Ultrasound screening of fetal structural abnormalities at 12 to 14 weeks in Hong Kong

OBJECTIVE: Ultrasound screening for fetal abnormalities is conventionally performed at 18 to 20 weeks of gestation. Recent data suggested that many fetal structural abnormalities could be detected by ultrasound examination at 12 to 14 weeks of pregnancy. In this study, we investigated the effectiveness of early ultrasound examination in the detection of fetal abnormalities in women aged 35 years or older. METHODS: From February 1998 to March 2001, pregnant women aged 35 or above were examined by transabdominal and transvaginal sonography between 12 and 14 weeks of gestation. If the anatomical survey was normal, the women underwent routine 16- to 20-week ultrasound examination. Pregnancy outcome was obtained from the hospital records or by contacting the subjects. RESULTS: Twenty-six of the 1609 fetuses had structural abnormalities. Fourteen were detected at the ultrasound examination at 12 to 14 weeks. Detection rate was 53.8% (14/26; 95% CI 44, 64) with a false-positive rate of 0.3% (5/1583; 95% CI 0.16, 0.44). Six additional abnormalities (23.1%, 6/26) were detected at 16- to 20-week ultrasound examination. The overall detection rate of structural abnormalities was 76.9% (20/26; 95% CI 68.6, 85.2). CONCLUSIONS: The effectiveness of ultrasound examination at 12 to 14 weeks to screen for fetal abnormalities approached that achieved at 20 weeks and can be a good adjunct to the conventional examination.     

Endovaginal sonographic diagnosis of the fetal urinary tract anomalies in early pregnancy

Transvaginal sonography has enhanced the ability to follow fetal development and detect pathologies in early gestation. Examination of the fetal urinary tract is an integral part of routine sonographic examinations in the second trimester of pregnancy and one of the major benefits of prenatal sonography is to allow early diagnosis of relatively common urinary tract malformations. Detailed evaluation of the fetal urinary tract and identification of anomalies were considered to be difficult before the 18th week of gestation prior to the use of transvaginal sonography. Using the transvaginal route, a detailed evaluation of the kidneys is possible around 12 weeks and structural anomalies of the urinary tract are being detected at an ever-increasing rate. Transvaginal sonography, owing to its proximity to the maternal pelvic organs, allows an earlier determination of the normal fetal urinary system and more accurate diagnosis and identification of fetal urinary anomalies as compared with transabdominal ultrasound. Received: 22 May 2000 / Accepted: 21 August 2000     

Transvaginal assessment of fetal anatomy at 11 to 16 weeks of gestation in relation to fetal position

OBJECTIVE: To investigate the ability of the high-frequency transvaginal scanning technique to assess embryo-fetal anatomy in early pregnancy in relation to fetal position and in comparison with transabdominal scan. METHODS: A study population of 1,402 pregnant women were examined by transvaginal ultrasonography performed at 10(+1) to 16(+0) weeks of pregnancy. At 14(+1) to 16(+0) weeks of gestation, an ultrasonographic examination was performed in 247 pregnant women by transvaginal and transabdominal route. The criteria necessary for an adequate visualization of fetal organs and structures were met. RESULTS: The visualization rate of complete fetal anatomy increased with increase in menstrual age and fetal position affected this possibility. A detailed brain anatomy was more easily viewed with the fetus in the cephalic or transverse position than in the breech position, whereas the thoracic and abdominal anatomy were viewed more easily with the transverse position compared to the cephalic or breech position. Complete surveys of fetal anatomy were possible in 50% and 62% of women with transabdominal scan and in 85% and 85% with transvaginal one at 15 and 16 weeks' gestation, respectively (p < 0.001). CONCLUSION: A detailed assessment of fetal structures was possible in most cases at 13 weeks of gestation. Fetal position can influence this capability. At 14(+1) to 15(+0) weeks' gestation more anatomical surveys were completed with a transvaginal scan compared to a transabdominal one and this was influenced by fetal position.     

Prenatal diagnosis in the first trimester of pregnancy

In the past 2 decades, the second trimester of pregnancy has been the most common time for prenatal diagnosis of fetal anomalies and chromosomal aneuploidies. More recently, screening for and diagnosis of chromosomal abnormalities are increasingly being performed in the first trimester. With improvements and technological advances in ultrasound, it is now possible to identify many fetal structural anomalies at 11 to 13 6/7 weeks' gestation. At 10 to 11 weeks' gestation, biochemical markers in serum-PAPP-A, free beta-hCG, AFP, and uE3-combined with sonographic measurement of nuchal translucency and the presence/absence of the nasal bone can achieve a Down syndrome detection rate of 97.5% at a false-positive rate of 5%. Structural anomalies of the central nervous system, and the cardiac, renal, and gastrointestinal tracts can now be diagnosed by either transabdominal or transvaginal scanning, achieving detection of up to 80% of CNS anomalies by 13 weeks' gestation. In future, the emphasis in prenatal diagnosis will likely be in the first trimester. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to explain the rationale for first trimester combined ultrasound and serum analyte screening for fetal Down syndrome, describe the fetal anatomic structures that can be seen and evaluated in the first trimester, provide patient counseling about the relative benefits of genetic amniocentesis versus chorionic villous sampling, and discuss the application of Doppler technology to the evaluation of a first trimester fetus.     

The value of sonography in early pregnancy for the detection of fetal abnormalities in an unselected population.

OBJECTIVE: To determine the value of early pregnancy sonography in detecting fetal abnormalities in an unselected obstetric population. DESIGN Prospective cross-sectional study. All women initially underwent transabdominal sonography and when the anatomical survey was considered to be incomplete, transvaginal sonography was also performed (20.1%). Nuchal translucency was measured and karyotyping was performed as appropriate. SETTING: University Department of Obstetrics and Gynaecology. PARTICIPANTS: 6634 sequential unselected women (mean maternal age 29.9 years, range 13-50; mean gestational age 12+4 weeks, range 11+0-14+6), carrying 6443 live fetuses participated in this study. MAIN OUTCOME MEASURE: Detection rate of fetal anomalies and the associated cost per case detected in early pregnancy. RESULTS: The incidence of anomalous fetuses was 1.4% (92/6443) including 43 chromosomal abnormalities. The detection rate for structural abnormalities was 59.0% (37/63, 95% CI 46.5-72.4) and the specificity was 99.9% in early pregnancy. When the first and second trimester scans were combined, the detection for structural abnormalities was 81.0% (51/63, 95% CI 67.7-89.2). Seventy-eight percent (31/40) of chromosomal abnormalities (excluding three cases of XXY) were diagnosed at 11-14 weeks, either because of a nuchal translucency greater than or equal to the 99th centile for gestational age (43%; 17/40, 95% CI 27.4-60.4), or due to the presence of structural abnormalities (35%; 14/40, 95% CI 21.2-52.8). Sixty-five percent (15/23) of cases of trisomy 21 were also diagnosed either because of having a nuchal translucency greater than or equal to the 99th centile (57.0%; 13/23) or due to the presence of a structural abnormality (9.0%; 2/23). Overall, the detection rate of structurally abnormal fetuses was 59% (37/63) in early pregnancy and 81% in combination with the second trimester scan. The cost per abnormality diagnosed in early pregnancy is estimated to be pound sterling 6258 per structurally abnormal fetus, pound sterling 7470 per chromosomal abnormality and pound sterling 4453 per anomalous fetus. CONCLUSION: The majority of fetal structural and chromosomal abnormalities can be detected by sonographic screening at 11-14 weeks, but the second trimester scan should not be abandoned.     

First- and second-trimester diagnosis of fetal ocular defects and associated anomalies: report of eight cases

Ocular cataract, hypertelorism, hypotelorism, anophthalmos, and microphthalmos are rare malformations commonly associated with other fetal anomalies. Previously, ocular malformations were detected only after mid-gestation. Transvaginal sonography allows the detection of many structural fetal anomalies. We describe the case reports of eight ocular anomalies among 1600 fetal screenings by transvaginal sonography at 12-18 weeks' gestation. Severe cataract was correctly diagnosed by transvaginal sonography. However, transvaginal sonography failed to detect moderate cataract in a case of repeat cataract in a subsequent gestation. Anophthalmia may sometimes be secondary to a degenerative process in middle and late pregnancy. In five of the eight described cases, the eye malformations were associated with defects of the central nervous system.     

Reference values of fetal orbital measurements by transvaginal scan in early pregnancy

OBJECTIVE: To construct reference ranges of orbital diameters, measured in early pregnancy by transvaginal sonography. METHODS: The study group consisted of 2717 fetuses of pregnant women referred to our center and examined by transvaginal ultrasound between 11-16 week's gestation. Nomograms with confidence intervals (5th and 95th percentile) for each orbital measurement (orbital diameter, interocular and binocular distance) versus gestational age were produced. RESULTS: The orbital measurements increased in a linear fashion throughout early pregnancy with a good correlation with gestational age. CONCLUSION: Transvaginal sonography is able to visualize and measure orbital diameters with accuracy in early pregnancy; reference ranges were developed that can be used to evaluate normal orbital development and can be helpful in the detection of syndromes with orbital growth defects and other associated fetal anomalies.     

Outcome of fetal cystic hygroma and experience of intrauterine treatment

OBJECTIVE: To review our cases of fetal cystic hygroma and to examine the prognostic factors with the goal of establishing criteria for the intrauterine treatment for cystic hygroma. PATIENTS AND METHODS: Thirty-one cases of fetal cystic hygroma were managed by us from January 1988 to December 1997, and 21 cases were available for analysis. Three prognostic factors, namely chromosomal abnormality, structural anomaly and hydrops fetalis, were evaluated. We treated 2 cases of cystic hygroma associated with hydrops fetalis in utero using OK-432 injection under ultrasound guidance. RESULTS: The fetuses without any of the prognostic factors listed above showed a good prognosis throughout the fetal and neonatal periods. However, in this group, 2 infants with large tumors died of hemorrhage from the tumor at 6 months and 3 years of age, respectively. Cases with hydrops fetalis without chromosomal abnormalities or structural anomalies (5 cases) resulted in either intrauterine fetal death (IUFD, 2 cases) or early perinatal neonatal death (early PND, 3 cases). The cause of early PND was circulatory failure. Most of the hydrops cases with either a chromosomal abnormality or structural anomaly resulted in IUFD before 22 weeks of gestation. The size of the cyst decreased in 1 of 2 cases treated in utero. CONCLUSIONS: The fetal cases of cystic hygroma showing hydrops fetalis without chromosomal abnormalities or structural anomalies are considered to be possible candidates for intrauterine therapy. Those with very large cystic hygroma without any of the three prognostic factors are also thought to be candidates for fetal treatment. Based on our clinical experience, sclerotherapy using OK-432 is considered to be a treatment option in selected cases with fetal cystic hygroma.     

Antenatal classification of hydrops fetalis.

Among 12,572 pregnant women referred for ultrasound examination from 1985-1990, 76 fetuses had ultrasonographic findings of hydrops fetalis, ten immune and 66 nonimmune. Fetuses with cystic hygroma (20), heart defects or arrhythmias (13), or other congenital anomalies (15) accounted for the majority of the nonimmune cases. Antenatal chromosomal studies were available in 42 fetuses with nonimmune hydrops, of which 14 (34%) were abnormal with seven monosomes and six trisomies. Seventeen cases of hydrops (22%) were classified as idiopathic because they had no recognizable etiology. It is concluded that: 1) The ultrasonographic incidence of fetal hydrops in referral centers can be as high as one in 165 pregnancies; 2) most cases of fetal hydrops are of the nonimmune type, which can occur in a low-risk population and can be detected with early second-trimester ultrasound screening; and 3) the complexity of this condition and the high rate of chromosomal abnormalities require referral to a high-risk center for evaluation and pregnancy management.     

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.     

Accuracy of clinical diagnostic methods of threatened abortion

OBJECTIVE: To examine the accuracy of clinical diagnostic methods in assessing vaginal bleeding in pregnant women before 28 weeks' gestation. METHODS: 772 consecutive women who presented with threatened abortion before 28 weeks' gestation were studied. Structured history and physical examination were performed on each woman as initial clinical assessment. This was followed by transvaginal sonography to determine the status of pregnancy. The accuracy of diagnoses at different clinical stages (history, physical examination, and transvaginal sonography) relative to the final diagnosis was compared using the kappa coefficient (kappa). RESULTS: Clinicians were unable to accurately diagnose or predict the status of the pregnancy from history alone (kappa = 0.33; 95% CI 0.28, 0.38) or after physical examination (kappa = 0.57; 95% CI 0.52, 0.62). Transvaginal sonography led to an accurate diagnosis of pregnancy status (kappa = 0.96; 95% CI 0.95, 0.98) in most cases, except where an ectopic pregnancy existed. Absence of abdominal tenderness (p = 0.04), cervical excitation (p = 0.02), and incorrect identification of retained products of conception on transvaginal sonography (p = 0.01) were features of missed ectopic pregnancy. CONCLUSIONS: The clinical assessment of threatened abortion by history and physical examination is unreliable in most cases. The diagnostic accuracy is improved by the addition of transvaginal sonography. Even with the help of transvaginal sonography, a small proportion of ectopic pregnancies will be missed.     

A characteristic cluster of fetal sonographic markers that are predictive of fetal Turner syndrome in early pregnancy

OBJECTIVE: The purpose of this study was to describe a characteristic cluster of sonographic features of fetuses with Turner syndrome in early pregnancy. STUDY DESIGN: A targeted transvaginal ultrasound examination of all fetal organs was performed for 40123 consecutive pregnant women at 14 to 16 weeks of gestation. Both low- and high-risk pregnancies were included. Fetal karyotyping was performed in 9348 cases. The main indications were major fetal anomalies, advanced maternal age, abnormal biochemical markers, maternal anxiety, and request. RESULTS: Turner syndrome was detected in 13 fetuses (0.03%, 1/3086 early pregnancies). Huge septated cystic hygroma, severe subcutaneous edema, and hydrops were observed in all cases. A short femur was detected in 12 of 13 fetuses. A narrow aortic arch was visualized in all 8 fetuses who were scanned after 1995, when scanning of the aortic arch became mandatory in our institution. Four other fetuses had three or four of the five markers, 2 of the fetuses had trisomy 21, 1 fetus was normal, and one case of missed abortion occurred without a karyotype. CONCLUSION: A reliable diagnosis of Turner syndrome by sonographic means is possible in early pregnancy.     

Three fetuses karyotyped as Turner syndrome with cystic hygroma developing hydrops: prognosis and outcome

INTRODUCTION: We present three cases of fetuses diagnosed as Turner syndrome with cystic hygroma (CH) developing hydrops to discuss the prenatal diagnostic and prognostic criteria of CH in ultrasound and outcome of the fetuses. CASES: The first case was 30-year-old pregnant woman with a nuchal translucency measurement of 8 mm at 12 weeks' gestation. Serial ultrasound examinations revealed non-septated cystic hygroma and hydrops. The pregnancy was terminated at the 18th week of gestation. Diagnosis of CH was made at 14 and 15 weeks of gestation in case 2 and case 3, respectively. Ultrasound revealed large cystic septated sacs in the nuchal area combined with serosal fluid collection and cutaneous edema. Spontaneous fetal demise occured at 21 and 16 weeks of gestation in cases 2 and 3, respectively. All fetuses were diagnosed as Turner syndrome.     

Patients with a prior failed transvaginal cerclage: a comparison of obstetric outcomes with either transabdominal or transvaginal cerclage

OBJECTIVE: Our purpose was to compare the incidence of preterm birth after a prior failed vaginal cerclage in patients who had a subsequent transabdominal or a transvaginal cerclage. STUDY DESIGN: We conducted a retrospective cohort study of singleton pregnancies in women who had undergone (9-14 weeks) either a transabdominal or a transvaginal prophylactic cerclage after >/=1 prior failed transvaginal cerclage. Prior failed transvaginal cerclage was defined as a preterm birth at <33 weeks' gestation in the immediate prior pregnancy despite a transvaginal cerclage. All transabdominal cerclage procedures were performed by a single attending physician (George Davis, DO). Patients with a cervix too short for transvaginal cerclage placement, placenta previa, or major fetal anomalies were excluded. Primary outcome was preterm birth at <35 weeks' gestation. RESULTS: Forty transabdominal and 24 transvaginal cerclage pregnancies were analyzed. These 2 groups were similar in race and payer status but differed in age (34.0 +/- 4.2 vs 31.3 +/- 4.6 years, respectively; P =.01). The transabdominal cerclage group had more prior failed cerclage procedures per patient (1.8 +/- 1.0 vs 1.1 +/- 0.3; P =.02) and more prior 14- to 24-week spontaneous abortions per patient (2.4 +/- 1.3 vs 1.5 +/- 1.0; P =.02) than the transvaginal cerclage group. Preterm delivery at both <35 and <33 weeks' gestation was less common in the transabdominal cerclage group (18% vs 42%, P =.04; 10% vs 38%, P =.01; respectively) than in the transvaginal cerclage group. Gestational age at delivery was 36. 3 +/- 4.1 weeks in the transabdominal cerclage group and 32.8 +/- 8. 6 weeks in the transvaginal cerclage group (P =.03). Preterm premature rupture of membranes also occurred less often in the transabdominal cerclage group than in the transvaginal cerclage group (8% vs 29%, P =.03). CONCLUSION: In patients with a prior failed transvaginal cerclage, transabdominal cerclage is associated with a lower incidence of preterm delivery and preterm premature rupture of membranes in comparison with transvaginal cerclage.     

First trimester ultrasonographic diagnosis of fetal structural abnormalities in a low risk population

Objectives Ultrasonographic screening between 12⁺⁰¹ and 13⁺⁶ weeks for fetal structural abnormalities using transab dominal sonography and, where necessary, transvaginal sonography in a low risk population.
Design A prospective observational study
Setting London teaching hospital
Methods Pregnant women with a total of 1632 low risk viable fetuses between 12⁺⁰ and 13⁺⁶ weeks of gestation were scanned using transabdominal and, where necessary, transvaginal sonography (40%). If the anatomical survey was normal, the women underwent routine 18-20 week anomaly scans. Pregnancy outcomes were obtained from radiological and neonatal computerised databases, and postal or telephone patient enquiry.
Results Seventeen (1.0%) major structural abnormalities were diagnosed in the study group. Of these, 11 (64.7%) were diagnosed at the 12-13 week scan, three diagnosed in the mid-trimester and three postnatally. Of the fetal abnormalities diagnosed antenatally, 78.6% were diagnosed in the first trimester. The sensitivity of abnormality detection by the combination of both first and second trimester scans was 82.3%. In addition, a significant number of missed abortions (   n = 36  ) were also diagnosed by the first trimester scan.
Conclusion This study has demonstrated the potential of screening a low risk population for fetal abnormalities at 12-13 weeks of gestation using transabdominal sonography and, where necessary, transvaginal sonography. Larger studies are required to establish the clinical value of the first trimester scan.     

Amniotic fluid alpha-fetoprotein and acetylcholinesterase in early genetic amniocentesis

Early identification of fetal abnormalities is possible as a result of improved ultrasound resolution, chorionic villus sampling, and early genetic amniocentesis. A potential advantage of early genetic amniocentesis over chorionic villus sampling is its ability to detect neural tube defects. We obtained 476 amniotic fluid samples between ten and 15 weeks' gestation and analyzed them for karyotype and alpha-fetoprotein (AFP); 142 were also tested for acetylcholinesterase. Amniotic fluid AFP levels rose to a peak at 12-13 weeks' gestation and then gradually declined, closely approximating the pattern in fetal blood. The rate of inconclusive acetylcholinesterase results (a faint but true band) was four times higher than that later in pregnancy (10.6 versus 2.46%, respectively). However, the rate of associated fetal congenital anomalies was lower than that later in pregnancy. Chromosomal abnormalities were detected in the study group, and the association with low amniotic fluid AFP in early genetic amniocentesis levels was identical to that further along in pregnancy. These data help establish normal values for AFP in early pregnancy. With AFP and cautious interpretation of acetylcholinesterase, early genetic amniocentesis can be used for neural tube defect detection.     

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.     

Efficacy of first trimester transvaginal sonography in detecting normal fetal development.

The transvaginal probe is now commonly used by the obstetrician/gynecologist. The improved resolution offered by the probe makes it easier to study the anatomic development of the first trimester fetus in greater detail. The aim of this study was to define the gestational age at which certain fetal structures become apparent by ultrasound and to screen pregnancies at high risk for development of fetal anomalies that could be detected in the first trimester. Endovaginal ultrasound was performed on 60 pregnant women at 8 to 13 menstrual weeks. Clinical follow-up disclosed 36 normally developed fetuses at delivery, five abnormal scans, and 19 ongoing pregnancies. The results of this study show that it is possible to demonstrate most of the major fetal structures by 13 weeks' gestation. By imaging the fetus transvaginally, detection of fetal anomalies can be accomplished much earlier than with the transabdominal scanning alone.     

The early development of the fetal kidney-an in utero sonographic evaluation between 13 and 22 weeks' gestation

OBJECTIVES: To establish a nomogram for early fetal kidney development during early gestation. METHODS: The study is a prospective, cross-sectional evaluation of 275 male and female fetuses between 13 and 22 weeks in normal singleton pregnancies. Measurements of fetal kidney length were performed by high resolution transvaginal ultrasonography between 14 and 17 weeks' gestation, and by transabdominal ultrasonography beyond 18 weeks' gestation. RESULTS: Adequate kidney length measurements were obtained in all 275 normal fetuses as well as in six fetuses with urinary tract anomalies. Kidney length as a function of gestational age was expressed by the regression equation: (square root) kidney length (mm) = -11.66 + 1.52 x gestational age (weeks). The correlation coefficient, r = 0.983 was found to be highly statistically significant (p < 0.0001). The normal mean and the 90% prediction limits were defined. Four cases with single kidney and two cases with posterior urethral valve had kidney length above the 95% upper limit. CONCLUSION: The present data offer a normal range of fetal kidney length from early stages of gestation that may allow intrauterine assessment of its development. It may also be helpful in the early prenatal diagnosis of renal abnormalities.