserver variability was 3-8%. Such references of different planes could be helpful for differentiation of a small (hypoplasia) or a large lung (malformation).

[Doppler examination of the fetal left and right pulmonary artery. Relation to fetal position and gestational age: a methodological study]

A Methodical Study:

AIM OF THE STUDY

To analyse the feasibility of colour and spectral Doppler assessment of blood flow in the fetal right (RPA) and left (LPA) main pulmonary arteries in relation to fetal position and to gestational age.

STUDY DESIGN

The fetal position was a priori divided into 3 types, depending on whether the fetal heart was visualised apically (Type 1), from the right side (Type 2) or from the left side (Type 3). Three groups A (19-25 weeks gestation), B (26-32) and C (33-39) including 33 consecutive pregnancies each, were examined to document the fetal position as well as the rate of the successful Doppler examinations of the RPA and/or LPA.

RESULTS

The fetal position Type 2 was most common throughout gestation (in group A = 42%, B = 36%, C = 51%) followed by the type 3 and then type 1. The rate of successful Doppler records from the RPA and LPA depended on the fetal position: In Type 2 RPA in 98%; in Type 3, LPA in 100%; but the apical approach was not effective (< 40%). Depending on gestational age, the success rates for a Doppler examination of at least one vessel were high (> 85%), whereas successful examination of both vessels was unlikely (12%).

CONCLUSIONS

In the second half of pregnancy, independent of fetal position, Doppler examination of at least one pulmonary artery is successful in most cases, whereas the assessment of both vessels is rather difficult.

Prenatal diagnosis of a choledochal cyst: a case report and review of the literature

There are 16 reported cases of prenatally diagnosed choledochal cyst in the literature. We present a new case diagnosed at 29 weeks' gestation by routine ultrasound scanning. At 40 weeks' gestation, a male infant was born by spontaneous delivery. At 16 weeks of age, the patient underwent a laparotomy, which confirmed the diagnosis of a choledochal cyst. The cyst and the gallbladder were removed en bloc and reconstruction of the biliary tree was performed by formation of a retrocolic Roux-en-Y-hapatojejunostomy with an antireflux valve. Histological examination of the cyst showed a thickened fibrous tissue wall with necrotising areas and without epithelial lining. The patient's postoperative course was uneventful. Review of the literature shows that it is possible to make a presumptive prenatal diagnosis of this anomaly as early as 15 weeks' gestation. The differential diagnosis of a sonolucent lesion in the fetus should also include the rare choledochal cyst. Treatment of choice is the radical excision of the cyst with construction of a Roux-en-Y hepaticoenterostomy. Long-term results with this method are very good. Surgery may be instituted at the earliest possible opportunity before severe complications such as cholangitis, liver abscesses, cirrhosis, and malignant degeneration can occur.

Associated malformations and chromosomal defects in congenital diaphragmatic hernia

In order to determine the frequency of associated malformations and chromosomal defects in patients with congenital diaphragmatic hernia (CDH) our experiences with CDH during the last 8 years (1985-1993) were reviewed. During the study period, 33 fetuses (prenatal group) with CDH were examined at our level III ultrasound department. In the same period 11 neonates (postnatal group) were admitted to our pediatric surgical unit after postnatal diagnosis of a CDH. Those cases had not been suspicious for CDH during prenatal level I scan. In 24 (72.7%) of the cases with CDH seen prenatally, at least one or more extradiaphragmatic malformations could be detected. Most of them affected the cardiovascular, skeletal, genitourinary and nervous system. Six (18.1%) fetuses had chromosomal abnormalities, especially trisomy 18. In contrast to these findings just 4 of the 11 babies (36.3%) seen postnatally had associated malformations and all of them had a normal chromosome set. Survival rate of fetuses with CDH and associated anomalies (7.1%) was poor, in contrast to those with an isolated CDH (43.7%). Prenatal ultrasound investigations being suspect for CDH should encourage the clinician to make further diagnostical efforts. This includes detailed ultrasound examination and cytogenetic analysis. Associated malformations as well as chromosomal defects are often present in affected patients.