Antenatal sonographic detection of single umbilical artery.

The absence of one umbilical artery of single umbilical artery (SUA) is one of the most common congenital malformations in man. This vascular anomaly of the umbilical cord is frequently associated with other congenital malformations as well as some adverse perinatal events such as intrauterine growth retardation (IUGR), premature delivery, and increased perinatal mortality. Five cases of SUA detected prenatally by ultrasound are reported here in detail, including the first reported case in a twin gestation. None of the 5 affected infants had associated anomalies, but 2 cases of intrauterine growth retardation (IUGR) and 1 stillborn infant were noted in this series. An umbilical vein/umbilical artery ratio less than 2 was invariably found in all cases, making this observation another useful sonographic characteristic to use in the antenatal detection of SUA. Since the umbilical cord can be easily seen prenatally by ultrasound, and SUA is recognized as an important index for detecting congenital malformations, examination of the umbilical cord for the absence of one umbilical artery is an extremely valuable tool in prenatal diagnosis. The prenatal detection of SUA demands an extensive search for associated anomalies and a close surveillance of fetal well-being, since these fetuses have a high risk of fetal death or IUGR. Sonologists and sonographers should be aware of the possibility of SUA, especially in those cases associated with congenital malformations or IUGR.     

Fetal liver ultrasound measurements in isoimmunized pregnancies

Sixteen isoimmunized pregnancies at risk for erythroblastosis fetalis were managed by serial amniocenteses for bilirubin delta optical density at 450 nm (delta OD450). Before amniocentesis each fetus was evaluated ultrasonically and the fetal liver size, the abdominal circumference, and the umbilical vein diameter, in both the fetal liver and the umbilical cord, were measured. The ultrasonically determined fetal liver size, as well as its growth rate, was found to be greater than normal during the last two weeks before intervention (intrauterine transfusion or delivery) in all eight fetuses with severe hemolytic disease. The umbilical vein diameter in the fetal liver was above normal in only one fetus, whereas the abdominal circumference was increased in only three of the eight severely affected fetuses. These data suggest that serial fetal liver ultrasound measurements may be useful as an adjunct to amniotic fluid analysis to predict the severely affected fetus in need of prompt intervention (intrauterine transfusion or delivery).     

Hematologic evaluation of growth retarded fetus by cordocentesis

Fetal blood sampling by ultrasound-guided cordocentesis was performed in 22 IUGR fetuses in order to evaluate the fetal condition. All patients were referred to our hospital for further examination and management. In addition to hematological assessment we measured the velocity profiles of the umbilical artery with pulse-gated Doppler equipment. On the whole, pH and pO2 in the umbilical vein of IUGR fetuses were significantly lower and pCO2 higher, respectively, the corresponding values in controls. In particular, IUGR fetuses which had an etiology of maternal pre-eclampsia had fallen into hypoxemia. However, other laboratory values in IUGR did not differ from those of the controls except for the platelet count, which was low in the IUGR fetuses. Five fetuses with chromosomal abnormalities were found by analyzing the fetal blood. Since there are different etiologies inducing IUGR, fetus and umbilical artery velocimetry is not always predictive of the state of the IUGR fetus, hematological assessment is considered indispensable for further management.     

Pulsations of the umbilical vein: pathophysiologic aspects and fetal outcome

Continuous forward flow to the fetal heart in the umbilical vein is a normal Doppler finding. Altered fetal hemodynamics can cause a pulsatile flow pattern in the umbilical vein. Pulsations in the umbilical vein were diagnosed in 14 pregnancies complicated by fetal hydrops, cardiac malformations, arrhythmia or severe intrauterine growth retardation. To document the fetal outcome, the results were analysed retrospectively. Compared with a normal Doppler group (N = 56), a significantly higher rate of perinatal death (Alpha < 1%), (64% vs 1.75%) was diagnosed, when pulsations in the umbilical vein were present. The Apgar-score was significantly lower (4.5 vs 8.4) (p < 0.0002) in the group with pulsations in the umbilical vein. There was no significant difference of pH between the newborns of the two groups. Eight fetuses developed hydrops. Thirteen fetuses had increased reverse flow in the inferior vena cava. The vena cava of the acardiac fetus could not be identified. The knowledge of the poor outcome and the pathophysiologic relationships of fetal hemodynamics may be useful in clinical management. Therefore Doppler examination of the umbilical vein should be performed in high-risk pregnancies.     

Obstetric management of fetal growth retardation

Intrauterine growth restriction (IGUR) can have different etiologies, but placental insufficiency is the clinically most relevant. Fetuses with IUGR have a significantly higher morbidity and mortality than normally grown fetuses of the same gestational age. It is important to distinguish a growth restricted fetus from a normal, small fetus and from a fetus being small because of a disease, e.g., an aneuploidy. This differentiation requires the knowledge of the gestational age and the use of multiple imaging modalities. Serial assessments of fetal growth by ultrasound are necessary to recognize declining growth. Doppler sonography can detect changes in the uteroplacentar and the fetal perfusion. Blood vessels of clinical relevance are the uterine arteries, the umbilical artery, the middle cerebral artery and the ductus venosus. When no fetal anomalies can be detected, fetal growth is parallel to the percentiles and Doppler sonography measurements are normal, IUGR is unlikely. In most IUGR fetuses, a typical sequence of circulatory changes and ultrasound findings can be observed. As there is no evidence-based treatment option for IUGR until now, obstetric management consists in defining the optimal time of delivery. This means weighing the risks of prematurity against the risks of a potentially hostile intrauterine environment.     

Variables that affect the middle cerebral artery peak systolic velocity in fetuses with anemia and intrauterine growth restriction

We have previously reported that the fetal middle cerebral artery (MCA) peak systolic velocity (PSV) increases in anemic fetuses and in fetuses with intrauterine growth restriction (IUGR). We hypothesized that the pathophysiology for the increased MCA PSV is different in anemic and IUGR fetuses. Thus the aim of this study was to determine the factor(s) among fetal umbilical vein blood pH, Po2, Pco2, and hemoglobin that might affect the MCA PSV in fetuses with anemia and IUGR. This study included two groups of fetuses. The first group included fetuses at risk for anemia because of red cell alloimmunization, whereas the second group included IUGR fetuses. For both groups of fetuses, we determined hemoglobin, umbilical vein blood gases -- at cordocentesis in anemic fetuses and immediately after cesarean delivery in IUGR fetuses -- and MCA PSV before cordocentesis, or before delivery. The relationship between MCA PSV and the hemoglobin, Po2, Pco2, and pH values for the anemic and the IUGR fetuses were assessed by regression analysis using multiples of the mean. There were 14 fetuses in the first group and 22 fetuses in the second group. In the first group, the only parameter that was related to MCA PSV was the fetal hemoglobin (R2 = 0.34; p < 0.05); in fetuses with IUGR, the Pco2 (R2 = 0.36; p < 0.01) and the PO2 (R2 = 0.30; p < 0.01) correlated well with the MCA PSV, whereas no relationship was found between the MCA PSV and the hemoglobin. The data indicate that the mechanism of high MCA PSV is different in anemic and nonanemic IUGR fetuses, and suggest that the process of cerebral autoregulation is present in the preterm IUGR fetus.     

Assessment of blood flow in the middle cerebral artery and the umbilical artery in fetuses with umbilical venous pulsations

OBJECTIVES: Umbilical venous pulsation is an important sign of hemodynamic compromise, especially during fetal heart failure and asphyxia. DESIGN: The aim of this study was to determine of the blow flow in the middle cerebral artery and the umbilical artery in fetuses with umbilical venous pulsations. MATERIALS AND METHODS: The investigation included 18 fetuses with signs of the intrauterine growth restriction and umbilical venous pulsations after 28th weeks of gestation. We evaluated cerebral-placental ratio (CPR) and pulsation index (PI) in the middle cerebral artery (MCA) and the umbilical artery (UA). RESULTS: We observed brain sparring effect in all cases of analyzing fetuses. There were 77,8% of abnormal flow pattern in umbilical artery. 13 fetuses had a single pulsation pattern in umbilical vein and another 5 had double pulsation pattern. CONCLUSIONS: The coexistence of umbilical vein pulsation and abnormal flow pattern in umbilical artery is closely related to increased perinatal mortality.     

Doppler assessment of the fetal asphyxia in pregnancies complicated by gestational hypertension and intrauterine growth retardation

OBJECTIVES: Gestational hypertension is associated with a high morbidity for both mother and fetus. Doppler ultrasound has allowed the fetal circulation to be examined. Now it is possible to monitor the response of the fetal circulation to hypoxia. DESIGN: The aim of this study was to determine flow patterns in fetal circulation from pregnancies complicated by gestational hypertension and intrauterine growth restriction. MATERIALS AND METHODS: The investigation included 23 fetuses with signs of the gestational hypertension and intrauterine growth restriction. We evaluated cerebral-placental ratio (CPR) and pulsation index (PI) in the middle cerebral artery (MCA) and the umbilical artery (UA). We also evaluated flows in umbilical vein. RESULTS: We observed abnormal flow pattern in all cases of analyzing fetuses. The most common abnormal flow was vein pulsation (48%). CONCLUSIONS: All analyzing fetuses shown signs of the hypoxia. Present of the umbilical vein pulsation or decompensate of the brain sparing effect is closely related o increased perinatal mortality.     

The fetal cardiovascular response to antenatal steroids in severe early-onset intrauterine growth restriction

OBJECTIVE: Our aim was to study the hemodynamic effects of betamethasone on fetuses with intrauterine growth restriction (IUGR) with absent or reversed end-diastolic (ARED) umbilical artery flow. STUDY DESIGN: Color/pulsed Doppler waveforms were obtained before and after intramuscular injections of betamethasone in 19 consecutive fetuses with IUGR/ARED and 6 control fetuses. Peak velocities and pulsatility index (PI) values were obtained from the umbilical (UA) and middle cerebral (MCA) arteries and intrahepatic umbilical vein (UV). RESULTS: Ten ARED fetuses developed transient positive umbilical end-diastolic flow after steroids, whereas nine fetuses showed persistent ARED. The persistent ARED subgroup demonstrated increased UA and UV peak velocities after steroids, which may indicate fetal hypertension. Fetal death (n=2) and severe acidosis (n=2) were confined to the subgroup with persistent ARED. CONCLUSION: Preterm IUGR/ARED fetuses exhibit divergent cardiovascular responses to prenatal steroids. Intensive Doppler-based fetal monitoring may identify a subset of fetuses prone to decompensation after maternal steroid administration.     

Three-dimensional color power imaging of the fetal hepatic circulation

OBJECTIVE: The purpose of this study was to describe the use of three-dimensional power Doppler ultrasonography to identify vascular congenital anomalies of fetal portosystemic and umbilical venous systems. STUDY DESIGN: In a prospective study, the hepatic and umbilical venous systems were examined in 390 fetuses with two-dimensional ultrasonography, color, and spectral Doppler imaging. Fetuses suspected to have anomalies of the portal system and ductus venosus were additionally examined with three-dimensional power Doppler ultrasonography. RESULTS: Vascular anomalies were identified in 8 fetuses (absent ductus venosus, n=4; direct connection between the umbilical vein and the right atrium, n=2; and direct connection between the umbilical vein and the inferior vena cava, n=2) out of the 310 in which the venous system could be adequately imaged (prevalence=2.6%). Three-dimensional power Doppler imaging showed the course of the umbilical vein, its relationship to the portosystemic circulation, and whether a ductus venosus was present. CONCLUSION: Three-dimensional power Doppler ultrasonography can be used to image normal fetal hepatic and portal circulation, as well as identify anomalies of the fetal portosystemic and umbilical venous systems.     

Cerebral venous blood flow in growth restricted fetuses with an abnormal blood flow in the umbilical artery before 32 weeks of gestation

Objective

To evaluate the brain venous circulation in fetuses with severe intrauterine growth restriction (IUGR) before 32 weeks of gestation.

Study design

Fifty fetuses with severe IUGR diagnosed between 27 and 32 weeks of gestation and 50 appropriate-for-gestational age (AGA) fetuses matched by gestational age were evaluated. IUGR fetuses were classified according to their hemodynamic deterioration pattern in relation to the Doppler examination of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV). The fetal venous brain blood flow was evaluated in the vein of Galen (VG), superior sagittal (SS), straight and transverse venous sinuses.

Results

Only the transverse sinus (TS) showed a significant reduction in the pulsatility index (PI) values in IUGR fetuses. All other veins showed similar PI values between IUGR and AGA fetuses. All cerebral veins of IUGR fetuses showed significantly increased maximum and mean velocities. All these findings did not change in relation to the hemodynamic IUGR deterioration. In nearly all normal and all IUGR fetuses, a pulsatile blood flow pattern was observed in the straight and transverse sinuses, whereas an increased pulsatile pattern in the VG and in the SS was noted in IUGR fetuses.

Conclusion

Brain venous blood flow in IUGR fetuses shows an increment in the maximum and mean velocities of all veins and a reduction in the PI in the transverse sinus.     

Glucose gradients of maternal vein-umbilical vein and umbilical vein-umbilical artery in normally grown and growth-retarded fetuses.

The present study was designed to investigate the roles of maternal-fetal glucose transport and fetal glucose utilization in the regulation of fetal growth. Maternal venous blood, umbilical arterial and venous blood were sampled simultaneously in 60 full-term appropriate-for gestational age (AGA) fetuses and 48 small-for-gestational-age (SGA) fetuses. The cases were divided into four groups: group 1 consisted of 35 AGA fetuses, group 2 consisted of 25 AGA fetuses, group 3 consisted of 25 SGA fetuses, and group 4 consisted of 22 SGA fetuses. The mothers of group 1 and 3 were given 2.5% glucose in 0.9% normal saline and those of groups 2 and 4 by cesarean section received normal saline or Ringer's lactate at least one hour prior to delivery of the fetus SGA fetuses were found to have hypoglycaemia of umbilical venous blood, increased (maternal vein-umbilical vein) MV-UV and decreased UV-UA (umbilical vein-umbilical artery) glucose gradients, all of which disappeared after maternal glucose supplementation. However, hypoinsulinemia and lower insulin/glucose ratio in SGA fetuses persisted either with or without maternal parenteral glucose infusion. Increased MV-UV and decreased UV-UA glucose gradients suggests placental dysfunction and poor glucose utilization in SGA fetuses. The lower fetal insulin/glucose ratio may imply pancreatic dysfunction in SGA fetuses, which did not respond to glucose challenge from the maternal side. It seems that in SGA fetuses, placental dysfunction interferes with maternal-fetal transfer with resulting fetal hypoglycemia; on the other hand, pancreatic dysfunction leads to poor glucose utilization and retarded intrauterine growth. However, the mechanism that primarily accounts for pancreatic dysfunction in these fetuses remains to be resolved.     

The transitional phase of ductus venosus reversed flow in severely premature IUGR fetuses

The guiding hypothesis for this work is that in severe intrauterine growth-restricted (IUGR) fetuses, the time from ductus venosus (DV) reversed flow (RF) appearance to intrauterine fetal demise (IUFD) or nonreassuring fetal testing is variable. As such, there must be a transitional phase between the presence of end-diastolic forward flow (FF) and absent or reversed end-diastolic flow (A/REDF). Ductus venosus Doppler was serially studied in 19 IUGR fetuses (estimated fetal weight < 10th percentile and umbilical artery pulsatility index > 95th percentile) from diagnosis until demise or delivery occurring for nonreassuring fetal testing. Ductus venosus waveforms were assessed qualitatively: forward flow versus absent or reversed flow in diastole. Two sets of at least 30 consecutive ductus venosus waveforms were obtained at each examination. If the waveforms differed between the two sets, they were defined as alternating. Cord arterial pH and base excess (BE) were obtained at birth. In 14 cases, DVRF occurred intermittently between periods of FF during the same clinical visit. Intermittent DVRF was present from 2 to 57 days (median, 13 days) and became continuous from 1 to 23 days (median, 7 days) before the occurrence of delivery for nonreassuring fetal testing or fetal demise. One fetus had an abnormal arterial pH (< 7.0) and one had an abnormal BE (< -12). These data show that (1) there is a transitional phase in which DV alternates FF and A/RF before RF becomes persistent; (2) the time from the appearance of DVRF to delivery or IUFD is variable, and (3) not all very preterm IUGR fetuses with continuous DVRF are acidemic. Because of these findings, the decision of delivery regarding early severe IUGR fetuses should be individualized, and the DVRF Doppler information has to be integrated with other antenatal fetal parameters.     

Can we predict 22q11 status of fetuses with tetralogy of Fallot?

OBJECTIVE: To determine if chromosome 22q11 deletion status can be predicted in fetuses with tetralogy of Fallot as regards additional phenotypic anomalies. METHODS: One hundred and fifty-one consecutive fetuses with tetralogy of Fallot without or with pulmonary atresia were screened for 22q11 deletion. Additional echographic features [increased nuchal translucency (NT), intrauterine growth retardation (IUGR), polyhydramnios, extracardiac malformations, pulmonary arteries abnormalities] were noted. RESULTS: Twenty-five fetuses had a 22q11 deletion (16.6%). Increased NT, polyhydramnios and IUGR were more frequent in fetuses with 22q11 deletion as well as pulmonary arterial abnormalities. When these different features were present in the same fetus with tetralogy of Fallot, 22q11 deletion can be predicted with a sensitivity of 88%. CONCLUSION: Simple echographic features can help to predict 22q11 status in fetuses with tetralogy of Fallot. This may improve the efficiency of prenatal screening for this defect.     

Single umbilical artery: prenatal findings

In 450 patients with pregnancy at high risk for fetal malformation and/or intrauterine growth retardation, the umbilical cord was investigated sonographically for the presence of a single umbilical artery. A single umbilical artery was diagnosed in four fetuses between 23 and 33 weeks of gestation and suspected in two. Three cases were overlooked at sonography. All seven surviving fetuses had growth retardation at delivery and four also showed severe malformations. Whenever a single umbilical artery is found at sonography, further work-up is required to rule out associated anomalies, intrauterine growth retardation, or chromosomal abnormality.     

Agenesis of the ductus venosus that is associated with extrahepatic umbilical vein drainage: prenatal features and clinical outcome

OBJECTIVE: We sought to study the clinical and ultrasonographic findings and outcomes of fetuses with ductus venosus agenesis as the result of extrahepatic umbilical vein drainage. STUDY DESIGN: This was an observational study of 12 fetuses who were diagnosed with these anomalies between 1995 and 2001. RESULTS: The umbilical vein drained either directly into the right atrium (n = 7 fetuses), the inferior vena cava (n = 3 fetuses), or the iliac vein (n = 2 fetuses). Combined cardiac output (n = 8 fetuses) was nearly 2-fold increased to 891 +/- 210 mL/kg per minute. Other relevant findings were (1) considerable umbilical vein enlargement (12/12 cases; range, 8-13 mm) with an accelerated (peak, 0.53 +/- 0.1 m/s), (2) pulsatile Doppler flow pattern within its intra-abdominal course, (3) cardiomegaly (12/12 fetuses), (4) secundum atrial septal defects (5/12 fetuses), (5) extracardiac anomalies (5/12 fetuses), (6) polyhydramnios (4/12 fetuses), and (7) progressive heart failure (3/12 fetuses). Two fetuses died: 1 death was unexplained at 29 weeks of gestation; the other death from hydrops occurred after delivery at 32 weeks of gestation. So far, none of the survivors have had other long-term sequelae that were related to ductus venosus agenesis. CONCLUSION: Careful assessment of the umbilical venous return and the ductus venosus should be part of the routine evaluation of every fetus with heart failure and polyhydramnios.     

The effect of a maternal infusion of amino acids on umbilical uptake in pregnancies complicated by intrauterine growth restriction

OBJECTIVE: To establish whether, in human pregnancies complicated by intrauterine growth restriction (IUGR), the maternal intravenous infusion of amino acids can increase fetal amino acid concentrations and umbilical uptake. STUDY DESIGN: Before elective cesarean delivery, a solution of amino acids was infused into a maternal vein in 8 patients with pregnancies complicated by IUGR (experimental group). At cesarean delivery, maternal, umbilical venous, and arterial blood samples were obtained. Ten comparable IUGR pregnancies were compared with those in the experimental group. RESULTS: In the experimental group, all maternal amino acid concentrations were increased significantly. In the umbilical vein, valine, methionine, isoleucine, leucine, phenylalanine, arginine, serine, glycine, and proline concentrations were elevated. Umbilical venoarterial differences of amino acid per mole of oxygen for leucine, isoleucine, methionine, arginine, glycine, serine, and proline were elevated but not for lysine, histidine, threonine, valine, and phenylalanine. CONCLUSION: In pregnancies complicated by IUGR, increasing the maternal concentration of amino acids leads to an increased umbilical uptake of some of the amino acids to the fetus. There was no evidence of a change in the uptake of 3 essential amino acids: lysine, histidine, and threonine.     

Screening and timing for the delivery of fetuses with intrauterine growth restriction of vascular origin

The prenatal management of fetuses with intrauterine growth restriction (IUGR) has been a matter of perpetual evolving in obstetrics and has been the topic of numerous studies. The management of IUGR fetuses is currently available in tertiary centres using fetal heart monitoring, short term variability, or doppler investigation of the umbilical artery, ductus venosus and middle cerebral artery. The aim of the prenatal management is to detect anomalies that may predict severe fetal hypoxemia. On the other hand, any efforts should focus on the possibility to delay the time for delivery as gestational age at delivery together with birth weight appear to be essential parameters of the postnatal outcome.     

Doppler assessment of the fetal venous system

This article describes the achievements in Doppler measurements of the fetal venous circulation with emphasis on the clinical impact of these techniques. In rhesus isoimmunization, fetal venous flow assessment gives useful information on the fetal haematologic condition and on the impact of blood transfusion. In first trimester fetuses, Doppler evaluation of the ductus venosus and umbilical vein could attribute to the detection of cardiac defects and/or chromosomal abnormalities. The inferior vena cava flow velocity waveform could be studied in cases of fetal arrhythmias to be able to diagnose the type of fetal heart rhythm disturbances. One of the more important applications of venous Doppler assessment is its use in the evaluation of the intrauterine growth retarded fetus, who is suffering from placental insufficiency. Decrease of the late diastolic flow component in the ductus venosus waveform and the presence of umbilical venous pulsations are distinct alterations, which have been detected before cardiotocogram deterioration occurs. The clinical possibilities of venous Doppler measurements are limited, and the use of the techniques requires intensive training.     

Association of severe placental insufficiency and systemic venous pressure rise in the fetus with increased neonatal cardiac troponin T levels

OBJECTIVE: The aim of this study was to test the hypothesis that severe placental insufficiency and a rise in fetal systemic venous pressure are associated with fetal myocardial cell damage, which in turn leads to increased neonatal troponin T levels. STUDY DESIGN: Sixty-six neonates born after uncomplicated pregnancy and delivery were included in the control group. Study groups 1 and 2 consisted of 32 and 5 neonates, respectively, born to women with hypertensive disorder. In study group 1 the fetal intra-abdominal portion of the umbilical vein showed normal nonpulsatile blood flow pattern in every case. In study group 2 all the fetuses had atrial pulsations in the intraabdominal umbilical vein. After delivery blood samples were collected from the umbilical arteries, and cardiac troponin T concentrations were measured with commercially available enzyme-linked immunosorbent assay kits. A clinically significant troponin T level was set at >/=0.10 ng/mL. RESULTS: In study group 1 the maternal main uterine arterial blood flow pattern was normal in 30 cases and abnormal in 2 cases. Umbilical artery blood velocity waveforms were normal in 26 fetuses, 4 fetuses had a decreased diastolic blood flow, 1 fetus had an absent diastolic blood flow pattern, and 1 fetus had a retrograde diastolic blood flow pattern. In study group 2 maternal uterine arterial Doppler findings were abnormal in every case, and all the fetuses had retrograde diastolic blood flow pattern in the umbilical artery. Neonatal troponin T levels were <0.10 ng/mL in the control group (0-0.14 ng/mL) and in study group 1 (0-0.16 ng/mL), except for 1 case in each group. Every neonate in study group 2 had a troponin T level >0.10 ng/mL, with the range from 0.11 to 0.35 ng/mL. In study group 2 troponin T concentrations were significantly higher (P <.0001) than in either the control group or study group 1. CONCLUSION: Neonatal troponin T levels are not clinically significantly increased in normal pregnancies and in pregnancies complicated by maternal hypertensive disorder but with normal fetal umbilical venous return. Neonatal troponin T concentrations are significantly increased in the presence of abnormal umbilical venous return, which indicates myocardial cell damage.