Evaluation of fetal heart anatomy at the end of the first trimester and the beginning of the mid-trimester

OBJECTIVE: To evaluate fetal heart anatomy in the late first and in the early second trimester. MATERIALS AND METHODS: The study included 75 fetuses between 11 and 19 weeks' gestation. Exams were performed using transabdominal or transvaginal probes. RESULTS: The proportion of cases successfully visualized to all cases in particular week of pregnancy was following: 11 week--0/1 (0%), 12--1/1 (100%), 13 week--1/1 (100%), 14--18/23 (79%), 15--6/9 (67%), 16--23/27 (86%), 17--4/5 (80%), 18--6/6 (100%), 19--2/2 (100%). In 11 weeks' gestation two ventricles and two atrias could be imaged. Anatomy was seen from 12 weeks' gestation with transvaginal and from 13 weeks' gestation with transabdominal transducers. Two tricuspid regurgitations were detected. The interventricular septum was the most difficult structure to visualize in all cases. The grey scale alone was not sufficient for accurate examination of the heart and it was necessary to use colour Doppler to confirm normal forward flow to both ventricles and to identify outflow tracts. CONCLUSIONS: 1. Successful visualization of the heart in early pregnancy is possible from 12 weeks' gestation with transvaginal and from 13 weeks' gestation with transabdominal probe. 2. Fetal echocardiography between first and second trimester should lead to better understanding of fetal hemodynamics in normal and abnormal fetuses and help to introduce new therapeutic treatment in some cases.     

Biometry of the fetal heart between 10 and 17 weeks of gestation

OBJECTIVES: Assessment of the dimensions of the cardiac chambers and the great arteries in the human fetus may be helpful in the prenatal diagnosis of congenital heart disease. The purpose of this prospective cross-sectional study was to compile normative data in fetal cardiac measurements in early pregnancy. The structure of the fetal heart was examined in 136 normal singleton fetuses between 10 and 17 weeks of gestation. METHODS: The transversal heart diameter, both ventricular dimensions, interventricular septal thickness, heart area, heart circumference, thoracic diameter, thoracic circumference and thoracic area were measured in the four-chamber view during diastole. Diameters of the pulmonary trunk and ascending aorta were obtained in the short axis and long axis view during systole. Ultrasound examinations were performed with a 5.0-MHz transvaginal and/or transabdominal phased-array sector scanner. RESULTS: The four-chamber view and the cross-over of the pulmonary artery and the aorta were adequately visualized in 44% of the fetuses at 10 weeks of gestation, in 75% at 11 weeks of gestation, in 93% at 12 weeks of gestation and in 100% of the fetuses at 13-17 weeks of gestation. Before 14 weeks of gestation transvaginal sonography was superior to the transabdominal sonography in visualization of the fetal heart and great arteries. After 14 weeks of gestation transabdominal sonography accurately demonstrated the structure of the fetal heart. The ratio of right and left ventricle (RV/LV) and the ratio of the pulmonary trunk and aorta (PT/AO) were constant during this period of gestation (approximately 1.00 and 1. 10, respectively). The ratio of the cardiac and thoracic area showed only a slight increase with advancing gestational age, but with significant correlation. The fetal heart rate showed a slow decrease from 167 to 150 bpm in this period of gestation. The transversal heart diameter, both ventricular dimensions, interventricular septal thickness, heart area, cardiothoracic diameter ratio, aortic diameter and the pulmonary trunk diameter showed a highly significant linear correlation to the gestational age and the biparietal diameter. CONCLUSION: The advancing quality of ultrasound images allows fetal echocardiography in the first and early second trimester. Our normative data could be the basis of studying the development of cardiac structures in congenital heart disease and it might be helpful in the detection of some congenital heart defects in early pregnancy.     

Two-dimensional echocardiographic assessment of normal fetal cardiac anatomy

The fetal heart is visualized routinely during the antepartum ultrasound examination. Because of the advent of high-resolution, real-time ultrasound instruments, details of fetal cardiac anatomy can now be defined. Fifty consecutive fetuses were examined in utero to assess the ability of two-dimensional echocardiography to define intracardiac anatomy at various gestational ages. A complete examination required at least three standard echocardiographic views of the heart: four-chamber, short-axis and long-axis views. In 30 of the 50 fetuses studied (60%) only one examination was necessary to obtain this information. Ten patients had a second examination later in gestation that complemented the findings of their first study. In all but two fetuses, detection of all four cardiac chambers and at least one semilunar valve was possible. Mitral-semilunar valve continuity was detected in all. The quality of echocardiographic imaging was enhanced by the fetal occiput posterior position (three views obtained in 83% of the fetuses studied). Breech position did not affect imaging quality. Prior to 30 weeks of gestation, fetal movement hampered analysis of fetal cardiac anatomy in some patients.     

Cardiac compliance in fetuses of diabetic women.

OBJECTIVE: To examine possible changes in cardiac function in fetuses of pregestational diabetic mothers. METHODS: We conducted a prospective longitudinal study of 31 women whose pregnancies were between 22 weeks' gestation and term, and who had pregestational diabetes. All diabetic women included in the study had glycosylated hemoglobin lower than 6.5%. All patients included in the study had an early ultrasound confirming gestational age. Doppler studies of the blood flow through the mitral and tricuspid valves were done every 4 weeks using a pulsed-wave Doppler ultrasound device with a 3.5- or 5-MHz transducer. The following indices were calculated from the flow velocity waveforms: the peak velocity during the rapid ventricular filling (E wave) and during the atrial systole (A wave), and the ratio between these velocities (E/A ratio); and the velocity time integral of the atrioventricular blood flow (this integral correlates with volume flow). A comparison between the Doppler indices obtained in fetuses of diabetic women and of normal women was made by using the Mann-Whitney test. RESULTS: Each patient had four to five fetal echocardiographic examinations at 22, 26, 30, 34, and 38 weeks' gestation. The E/A ratio of the mitral and tricuspid valves did not increase in fetuses of diabetic women during the third trimester and was significantly higher in fetuses of nondiabetic women compared with fetuses of diabetic women at 34 and 38 weeks' gestation. The velocity time integral of the mitral and tricuspid valves multiplied by heart rate was higher, but not significantly, in fetuses of nondiabetic women compared with fetuses of diabetic women at 34 and 38 weeks' gestation. The E-wave of the mitral and tricuspid valves increased in both groups throughout gestation. The A-wave of the mitral and tricuspid valves increased only in fetuses of diabetic women throughout the third trimester and was significantly higher at 34 and 38 weeks' gestation compared with fetuses of nondiabetic women. CONCLUSION: Differences in atrioventricular blood flow patterns between fetuses of diabetic women and normal fetuses do not necessarily result from differences in cardiac compliance.     

Four-dimensional ultrasonography of the fetal heart with spatiotemporal image correlation

OBJECTIVE: This study was undertaken to describe a new technique for the examination of the fetal heart using four-dimensional ultrasonography with spatiotemporal image correlation (STIC). STUDY DESIGN: Volume data sets of the fetal heart were acquired with a new cardiac gating technique (STIC), which uses automated transverse and longitudinal sweeps of the anterior chest wall. These volumes were obtained from 69 fetuses: 35 normal, 16 with congenital anomalies not affecting the cardiovascular system, and 18 with cardiac abnormalities. Dynamic multiplanar slicing and surface rendering of cardiac structures were performed. To illustrate the STIC technique, two representative volumes from a normal fetus were compared with volumes obtained from fetuses with the following congenital heart anomalies: atrioventricular septal defect, tricuspid stenosis, tricuspid atresia, and interrupted inferior vena cava with abnormal venous drainage. RESULTS: Volume datasets obtained with a transverse sweep were utilized to demonstrate the cardiac chambers, moderator band, interatrial and interventricular septae, atrioventricular valves, pulmonary veins, and outflow tracts. With the use of a reference dot to navigate the four-chamber view, intracardiac structures could be simultaneously studied in three orthogonal planes. The same volume dataset was used for surface rendering of the atrioventricular valves. The aortic and ductal arches were best visualized when the original plane of acquisition was sagittal. Volumes could be interactively manipulated to simultaneously visualize both outflow tracts, in addition to the aortic and ductal arches. Novel views of specific structures were generated. For example, the location and extent of a ventricular septal defect was imaged in a sagittal view of the interventricular septum. Furthermore, surface-rendered images of the atrioventricular valves were employed to distinguish between normal and pathologic conditions. Representative video clips were posted on the Journal's Web site to demonstrate the diagnostic capabilities of this new technique. CONCLUSION: Dynamic multiplanar slicing and surface rendering of the fetal heart are feasible with STIC technology. One good quality volume dataset, obtained from a transverse sweep, can be used to examine the four-chamber view and the outflow tracts. This novel method may assist in the evaluation of fetal cardiac anatomy.     

Two-dimensional and M mode echocardiography in the human fetus

One hundred unselected pregnant women underwent M mode and two-dimensional fetal echocardiographic studies between 14 and 43 weeks' gestation. The following cross-sectional views were obtained: high parasternal short axis, parasternal long axis, four chamber view, and an extended long axis to assess the aorta. These views successfully identified great vessel orientation and size (90%), atrial and ventricular size and function (90%), presence of atrioventricular valves (92%) and semilunar valves (75%), and presence and continuity of ventricular and atrial septa (91%) and the aortic arch (68%). Factors that limited visualization were persistent unfavorable lie, maternal obesity, and oligohydramnios. Disturbances in cardiac rhythm were the prevalent abnormal findings (16%). In addition, several anatomic defects were detected in utero and confirmed at autopsy. These included a biventricular cardiomyopathy, atrial septal defect, pericardial effusion, and hypoplastic heart. The potential applications of our ability to detail human fetal cardiac anatomy and dimensions are discussed.     

The three-vessel and tracheal view of the fetal heart: an in utero sonographic evaluation

OBJECTIVES: To establish a nomogram for fetal cardiac three-vessel view diameter changes during gestation. METHODS: The study is a prospective cross-sectional evaluation of 338 male and female fetuses between 14 and 38 weeks of normal singleton pregnancies. Measurements of fetal pulmonary artery, aorta and superior vena cava diameters, performed on a transverse view of the upper mediastinum were conducted using transvaginal ultrasonography between 14 to 18 weeks and transabdominal after 19 weeks' gestation. RESULTS: Adequate measurements of the three cardiac vessels were obtained in 338 fetuses. The regression equations for vessel diameters modeled as function of gestational age were pulmonary artery diameter (mm) = -2.275 + 0.273 x gestational age (week), aorta diameter (mm) = -1.77 + 0.227 x gestational age (week), and SVC diameter (mm) = -0.98 + 0.142 x gestational age (week). The correlation coefficients between gestational age and the diameter of the vessels were, r = 0.93, r = 0.93 and r = 0.86 for pulmonary artery, aorta and SVC respectively (all found to be highly statistically significant, p < 0.0001). The normal mean and 90% prediction limits were defined. CONCLUSION: Our data present the normal range of fetal heart three-vessel diameters during gestation. They may allow intrauterine assessment of their development and an adjunct in the detection and evaluation of great vessel pathology.     

Accuracy and limitations of transabdominal fetal echocardiography at 12-15 weeks of gestation in a population at high risk for congenital heart disease

Objective Evaluation of transabdominal fetal echocardiography at 12–15 weeks of gestation.
Design Retrospective analysis.
Setting Tertiary fetal cardiology unit.
Sample Two hundred twenty-nine consecutive fetuses imaged at 12–15 weeks of gestation over a 45-month period.
Methods Retrospective analysis of echocardiography and autopsy reports.
Main outcome measures Accuracy of early echocardiography for the detection of abnormalities of the cardiac connections.
Results Diagnostic images were obtained in 226/229 fetuses (98.7%). Abnormalities of the cardiac connections were detected in 13 fetuses (5.7%) on the initial scan. Where information was available (   n = 11  ), the echocardiographic findings were confirmed at autopsy or postnatally. In two of the 13 cases of congenital heart disease, repeat echocardiography was necessary to provide additional cardiological information. Of the 213 cases in whom a normal initial report was issued, four (1.7%) had congenital heart disease diagnosed later in pregnancy (   n = 3  ) or postnatally (   n = 1  ). Three of these fetuses had haemodynamically insignificant ventricular septal defects and one developed a dilated cardiomyopathy later in gestation.
Conclusions Transabdominal fetal echocardiography can be performed at 12–15 weeks of gestation permitting accurate early detection of major congenital heart defects in a high risk population. Some forms of congenital heart disease, usually minor, may not be detectable at such an early stage.     

Normal reference ranges from 11 to 41 weeks' gestation of fetal left modified myocardial performance index by conventional Doppler with the use of stringent criteria for delimitation of the time periods

Objective: To establish normal reference intervals of the fetal left modified myocardial performance index (MPI) with the use of stringent criteria for delimitation of the time periods. Study Design: A cohort of consecutive singleton fetuses was created including at least 20 fetuses for each completed week of gestation between 11 and 41 weeks. The isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT), and ejection time (ET) were calculated using the clicks of the mitral and aortic valves as landmarks, and the MPI was calculated as follows: (ICT + IRT)/ET. Normal reference ranges for the MPI and its individual components were constructed by means of regression analysis of the mean and standard deviation against gestational age (GA). Results: A total of 730 fetuses were included. After a natural logarithmic transformation, a third degree cubic polynomial model (log(e) mean MPI = 0.0477 × GA - 0.002565 × GA(2) + 0.000043 × GA(3) -1.22, with GA measured in weeks) was selected to fit our data. There was a progressive increase in the mean MPI from 11 weeks (mean, 0.39; 95th centile, 0.51) to 41 weeks (mean, 0.55; 95th centile, 0.78) of gestation. While the mean ICT and IRT values increased with GA from 25 to 32 ms and from 39 to 51 ms, respectively, the ET showed an initial increase until 30 weeks and a progressive decrease thereafter. Conclusion: Normative references of left modified MPI from 11 to 41 weeks of gestation are provided, which could be useful in the assessment of cardiac function in fetuses.     

The evaluation of cardiac biometry in major cardiac defects detected in early pregnancy

The objective was to evaluate early cardiac biometry in fetuses with structural cardiac defects between 10 and 17 weeks of gestation using our normative data about fetal heart biometry. A retrospective case series, patients were selected from all cases with congenital heart disease diagnosed between 10 and 17 weeks of gestation in our prenatal unit between 1999 and 2000. A schematic sonographic examination, including nuchal translucency (NT) thickness measurements, was performed and was followed by fetal Doppler echocardiography. The transversal heart diameter, both ventricular dimensions, heart area, heart circumference, thoracic diameter, thoracic circumference, thoracic area, pulmonary trunk diameter and aortic diameter were measured and the cardiothoracic ratios were calculated. Doppler evaluation of the umbilical arteries, ductus venosus and umbilical vein was performed. Fetal karyotyping was obtained by amniocentesis or chorionic villous sampling. During the study period, 31 cases of congenital heart disease between 10 and 17 weeks of gestation were diagnosed. Of these, two fetuses presented with ectopia cordis and six with insufficient cardiac biometric measurements. In the remaining 23 fetuses, different complex abnormalities with a high rate of chromosomal abnormalities (91%) were present. Fetal heart biometry was normal in 22% and abnormal in 78%. NT thickness measurements were performed before 14 weeks of gestation and ten of 12 fetuses (83%) presented with an increased NT. Both fetuses with normal NT showed an abnormal fetal heart biometry. Venous Doppler evaluation was performed in 22 cases and 12 fetuses (55%) demonstrated an abnormal venous Doppler. There were ten fetuses (45%) with normal venous Doppler; in seven of these cases, fetal heart biometry was partly abnormal. This study shows the feasibility of first and early second trimesters' fetal echocardiography and the applicability of cardiac biometry in these instances. In this context, early fetal heart biometry and NT thickness measurements may be complementary methods for the prenatal diagnosis of some major congenital heart defects. In early pregnancy, some cardiac defects like tricuspid valve dysplasia, coarctation of the aorta, aortic stenosis, tetralogy of Fallot or pulmonary stenosis may already show similar changes in the relation of the diameters of the fetal heart and great arteries, as seen in the second trimester. Therefore, evaluating the different cardiac ratios may have a high diagnostic value in early pregnancy.     

Ultrasonographic assessment of gestational age with the distal femoral and proximal tibial ossification centers in the third trimester

A prospective sonographic evaluation of the distal femoral and proximal tibial epiphyseal ossification centers in 228 normal pregnant women was carried out from 28 to 40 weeks' gestation. The mean gestational age at which the distal femoral epiphysis and proximal tibial epiphysis were imaged was 34 and 38 weeks, respectively. The distal femoral epiphysis was not identifiable before 28 weeks but was observed in 72% of fetuses at 33 weeks and in 94% of fetuses at 34 weeks' gestation. The presence of a distal femoral epiphysis measuring 1 or 2 mm was associated with a gestational age of greater than 33 weeks in 87.0% of fetuses, whereas a distal femoral epiphysis measuring greater than or equal to 3 mm was associated with a gestational age greater than 37 weeks in 85% of fetuses. The proximal tibial epiphysis, which was absent before 34 weeks' gestation, was observed in 56% of fetuses at 36 weeks, in 80% of fetuses at 37 weeks, and in 100% of fetuses at 39 weeks of gestation. The presence of a proximal tibial epiphysis of 1 or 2 mm was associated with a gestational age of greater than 36 weeks in 88% of fetuses, whereas a proximal tibial epiphysis greater than or equal to 3 mm was associated with a gestational age of greater than 38 weeks in 94% of fetuses. The sonographic evaluation of distal femoral epiphysis/proximal tibial epiphysis can be used as independent markers for estimation of gestational age during the third trimester, a period in which standard fetal biometric estimates of gestational age are least accurate.     

Early prenatal diagnosis of major cardiac anomalies in a high-risk population

OBJECTIVE: To examine the accuracy of early fetal echocardiography performed in a high-risk population combining transvaginal and transabdominal routes. METHODS: A series of 330 high-risk pregnancies were screened by transvaginal and transabdominal scan at 12-17 weeks' gestation in a prospective multicentre trial in Spain between September 1999 and May 2001. A total of 334 fetal heart examinations were performed, including four twin pregnancies. Maternal age ranged from 17 to 46 years (mean 33 years with 36% of women over 34 years). The median gestational age at scan was 14.2 weeks (range 12-17 weeks). For each fetus, visualization of the four-chamber view, the origin of the great arteries, aortic and ductal arches and systemic venous return was attempted in a segmental approach. B-mode and colour/pulsed Doppler flow imaging were used in all cases. The duration of complete heart examination was less than 30 minutes. The examinations were performed by three experienced operators. Reliability was assessed by conventional transabdominal echocardiography at 20-22 weeks, by postnatal follow-up in the first three months of life, and/or by autopsy in cases of termination of pregnancy. RESULTS: The rate of successful visualization of the fetal heart was 94.6% (316/334). In 48 out of 334 (14.4%) fetuses the final diagnosis was abnormal. In 38 out of 48 (79.2%) cases with heart defects the diagnosis was suspected at early echocardiography. In the group with congenital heart defects, 27 cases had an abnormal karyotype (56.3%) and 31 cases showed extracardiac anomalies (64.6%). There were 10 false-negative cases at early scan. There were no false-positive diagnoses. CONCLUSIONS: This experience stresses the usefulness of early fetal echocardiography when performed by expert operators on fetuses specifically at risk for cardiac disease. The high rate of successful visualization of the fetal heart provides a reliable diagnosis of major cardiac defects at this early stage of pregnancy.     

Ultrasonic evaluation of fetal body movements over twenty-four hours in the human fetus at twenty-four to twenty-eight weeks' gestation

Continuous 24-hour observations of fetal gross body movements were performed in 20 women between 24 and 28 weeks of gestation by means of real-time ultrasound examination. At 24 to 26 weeks, fetuses moved 13.1% +/- 0.3% of the time, which was not significantly different from the incidence of 12.4% +/- 0.8% at 26 to 28 weeks' gestation. An examination of the number of movements per hour demonstrated that fetuses at 24 to 26 weeks' gestation moved on the average 53.4 +/- 1.6 times/hr, which was significantly different from 26 to 28 weeks' gestation when fetuses made 46.2 +/- 1.4 movements/hr. When examined on an hourly basis, fetuses in both age groups demonstrated a significant increase in the number of movements overnight from 2300 to 0800 hours. Intermovement intervals were also examined. Ninety-nine percent of intervals less than 6 minutes in both age groups contained movement. The longest observed quiescent interval was 24 minutes in both age groups. These data suggest that the incidence of fetal body movements is different than that observed in fetuses during the last 10 weeks of gestation. Fetuses at 24 to 28 weeks' gestation exhibit a diurnal pattern of fetal movement and move more frequently than do older fetuses. However, these movements are of a sporadic nature and relatively short duration. Thus these fetuses do not appear to have well-defined periods of rest and activity.     

Middle cerebral artery Doppler study in fetuses with homozygous alpha-thalassaemia-1 at 12-13 weeks of gestation.

OBJECTIVE: Fetuses affected by homozygous alpha-thalassaemia-1 are anaemic from the first trimester of pregnancy. We investigated middle cerebral artery Doppler velocimetry in these affected fetuses at 12-13 weeks of gestation to assess its use in predicting fetal anaemia. METHODS: Women referred for the prenatal diagnosis of homozygous alpha-thalassaemia-1 before 14 weeks of gestation were recruited. All fetuses underwent pulsed Doppler examinations following colour flow mapping at 12 or 13 weeks of gestation. Homozygous alpha-thalassaemia-1 was diagnosed by DNA or haemoglobin study. The middle cerebral artery Doppler indices were compared between the affected fetuses and fetuses unaffected by homozygous alpha-thalassaemia-1. RESULTS: Between 1998 and 2000, 80 eligible women were recruited. Of these, 19 fetuses were affected by homozygous alpha-thalassaemia-1. Two of them showed hydropic changes at the time of Doppler study. The affected fetuses had significantly higher middle cerebral artery peak systolic velocity (V(max)) (36% increase) and time-averaged maximum velocity (V(tamx)) (33% increase). CONCLUSION: The increase of cerebral blood flow in affected fetuses is consistent with our previous finding of an increased forward flow in the ductus venosus, cardiac dilatation and an increase of cardiac output to preferentially shunt more oxygenated blood to the brain as a compensatory mechanism. However, extensive overlap of the middle cerebral artery flow velocity values between affected and unaffected fetuses precludes its use in predicting anaemia at 12-13 weeks' gestation.     

Real-time 3-D echocardiographic evaluation of the fetal heart using instantaneous volume-rendered display

AIM: Using new real-time 3-D fetal echocardiography with instantaneous volume-rendered display, we evaluated the heart anatomy of a number of normal fetuses during pregnancy. METHODS: Eighteen normal fetuses in 17 pregnancies (16 singletons and one twin) at 18-38 weeks' gestation were studied using a transabdominal real-time 3-D ultrasound machine. This machine proved capable of providing continuous 3-D sonographic images every 0.05 and 0.035 s without the need for an external workstation or other additional, costly equipment. For each patient, the fetal heart was first monitored using conventional 2-D echocardiography and was monitored again within 10 min using real-time 3-D echocardiography. RESULTS: Consecutive real-time 3-D images showing a four-chamber view, long-axis view, short-axis view, and right ventricular outflow tract view were obtained in 100%, 66.6%, 38.8%, and 22.2% of fetuses in the study, respectively. Morphological changes to each atrium or ventricle could be observed clearly and in detail throughout the cardiac cycle. The opening and closing of each valve were clearly visible. Moreover, these observations could be made from any direction. CONCLUSIONS: Real-time 3-D echocardiography provides a novel means for evaluation of the fetal heart in 3-D in real time in the second and third trimester of pregnancy. Real-time 3-D echocardiography may be an important modality in future fetal cardiac research and in evaluation of congenital heart disease in the fetus.     

Cardiac and venous blood flow in fetuses of insulin-dependent diabetic mothers: Evidence of abnormal hemodynamics in early gestation

OBJECTIVE: Our purpose was to determine whether in early gestation cardiac and venous blood flow patterns of fetuses of insulin-dependent diabetic mothers differ from those of normal fetuses.STUDY DESIGN: Serial recordings were obtained at 12, 16, and 20 weeks of gestation in 11 normal fetuses, 16 fetuses of insulin-dependent diabetic mothers with first-trimester glycosylated hemoglobin levels ≤8.5% (group 1), and 11 fetuses of insulin-dependent diabetic mothers with first-trimester glycosylated hemoglobin levels>8.5% (group 2). Velocity waveforms at the level of atrioventricular valves, inferior vena cava, and umbilical vein were recorded by means of color and pulsed Doppler equipment by either transvaginal or transabdominal approaches. The following variables were measured: ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of atrioventricular valves, percent reverse flow during atrial contraction in inferior vena cava, and pulsations in umbilical vein.RESULTS: In all the fetuses the ratios between early and active ventricular filling increased linearly with advancing gestation, whereas the percent reverse flow in the inferior vena cava decreased linearly. However, fetuses of diabetic mothers showed significant differences in the slope of the functions describing the development with gestation of these index values, resulting in lower values of the ratios between early and active ventricular filling at the level both ventricular valves and higher values of percent reverse flow in inferior vena cava. These differences were more evident in group 2 fetuses of diabetic mothers, and statistically significant differences were found in the slope values compared with group 1 fetuses. In normal fetuses umbilical vein pulsations were present only in two fetuses at 12 weeks of gestation (18.18%) and were never evidenced later in gestation. A significantly higher incidence of pulsations was found at 12 weeks in fetuses of diabetic mothers (group 1, 56.25%; group 2, 81.81%) and pulsations were present until 16 weeks (group 1, 37.5%; group 2, 45.47%).CONCUSIONS: An impaired development of cardiac and venous blood flow patterns occurs in fetuses of insulin-dependent diabetic mothers. These abnormalities are more evident in pregnancies with poorer glycemic control but still occur in the presence of stricter metabolic control.     

Prenatal measurement of testicular diameter by ultrasonography: development of fetal male gender and evaluation of testicular descent

Prenatal ultrasonography has evolved through advancements in imaging technology and observer experience. The purpose of the present study was to evaluate fetal testicular descent and diameter in relation to gestational age. A prospective cross-sectional study on 331 fetuses from an unselected population underwent a detailed assessment of testicular descent and diameter at 20-40 weeks' gestation by means of transabdominal sonography (91.2%) and transvaginal sonography (8.8%) when necessary. Fetal gender was identified in the transverse and sagittal planes and maximum testicular diameter was measured. The mean testicular diameter (in millimeters) per week and the 95% confidence interval (CI) were defined. Testicular descent was not observed prior to 23 weeks' gestation, with 6.6% of the fetuses having one testis descended at 23 weeks and 98.2% after 32 weeks. A linear relationship between testicular diameter and gestational age was observed. The present results chart the time course for testicular descent and provide a centile chart for fetal testicular diameter from 25 to 40 weeks' gestation. These findings may aid prenatal diagnosis of associated abnormal conditions as well as investigations into the clinical finding of abnormal testicular size.     

Ultrasound evaluation of fetal nasal bone at 11 to 14 weeks in a consecutive series of 1906 fetuses

OBJECTIVE: The aim of this study is to evaluate the significance of nasal bone ossification as a marker for trisomy 21 at 11 to 14 weeks' gestation in an unselected obstetric population referred to our Centre. METHODS: A total of 1906 consecutive fetuses undergoing nuchal translucency scan at 11 to 14 weeks' gestation were evaluated for the presence of hypoplasia/absence of nasal bone. The data obtained were correlated with fetal karyotype. RESULTS: A successful view of the fetal profile was obtained in 1752 fetuses (91.9%). The nasal bone was hypoplastic/absent in 12 of 19 fetuses with chromosomal abnormalities. There were 10 cases of trisomy 21, in 8 of which hypoplastic/absent nasal bone was observed. Furthermore, absence of nasal bone was recorded in 24 of 1733 chromosomally normal fetuses. CONCLUSIONS: Nasal bone evaluation may improve the detection of trisomy 21 in the first trimester in an unselected obstetric population. Although numerically limited, our experience confirms that delayed nasal bone ossification (hypoplasia/absence of nasal bone) is rarely observed in chromosomally normal fetuses (1.4%). An appropriate training of operators is mandatory in order to achieve an acceptable performance.     

Fetal screening of congenital heart disease

Echocardiograms of two hundred and ninety normal fetuses at 18-39 weeks of gestation were studied with a real-time linear scanner (3.5 MHz). Aortic valvular diameter, pulmonary valvular diameter, mitral valvular diameter, tricuspid valvular diameter and total cardiac dimension were measured. These parameters increased with fetal growth. The ratios of pulmonary to aortic valvular diameter and of tricuspid to mitral valvular diameter were more than 1, suggesting right ventricular dominance in the fetal hearts. The cardio-thoracic ratio was about 50% in this period. The four-chamber view, left ventricular long-axis view, ventricular short-axis view, short-axis view of the great arteries, the view of the aortic arch and the view of the inferior and superior vena cava were also recorded. These six views could be obtained in 9.8% of all subjects at the same time. Detection rates for these views were the greatest in pregnancy at 22-33 (especially 28-29) weeks of gestation. The ventricular short-axis view and short-axis view of the great arteries were easily detected in the dorsoposterior position, whereas the view of the aortic arch was obtained in the dorsoanterior position. It was concluded that fetal echocardiography needed to be performed at least twice, at 22-23 and 28-29 weeks of gestation, and this would be useful in diagnosing some congenital heart diseases.     

Fetal echocardiography. VIII. Aortic root dilatation--a marker for tetralogy of Fallot

Tetralogy of Fallot has increased in incidence during the past decade. Although abnormalities of the four-chamber screening examination of the fetal heart identifies structural anomalies associated with semilunar and atrioventricular valve hypoplasias, the anomalies associated with tetralogy of Fallot are not as readily identifiable from the four-chamber view alone. This study was designed to determine whether aortic root dilatation, commonly observed in the newborn with tetralogy of Fallot, is a marker for tetralogy of Fallot diagnosed in utero. In 45 normal (control) fetuses the biparietal diameter, head circumference, abdominal circumference, and femur length were measured and M-mode measurements were made of the biventricular outer dimension and aortic root dimension. The aortic root dimension from seven fetuses (18, 19, 20, 23, 32, 33, and 34 weeks' gestation) with tetralogy of Fallot was increased in dimension when compared with cardiac (biventricular outer dimension) and noncardiac biparietal diameter, head and abdomen circumferences, and femur length parameters. In conclusion, incorporation of aortic root imaging with the four-chamber view of the fetal heart during a routine screening examination allows for identification of fetuses with tetralogy of Fallot.