Objective: This study was undertaken to evaluate the relationship of an isolated fetal intracardiac echogenic focus in a population of patients with a mixed risk for aneuploidy when presenting for prenatal diagnosis.Study design: All women referred to our institution for screening ultrasound were prospectively evaluated for the presence of an intracardiac echogenic focus in the fetal heart. Each patient was evaluated for the presence of clinical risk factors including ultrasound findings, biochemical screening, and maternal age. The population of patients was then described and neonatal outcomes were obtained.Results: A total of 10,875 patients were referred and 176 cases of fetal intracardiac echogenic foci were evaluated. There was an overall prevalence of 1.6% in our population. The patients with other ultrasound findings and/or maternal age older than 35 years who underwent amniocentesis had 3 abnormal karyotypes identified and had identifiable risk factors. In the group less than 35 years, the relative risk was 2.55 of having an amniocentesis for an isolated echogenic focus (with no cases of fetal aneuploidy found) in comparison with our referred group of nonadvanced maternal age patients without any ultrasound markers or findings.Conclusion: This isolated echogenic finding appears to be a benign variant and not an increased risk for fetal aneuploidy. The chromosomal abnormalities were seen in the group with risk factors including maternal age and/or other ultrasound findings. Evaluation of maternal age, biochemical markers, and ultrasound markers should be used together to help determine the risk of patients with an isolated echogenic focus. (c) 2005 Mosby, Inc. All rights reserved.

Objective. A multicenter study was undertaken to evaluate the diagnostic efficacy of a genetic sonogram. Methods. Eight centers provided data on 176 pregnancies complicated by fetal Down syndrome. One hundred thirty‐four pregnancies were considered high risk because of advanced maternal age (>35 years), and 42 were considered high risk for having “abnormal” triple‐screen results (risk >1:250). Each center provided fetal biometric data, information regarding the presence or absence of major structural abnormalities, and between 3 and 6 additional ultrasonographic markers for trisomy 21. The heterogeneity of our 8 independent “sensitivity estimates” was evaluated by Poisson regression, and a single combined estimate of the sensitivity was calculated. Results. Of the total 176 cases of trisomy 21, 125 fetuses (71.0%) had either an abnormal long bone length (femur length, humerus length, or both), a major structural abnormality, or a Down syndrome marker. The combined diagnostic sensitivity was 71.6%, with a range of 63.6% (7 of 11) to 80% (8 of 10). Five centers had sensitivity estimates falling between 64% and 76%. The sensitivity of individual markers varied between 3% (sandal gap) and 46.5% (nuchal skin fold thickness). A condensed regimen of nuchal skin fold thickness, femur length, and a standard anatomic survey would screen in 56.8% of fetuses with Down syndrome. Conclusions. This 8‐center study that included many fetuses with Down syndrome validates the concept that the genetic sonogram can be used to better adjust the Down syndrome risk for high‐risk patients.

Sex identification is one of the prime expectations of any parent during the prenatal ultrasound examination. However, the ability to visualize fetal genitalia not only has important social implications but also has considerable medical implications. Various endocrine disorders and complex genitourinary malformations can be manifested in the form of anomalous genitalia, and a delay in diagnosis may lead to an increase-in postnatal morbidity and mortality.(1) In addition, correctly identifying and illustrating major fetal anomalies is of paramount importance to the parents, whose decisions regarding possible termination will directly affect the course of the pregnancy. Prenatal detection of genital abnormalities is therefore helpful in evaluating those fetuses with severe multisystem diseases and those with disorders more easily corrected with prenatal and neonatal treatments. Ambiguous genitalia is a condition that affects approximately 1 per 5000 live-born infants. Until the inception of three-dimensional (3D) ultrasonography, two-dimensional (2D) ultrasonography was the only method available to visually detect cases of ambiguous genitalia. A review of the literature reveals several case reports and small case series of prenatal identification of abnormal fetal genitalia during targeted 2D ultrasonographic surveys. However, the limitations of a standard 2D fetal sonogram are often evident. We present a case of ambiguous fetal genitalia whose diagnosis was both correctly identified and visually clarified by the use of prenatal 3D ultrasonography.

To evaluate the extent that associated findings aid in the differential diagnosis and/or prognosis of fetal echogenic bowel.

Objective: To describe the karyotypes of a population of fetuses with choroid plexus cysts and compare affected fetuses with and without additional ultrasonographic findings. Methods: The study population included all patients undergoing second-trimester ultrasound examination in a prenatal diagnostic program between January 1993 and October 1995. The records of all cases in which a choroid plexus cyst was found were reviewed, and information was abstracted regarding the fetal karyotype and the presence of other sonographic abnormalities. Results: Two hundred ten cases of choroid plexus cysts were identified among 7617 patients (2.8%) who underwent second-trimester ultrasound examination. The majority of the cases (181, or 86%) involved isolated choroid plexus cysts and the remaining 29 (14%) were associated with additional ultrasonographic findings. Autosomal aneuploidy was found in one patient with an isolated choroid plexus cyst (trisomy 21) and in another with additional findings (trisomy 18); the mothers of both of these patients were at least 35 years old. For those fetuses with known outcome, the risk of aneuploidy with isolated choroid plexus cyst (one in 180) was not statistically significantly different from that associated with choroid plexus cyst accompanied by other sonographic findings (one in 26). More than 1000 fetuses with choroid plexus cysts would have to be studied to determine whether such a difference was real. Conclusion: Because of the rarity of aneuploidy, the reported risk for a fetus with an isolated choroid plexus cyst must be interpreted cautiously and should include the baseline risk.

Objective: To determine the distribution of nuchal skinfold thickness in normal and Down syndrome pregnancies and to evaluate the use of this sonographic measurement as a screening test for fetal Down syndrome.Methods: A prospective, multicenter, population-based study was performed by experienced obstetric sonographers on 1382 women with sonographically normal fetuses undergoing second-trimester amniocentesis for the indication of advanced maternal age. A standard, well-defined sonographic image was obtained at all collaborating centers. The distributions of nuchal skinfold thickness were compared between euploid and Down syndrome fetuses.Results: There were 1346 chromosomally normal pregnancies, 13 fetuses with Down syndrome (1:106), and 23 other chromosome abnormalities. Seventeen fetuses had measurements of 6 mm or greater, and one of these had Down syndrome. The median nuchal skinfold thickness in Down syndrome was 3.2 mm and in euploid fetuses was 3.1 mm. By the Mann-Whitney rank-sum test, there was no statistically significant difference in nuchal skinfold between the euploid and Down syndrome fetuses (P = .5). Overall, using a nuchal skinfold thickness of 6 mm or greater as a screening test, the detection rate for Down syndrome was one of 13 (8%), the false-positive rate was 16 of 1382 (1.2%), the positive predictive value was one of 17 (6%), and the probability of detecting Down syndrome was 6.5%.Conclusion: In this investigation, excess nuchal skinfold thickness was a poor and unreliable screening test for Down syndrome.

OBJECTIVE:To identify the characteristics of patients associated with optimal utilization of Tay-Sachs screening.METHODS:Medical records of patients undergoing amniocentesis for genetic diagnosis were reviewed. Three hundred twenty-nine of 537 charts evaluated were from individuals at risk for Tay-Sachs heterozygosity. Among these, 213 couples had previously been screened for Tay-Sachs. In 116 couples, neither member of the couple had been screened before amniocentesis. A concurrent reference group consisted of 208 couples without an indication for Tay-Sachs screening. Patient characteristics, including ethnicity, genetic screening history, parental ages, and pregnancy history, were reviewed for each group. Analysis of variance and likelihood chi 2 test were used for statistical analysis.RESULTS:There were no significant differences in maternal age or reproductive history among the groups. The most common indication for amniocentesis was advanced maternal age for all three groups. However, the previously screened group was more than twice as likely to self-refer because of a positive family history or patient anxiety than was the unscreened group (P = .006). Conversely, the unscreened group was more than twice as likely as screened couples to be referred because of a positive high or positive low maternal serum alpha-fetoprotein level (P = .002).CONCLUSION:Despite 2 decades of professional and lay education, many couples are unaware of their individual risk for Tay-Sachs heterozygosity. Additional education, most likely at the professional level, is needed to maximize informed participation.

OBJECTIVE:The purpose of this study was to determine the value of discordant morphometric measurements as identifiers of Down syndrome by evaluating the relationship of biparietal diameter, femur length, biparietal diameter/femur length ratio, and cephalic index between a group of fetuses with trisomy 21 and a control population.STUDY DESIGN:Biometric measurements from 48 fetuses with trisomy were reviewed and compared with 107 normal fetuses of similar gestational age. Data were analyzed in 2-week gestational age intervals to determine the effect of gestational age on ultrasonographic detection of Down syndrome. Outcome measures were subject to least-squares linear regression and the t test for analysis.RESULTS:A positive relationship between abnormal morphometric measurements and fetuses with Down syndrome was detected but only during specific weeks of pregnancy.CONCLUSION:Although it appears that biometric measurements may be useful for Down syndrome, further study is needed before its widespread introduction into clinical practice.

Advances in prenatal diagnosis provide new opportunities for patients and their physicians to distinguish the abnormal from the normal fetus. Demands from women to learn about their fetuses earlier in pregnancy have pushed investigators to identify new methods that are useful in the first trimester. The prenatal diagnosis of many disorders, such as the fragile X syndrome, cystic fibrosis, hemoglobinopathies, inborn errors of metabolism, and hundreds of mapped inherited syndromes, is possible today with the use of molecular techniques. However, the detection of Down's syndrome is still the primary reason women seek prenatal diagnosis. Parental decisions on how to respond . . .

Our definition of hydramnios is an amniotic fluid index of 24 cm or greater. We evaluated by ultrasound examination 49 consecutive patients who met this definition of hydramnios. Of these, 22 (44.9%) had anomalies visible by ultrasound. The combination of hydramnios, abnormal hand posturing, and any other anomaly created a constellation of sonographic findings enabling us to predict six specific autosomal trisomies (27.27%): three trisomy 18, two trisomy 21, and one trisomy 13. The 27 fetuses with "idiopathic hydramnios" (no identifiable anomaly or abnormal hand posturing) had normal karyotypes. We recommend that any patient with confirmed hydramnios have a detailed ultrasound examination by an experienced sonographer, with special attention paid to the heart, face, and hands. If no abnormality is seen and the hands are normally postured, expectant management may be appropriate. If the late second- or third-trimester fetus displays abnormal hand posturing with any other abnormality, rapid karyotyping by funipuncture or placental biopsy should be recommended to facilitate appropriate management.

The purpose of this study is to evaluate the use of transvaginal ultrasound in the diagnosis of placenta previa and to assess the risk of bleeding secondary to the placement of the vaginal transducer. Thirty‐eight patients with an estimated gestational age equal to or greater than 26 weeks and the diagnosis of suspected placenta previa gave their consent and were randomized to two groups. Randomization was stratified by patient weight and anterior or posterior placental location. Group 1 ( n = 20) had complete obstetric ultrasounds using linear and sector transducers. Group 2 ( n = 18) had similar examinations followed by transvaginal ultrasound scans. Patients were rescanned to follow placental location and fetal growth parameters. On abdominal ultrasound, the posterior placenta ( n = 17) was often shadowed by fetal parts. The ease of placental visualization was rated on a four‐point scale with 1 being the clearest. The mean clarity score for posterior placentas on abdominal ultrasound in Group 2 was 1.6 and on transvaginal ultrasound was 1.0, p < 0.04. The use of transvaginal ultrasound consistently revealed greater clarity of diagnosis in these patients. No patient in either group experienced increased vaginal bleeding following the scanning sessions. Transvaginal ultrasound was most beneficial for those patients with posterior placenta previas because of increased clarity of diagnosis, decreased time of scanning, and no increased incidence of hemorrhage. Copyright © 1992 International Society of Ultrasound in Obstetrics and Gynecology

Controversy surrounds the issue of recommending cytogenetic studies in second-trimester fetuses with fetal choroid plexus cysts. To assist in clarifying this issue, a prospective study was designed to describe the association between fetal choroid plexus cysts and aneuploidy in a large population. During a 3-year period 7350 women at 15 to 22 weeks' gestation underwent an ultrasonographic evaluation. Fetal choroid plexus cysts were diagnosed in 71 (0.96%) of these pregnancies. Sixty-two of the 71 patients elected to undergo amniocentesis. An abnormal karyotype was identified in four (6.4%) of these fetuses. One fetus had trisomy 21, and three fetuses were diagnosed with trisomy 18. These data indicate that it is reasonable to offer genetic counseling and cytogenetic studies in those patients identified as having a fetal choroid plexus cyst.

To delineate any possible prognostic indicators, we reviewed the ultrasonographic and nonmorphometric findings in 19 antenatally diagnosed cases of nonimmune hydrops fetalis in which it was chosen to continue the pregnancy. Thirteen fetuses died and six survived. Of all parameters examined, including associated anomalies, abnormal karyotype, location of serous fluid, anemia, and possible cause of nonimmune hydrops fetalis, the most sensitive prognostic indicator was the real-time-directed M-mode echocardiographic measurement of the biventricular outer dimension in diastole. All fetuses with biventricular outer dimensions > 95% died, whereas all but one with normal biventricular outer dimensions had resolution of nonimmune hydrops fetalis and survived. This was highly significant (p < 0.001) with the predictive value of a normal biventricular outer dimension being 86% and the predictive value of an enlarged biventricular outer dimension being 100%.

The purpose of this study was to describe the ultrasonic measurement of fetal foot length and to develop mathematical models to quantify the relationships between menstrual age and commonly measured fetal structures. We evaluated 120 patients with known last menstrual periods and normal pregnancies to develop a cross-sectional study population. All patients had ultrasonic measurement of the fetal foot length, biparietal diameter, head circumference, abdominal circumference, and femur length. Least-squares estimation of linear models was used to select the best mathematical models to describe the relationship between menstrual age and fetal foot length. A similar evaluation of the relationship between fetal foot length and the other measured parameters was performed. All models were best described by a linear equation. An R2 value of 0.94, with a standard error of the estimate of 0.204, was obtained for menstrual age versus fetal foot length. When the model for fetal foot length and menstrual age was compared with published anatomical data, close agreement was seen over the time interval studied. Our results suggest that the measurement of fetal foot length with ultrasound gives a reliable assessment of anatomical fetal or neonatal foot length and is highly correlated to the menstrual age of the fetus.