Second-trimester Fetuses Research Articles

Mid-facial anthropometry in second-trimester fetuses with trisomy 21: a three-dimensional ultrasound study

The aim of this study was to evaluate whether fetuses with trisomy 21 and detectable nasal bones have a distinct facial anthropometry that can be objectively defined using three-dimensional (3D) ultrasonography. A prospective cross-sectional study of 40 fetuses in the second trimester, 17 with trisomy 21 and 23 controls, was performed. The 3D volume datasets of each case were evaluated for documentation of the nasal bones using the multiplanar and the maximum mode. The nasal bone length and the angle formed by the two maxillary bones at the level of the frontal process were then measured. The nasal bones were absent in 7 (41%) of the 17 fetuses with Down syndrome. All of the 23 normal fetuses had detectable nasal bones. The difference between nasal bone length in trisomy 21 fetuses and controls did not reach statistical significance (p = 0.087). The mean maxillary angle in trisomy 21 fetuses with nasal bones was significantly wider compared to controls (p = 0.029). The nasal bones are present in the majority of fetuses with trisomy 21 in the second trimester. This group of fetuses has a characteristic mid-facial anthropometry (wider maxillary angle) that can be assessed by means of 3D ultrasonography.

Cardiac screening examination of the fetus: guidelines for performing the ‘basic’ and ‘extended basic’ cardiac scan

Cardiac screening examination of the fetus: guidelines for performing the ‘basic’ and ‘extended basic’ cardiac scan

Variation of Fetal Nasal Bone Length in Second-Trimester Fetuses According to Race and Ethnicity

The purpose of this study was to determine the influence of race and ethnicity on the expected nasal bone length (NBL) based on biparietal diameter (BPD) measured in second-trimester fetuses. We searched our ultrasound, obstetric, and cytogenetic databases for all second-trimester fetuses with measured NBLs. Fetuses with Down syndrome were identified and excluded from the analysis. Linear regression curves were generated for NBL by BPD according to race and ethnicity. Categories used were African American, Hispanic, Asian, and white. Analysis of variance was used to compare mean variation of observed from expected NBL by BPD according to race and ethnicity. There were 717 fetuses with NBL-by-BPD pairs who were available for analysis in our population, including 139 African American, 58 Hispanic, 22 Asian, and 498 white fetuses. Nasal bone length was highly correlated with BPD for each race (P < .001). Mean variances of observed from expected NBL by BPD were statistically different according to race or ethnicity (P = .0092). Race and ethnicity significantly affect the mean regression line of expected NBL by BPD among fetuses in the second trimester. Genetic sonographic norms, therefore, appear to require race- and ethnicity-specific formulas for NBL.

In‐utero intervention for hypoplastic left heart syndrome — a perinatologist's perspective

.Today,whenHLHSisdiagnosedinthenewborn,or suspected by prenatal ultrasound studies, surgicalinterventions typically take one of two directions – eitherthe multistaged reconstruction pioneered by Norwood toenable single ventricle survival or cardiac transplantation.Compassionate care, although increasingly controversial,remains an option in some centers. Although increasingsurvival rates following both multi-staged surgery ortransplant are being reported, the nature of theseinterventions is such that these children remain at lifelongrisk for cardiac and neurologic morbidity.Consideration of HLHS as a candidate for

Effect of Age on the Frequency, Cell Cycle, and Lineage Maturation of Rhesus Monkey (Macaca mulatta) CD34+ and Hematopoietic Progenitor Cells

The effects of maturation and aging on hematopoietic progenitor cells, blood and bone marrow from second- and third-trimester fetal, newborn, infant, adult, and aged rhesus monkeys (Macaca mulatta) were analyzed. CD34(+) cells were immunoselected and stained with propidium iodide for cell cycle analysis. Blood and bone marrow mononuclear cells were plated in methylcellulose, and erythroid and myeloid progenitors were grown and counted. A higher frequency of circulating CD34(+)CD38(-) and CD34(+)DR(-) cells was observed in second-trimester fetuses compared with the other age groups. The frequency of bone marrow CD34(+)CD38(-) and CD34(+)DR(-) cells declined in adult and aged animals when compared with the younger age groups. Cell-cycle analysis showed 4.5% second-trimester fetal bone marrow CD34(+) cells entering the G(2)/M phase, compared with 1.7% CD34(+) cells in aged animals. More than 95% of circulating CD34(+) cells remained quiescent for most age groups, except for second-trimester fetuses. Adult marrow myeloid progenitors were found in a lower quantity when compared with third-trimester fetuses, whereas erythroid progenitors were greatest in early-gestation fetuses and adults. The results of these studies suggest that 1) the greatest quantity of CD34(+)CD38(-) and CD34(+)DR(-) cells was found in fetal and infant bone marrow, 2) the frequency of cycling CD34(+) cells declines with maturation and aging, and 3) an age-dependent difference in lineage commitment occurs.

How Sonographic Tomography Will Change the Face of Obstetric Sonography

This study was undertaken to determine whether 3-dimensional (3D) volume sonography (sonographic tomography) can yield a far quicker and equally accurate anatomic examination of the second-trimester fetus compared with traditional 2-dimensional (2D) scanning. Twenty-five consecutive second-trimester fetuses with normal structural surveys on standard 2D imaging underwent 5 standard 3D volume acquisitions each (in the regions of the head, chest, abdomen, face, and lower extremities) immediately after the 2D scan. The 2D and 3D images were subsequently compared in relation to the completeness of the fetal survey, measurements of the biparietal diameter and femur length, and time required to obtain the fetal survey. The structural surveys were complete in 20 of 25 cases using 3D reconstructed volumes. One fetus had an incomplete evaluation of the face on 3D volumes (and limited on 2D imaging because of the prone position of the fetus). The other 4 fetuses with incomplete surveys done on 3D volumes had missing images of a hand or foot. Three-dimensional reconstructions slightly overmeasured the biparietal diameter compared with the 2D reference standard (mean difference, 1.1 mm; P < .001). For femur length, the mean difference was not statistically significant. It took a mean time of 1.1 minutes to obtain the 3D volumes and 5.5 minutes to reconstruct the complete surveys by the 3D volume method. With the standard 2D technique, the structural surveys were done in a mean time of 13.9 minutes. The mean time difference between both methods was 7.3 minutes (P = 2.4 x 10(-9)). Using 3D volume acquisition, it is feasible to perform and interpret a structural survey in half the time in which a 2D survey is performed. Further research is necessary to standardize the acquisition of volumes to minimize artifacts and produce uniform images.

Massive myocardial calcification in second‐trimester fetuses: antenatal detection and causes

Massive myocardial calcifications were detected by antenatal ultrasound examination in four second-trimester fetuses. In one fetus, multiple cardiac rhabdomyomas were the initial diagnosis. One fetus presented with arthrogryposis and the brain and spinal cord showed severe hypoxic-ischemic damage. One fetus was hydropic and had severe cardiac malformations. The fourth fetus had congenital heart block and maternal serum was positive for anti-Ro and anti-La antibodies. Myocardial calcifications in the first three fetuses were most likely to be caused by hypoxic-ischemic damage to the heart, and immunological mechanisms were responsible in the other fetus. Antenatally detected myocardial echogenic foci in a fetus leading to a termination of pregnancy or associated with fetal death should be investigated with a full postmortem examination. It is important to confirm the presence of calcifications as distinct from a rhabdomyoma as genetic counseling is completely different. The demonstration of associated lesions in other organs also helps to explain the pathogenesis underlying this condition.

Prenatal diagnosis of jumping translocation involving chromosome 22 with ultrasonographic findings

We report on the prenatal diagnosis and ultrasonographic findings of a second-trimester fetus with jumping translocation involving chromosome 22. A 28-year-old gravida 2, partus 1, Turkish woman was referred for genetic counselling and ultrasonographic examination at 18 weeks' gestation because of a high risk of trisomy 21 in triple test. Prenatal ultrasonography showed tetralogy of Fallot with a diverticular dilatation of the pulmonary artery, flattened brow, complete absence of the right upper limb, hypospadias, oligodactyly (three digits) in left hand and in both feet, and hyperechogenic abdominal foci. Amniocentesis revealed a karyotype of 46,XY[4]/46,XY,-8,+ der(8),t(8;22)(q24.3;q11.21)[2]/45, XY,-22,-8,+ der(8)t(8;22)(q24.3;q11.21)[22]/45,XY,-22,-5,+ der(5)t(5;22)(q35.3;q11.21)[44]. A C-banding and FISH study with a specific centromeric probe (D14Z1/D22Z1) for chromosome 22 was made. In our case, partial monosomy for the regions 22q11.21-->22pter, 8q24.3-->8qter and 5q35.3-->5qter may partially explain the fetal malformations.

Three‐dimensional ultrasound with maximal mode rendering: a novel technique for the diagnosis of bilateral or unilateral absence or hypoplasia of nasal bones in second‐trimester screening for Down syndrome

Three-dimensional (3D) ultrasound of the fetal face with maximal mode rendering allows accurate visualization of the bony face and the distinct demonstration of both nasal bones in second-trimester fetuses. The aim of this study was to analyze the feasibility of assessing nasal bones spatially on prenatal ultrasound in second- and third-trimester fetuses with present and absent nasal bones. The faces of 38 fetuses between 17 and 33 weeks' gestation were examined with 3D ultrasound and volumes were stored for offline evaluation. Eighteen fetuses had normal karyotype and an apparently normal nasal bone on 2D ultrasound; these were examined to standardize the 3D rendering technique. Twenty fetuses had trisomy 21. In all 18 healthy fetuses both nasal bones could be demonstrated on 3D ultrasound. Nine of the 20 Down syndrome fetuses had a hypoplastic or absent nasal bone on two-dimensional ultrasound. On 3D ultrasound three of the nine had discrepant findings between left and right nasal bones with evidence of absence of one side, and hypoplasia (n = 2) or normal length (n = 1) of the other. Unilateral absence or hypoplasia of nasal bones is an important and new observation in fetuses with Down syndrome. This differentiation is best demonstrated on 3D ultrasound with maximal mode rendering. This observation of unilaterality of findings could explain some discrepant findings on absence of nasal bones on two-dimensional ultrasound but their "presence" on lateral postmortem radiographs.

Racial differences in the frequency of echogenic intracardiac foci in second trimester fetuses

SECOND TRIMESTER FETUSES CRYSTAL JOHNSON, LISA HOLLIER, JOAN MASTROBATTISTA, University of Texas Health Science Center at Houston, Obstetrics, Gynecology, and Repro Sci, Houston, Texas OBJECTIVE: To determine the prevalence of echogenic intracardiac foci (EIF) in a racially diverse population in second trimester fetuses who are both at low risk and high risk for aneuploidy. STUDY DESIGN: Our ultrasound (US) database was queried from May 2003 to May 2004, for obstetric US examinations from 14 to 22 weeks gestation. All exams were performed transabdominally, and only one exam per fetus was utilized. Multiple gestations and cases without documented ethnicity were excluded. Maternal race was determined by the attending physician and patient self-assignment into the following categories: Caucasian, Hispanic, African American, and Asian (Vietnamese, Chinese, Filipino, Japanese, Eastern Indian/ Pakistani). Maternal age, gravidity and parity, and the presence of EIF were evaluated. The prevalence of EIF was compared between different racial groups. Statistical analyses included Student’s t test for continuous variables, c for categorical variables, and multivariate logistic regression. RESULTS: 4762 US exams were reviewed; 168 (3.5%) fetuses with EIFs were identified. Significant differences in the percentage of EIF were demonstrated between ethnic groups: African American-5.5%, Asian-4.0%, Caucasian-2.5%, and Hispanic-2.3% (P ! .001). The odds of EIF were increased for African Americans compared to the other ethnic groups (OR 2.3, 95% CI 1.7, 3.2). EIF were found in 3.9% in women !35 years of age (low risk population) and in 2.6% in women R35 years (high risk population) (P = .03). Median gravidity (P! .001) and parity (P = .04) differed between cases and controls. Adjustment for age and parity did not change the odds of EIF for African Americans. CONCLUSION: EIF prevalence varies in different ethnic groups. A greater proportion of EIFs were found in the African American and Asian populations. Variations in the frequency of soft US markers, such as EIF, among ethnic groups may be important in risk counseling. SMFM Abstracts S177

Use of the mitral valve–tricuspid valve distance as a marker of fetal endocardial cushion defects

The purpose of this study was to compare the mitral valve-tricuspid valve distance in second-trimester fetuses with normal cardiac anatomy versus those fetuses with endocardial cushion defects. We identified fetuses between 16 and 24 weeks of gestation. The distance between the insertions of the medial leaflets of the mitral and tricuspid valves were obtained. Linear regression curves were generated. The mean mitral valve-tricuspid valve distance for 86 fetuses with normal cardiac anatomy was 2.02 mm, compared with 0.37 mm in 13 fetuses with endocardial cushion defects ( P = .0001). Linear regression curve correlating mitral valve-tricuspid valve distance with gestational age showed a gradual slope (R 2 = 0.28; P < .0001). With a mitral valve-tricuspid valve distance < 5th percentile as a marker for the diagnosis of endocardial cushion defect gave a sensitivity of 69.2%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 95.6%, and a false-positive rate of 0% ( P = .0001). The mitral valve-tricuspid valve distance is useful clinically in the detection of endocardial cushion defects in second-trimester fetuses.

Absent Nasal Bone: A Specific Marker for Second-Trimester Fetuses with Down Syndrome. UMNDJ???Robert Wood Johnson Medical School Piscataway, NJ.

Literature Reviews: SELECTED ABSTRACTS FROM THE OFFICIAL PROCEEDINGS OF THE 10TH CONGRESS OF THE WORLD FEDERATION FOR ULTRASOUND IN MEDICINE AND BIOLOGY: Obstetric Ultrasound: Obstetric Ultrasound: Genetics/Fetal Anomalies

Variation of fetal humeral length in second-trimester fetuses according to race and ethnicity.

To determine the influence of race and ethnicity on the expected humeral length based on biparietal diameter measured in second-trimester fetuses. We searched our ultrasound, obstetric, and cytogenetic databases from 1995 through 2001 for all fetuses who underwent an anatomic survey between 15 and 22 weeks' gestation. Fetuses with Down syndrome were identified and removed for separate analysis. Linear regression curves were generated for humeral length by biparietal diameter according to race and ethnicity. Analysis of variance was used to compare the mean variation of observed from expected humeral length by biparietal diameter according to race and ethnicity. There were 11,278 humeral length-by-biparietal diameter pairs that were available for analysis in our population, including 4202 African American, 2269 Hispanic, 639 Asian, and 4168 white fetuses. Humeral length was highly correlated with biparietal diameter for each race (R2 = 0.8). There were no differences in mean variances according to race or ethnicity (P = .75). Race and ethnicity do not affect the mean regression line of expected humeral length by biparietal diameter among fetuses in the second trimester. Genetic sonographic norms, therefore, do not require race- or ethnic-specific formulas for humeral length.

Variation of fetal humeral length in second-trimester fetuses according to race and ethnicity

Objective. To determine the influence of race and ethnicity on the expected humeral length based on biparietal diameter measured in second-trimester fetuses. Methods. We searched our ultrasound, obstetric, and cytogenetic databases from 1995 through 2001 for all fetuses who underwent an anatomic survey between 15 and 22 weeks' gestation. Fetuses with Down syndrome were identified and removed for separate analysis. Linear regression curves were generated for humeral length by biparietal diameter according to race and ethnicity. Analysis of variance was used to compare the mean variation of observed from expected humeral length by biparietal diameter according to race and ethnicity. Results. There were 11,278 humeral length-by-biparietal diameter pairs that were available for analysis in our population, including 4202 African American, 2269 Hispanic, 639 Asian, and 4168 white fetuses. Humeral length was highly correlated with biparietal diameter for each race (R 2 = 0.8). There were no differences in mean variances according to race or ethnicity (P = .75). Conclusions. Race and ethnicity do not affect the mean regression line of expected humeral length by biparietal diameter among fetuses in the second trimester. Genetic sonographic norms, therefore, do not require race- or ethnic-specific formulas for humeral length.

Absent nasal bone: a specific marker for second-trimester fetuses with Down syndrome

Absent nasal bone: a specific marker for second-trimester fetuses with Down syndrome

Absent nasal bone in the prenatal detection of fetuses with trisomy 21 in a high-risk population

Objective To estimate the usefulness of absent nasal bone by ultrasound in the prenatal detection of second-trimester fetuses with trisomy 21. Methods This was a matched case–control study of sonograms from January 1, 1997 to April 30, 2002. Genetic sonograms and facial profile pictures of all fetuses that were subsequently proven to have trisomy 21 were reviewed (study group). A control group was identified during the same study period by using a 4-to-1 ratio matching for gestational age at the time of the ultrasound examination. The sensitivity and specificity of absent fetal nasal bone for trisomy 21 were determined, and overlap with other ultrasound aneuploidy markers was assessed. Results Forty fetuses were identified with trisomy 21; in 29 (72.5%) a facial profile had been obtained. Of the 160 controls, 102 (64%) had facial profiles documented. Of the 29 fetuses with trisomy 21 with facial profile available, 12 had absent nasal bone (sensitivity 41%). None of the 102 control fetuses with facial profiles available had absent nasal bone (specificity 100%). The sensitivity of genetic ultrasound was increased from 83% (24 of 29) to 90% (26 of 29) by adding absent nasal bone to the other ultrasound aneuploidy markers. Conclusion In the second trimester of pregnancy, absent nasal bone has a sensitivity of 41% and a specificity of 100% in detecting fetal trisomy 21. Absent fetal nasal bone may be added to the list of ultrasound aneuploidy markers evaluated during a genetic sonogram.

The role of fetal echocardiography in genetic sonography

Genetic sonography identifies between 60% and 93% of fetuses with trisomy 21. One of the reasons for the variation in sensitivity is because of the under-detection of congenital heart defects. Although congenital heart defects are present in 56% of second trimester fetuses and 44% of newborns with trisomy 21, most studies evaluating second-trimester fetuses at risk for trisomy 21 detect less than 10% of heart malformations. This review discusses an approach that allows the fetal sonographer to incorporate fetal echocardiography, based upon the examiner's level of skill and experience, when evaluating the fetus at risk for trisomy 21. The cardiovascular examination consists of three levels. In the Level I examination only noncardiac markers are evaluated for a detection rate of 60% and false-positive rate of 5.9%. The Level II examination incorporates the four-chamber view with non-cardiac markers. If the examiner can identify atrial and/or ventricular chamber disproportion, then the sensitivity is increased to 75%, with a false-positive rate of 6.4%. The Level III examination utilizes grayscale and color Doppler ultrasound to evaluate the fetal heart. If the examiner can identify ventricular septal defects, atrioventricular septal defects, pericardial effusion, tricuspid regurgitation, and chamber disproportion, then the sensitivity of genetic sonography increases to 91% with a false-positive rate of 14%. This review includes Likelihood Ratios for each of the ultrasound markers so that the examiner can compute the risk for trisomy 21 for an individual patient.

The clinical implications of fetal echogenic bowel

Echogenic bowel is detected in 0.6–1% of second-trimester fetuses. It has a well-recognised association with a number of fetal conditions, including chromosomal abnormality, cystic fibrosis, subchorionic haemorrhage, bowel obstruction, viral infection and intrauterine growth retardation. The objective of our study was to assess the clinical outcome in fetuses with isolated and complex echogenic bowel. We conducted a prospective observational study of all second trimester fetuses with echogenic bowel as bright as fetal bone. Virology, cystic fibrosis screening and karyotyping was offered in all cases and infants were followed-up between 6 and 12 months of age. Echogenic bowel was identified in 232 cases. It was an isolated finding in 129 (56%) and was found in association with other abnormalities (complex) in 103 (44%). In the isolated cases 67% babies had a normal outcome compared to 27% in the complex group.

New ultrasonographic markers of aneuploidies: nasal bones

ABSTRACTThe ultrasound sign of the absence of nasal bones in aneuploidies is discussed. Among several skeletal abnormalities in trisomy 21 fetuses, the absence or delay in the development of the nasal bones has been described by radiological and histological studies. The finding of absent nasal bones is recognizable by prenatal ultrasound examinations in first- and second-trimester fetuses, and about two-thirds of fetuses with trisomy 21 reveal absent nasal bones. There is evidence that an appropriate technique is required to visualize the fetal nasal bones by ultrasound. As, from preliminary studies, the absence of nasal bones does not appear to be related to fetal nuchal thickness, the two signs could be combined in a single test for prenatal screening of trisomy 21 that seems to be very accurate.Prenatal ultrasound studies have shown the absence of nasal bone visualization also in first-trimester fetuses affected by trisomy 18, Turner's syndrome and trisomy 9.

Prenatal diagnosis of 22q11 microdeletion in an early second‐trimester fetus with conotruncal anomaly presenting with increased nuchal translucency and bilateral intracardiac echogenic foci

We report on a 16-week fetus, in which detection of increased nuchal translucency thickness and bilateral intracardiac echogenic foci led to the prenatal diagnosis of truncus arteriosus communis, interruption of the aortic arch and aplastic thymus. Cytogenetic examination confirmed a 22q11.2 microdeletion consistent with the suspected CATCH 22 syndrome. Subsequently hydrops fetalis developed and the fetus died in utero at 18 weeks. This case report supports the hypothesis that both cardiac failure and left ventricular outflow tract obstruction may cause increased nuchal translucency thickness. The association between increased nuchal translucency thickness and CATCH 22 syndrome should be considered in diagnostic procedures. The sonographic diagnosis of both increased nuchal translucency thickness and intracardiac echogenic foci requires specialist ultrasonography and echocardiography. In particular, identification of right-sided or bilateral echogenic foci should prompt further detailed examination.