Usefulness of fetal echocardiography in the prenatal diagnosis of Down syndrome based on material from the Department for Diagnosis of Congenital Malformation's of the Institute "Polish Mother's Memorial Hospital' in Lodz between 1994-1999. Part I

Between 1994-1999 at the Department for Diagnosis of Congenital Malformations at the PPMH Institute there were ultrasound and echocardiography examinations performed in 40 fetuses with Down Syndrome. In our study most of the cases come from low risk groups of pregnant women. Congenital heart defects (AV-canal in 13/18 cases) were the most common anomalies diagnosed prenatally in fetuses with Down Syndrome. In fetuses with DS, functional cardiac anomalies with normal heart anatomy were recorded: disproportion and hypertrophy in 4/12 cases, tricuspid valve regurgitation, bright spot and pericardial effusion in 3/12 cases. The aim of our study was a retrospective analysis of fetuses with DS, which were diagnosed at the Department for Diagnosis of Congenital at the Institute of "PMMH" in 1994-1999 years.     

Usefulness of fetal echocardiography in the prenatal diagnosis of Down syndrome based on material from the Department for Diagnosis of Congenital Malformation's of the Institute "Polish Mother's Memorial Hospital' in Lodz between 1994-1999. Part II

In the years 1994-1999 at the Department for Diagnosis of Congenital Malformations at the PPMH Institute, there were ultrasound and echocardiography examinations performed in 40 foetuses with Down Syndrome. In our study most of the cases come from low risk groups of pregnant women. Extracardiac malformations were diagnosed prenatally in 25% fetuses with Down Syndrome. The most common anomaly from extracardiac malformations was duodenal atresia (13/40 cases--32.5%).     

Clinical implication of isolated right dominant heart in the fetus

OBJECTIVE: To evaluate the clinical implication of isolated right dominant heart (RDH) in fetal echocardiography. STUDY DESIGN: We reviewed the medical records of pregnant women diagnosed with fetal RDH at Asan Medical Center from December 1999 to December 2005. The criteria of RDH were the ratio of right-to-left atrial and ventricular width and the ratio of the diameter of pulmonary artery-to-aorta were greater than 1.5. Fetuses with congenital heart disease, including coarctation of the aorta (CoA), noncardiac anomalies or chromosomal abnormalities were excluded. RESULTS: RDH was identified in 44 fetuses. Twenty-nine (66%) were confirmed to have normal heart and 15 (34%) had cardiac anomalies by postnatal echocardiogrphy; 11 CoA, 1 interruption of aortic arch, 1 patent ductus arteriosus, and 2 ventricular septal defect. Mean gestational age at presentation with RDH was later in normal fetuses as compared to fetuses with CoA (p < 0.005). Only 26% (4/15) of fetuses presenting with RDH during the second-trimester were found to have normal heart postnatally, compared with 86% (25/29) of those diagnosed in the third-trimester. CONCLUSION: RDH in the fetus is a risk factor for postnatal CoA particularly when diagnosed in the second-trimester, and should be an indication for neonatal echocardiography.     

22q11 deletions in fetuses with malformations of the outflow tracts or interruption of the aortic arch: impact of additional ultrasound signs

OBJECTIVES: One hundred and forty-one consecutive cases of malformations of the outflow tracts or interrupted aortic arch (IAA), detected by fetal echocardiography, underwent detailed anatomy scan, karyotyping and fluorescence in situ hybridization analysis (FISH) to detect the prevalence of 22q11 microdeletion and to evaluate neonatal clinical findings and outcome according to the presence of the genetic defect. Then, we sought to investigate whether some prenatal ultrasound findings could help identify fetuses at higher risk of carrying the 22q11 microdeletion. METHODS: Echocardiography and FISH for the DiGeorge critical region (22q11) were performed in all cases. RESULTS: 22q11 microdeletion was detected in 28 of 141 fetuses (19.8%). Intrauterine growth restriction (IUGR) appeared to be associated with the worst prognosis, being present in 2/2 intrauterine fetal deaths and 5/6 post-natal deaths. IUGR, additional aortic arch anomalies and thymic hypo/aplasia were significantly more frequent in fetuses with 22q11 microdeletion (p=0.011, 0.011 and <0.0001, respectively). Prenatal ultrasound thymus examination, performed on the last 84 fetuses, showed 75% sensitivity and 94% specificity. The combination of 2 predictors, namely, thymus defects and IUGR associated with additional aortic arch anomalies reached more than 90% sensitivity and 100% specificity. CONCLUSIONS: Our study demonstrates that 22q11 microdeletion occurs in 20% of malformations of the outflow tracts and IAA type B, as detected in utero, and that this association is significantly predicted by the presence of associated ultrasound findings: thymic hypo/aplasia, IUGR and additional aortic arch anomalies. The feasibility of a correct prenatal diagnosis should enable clinicians to provide the couple with further informative counselling and to plan adequate post-natal medical interventions.     

Fetal echocardiography in fetal ovarian cysts

OBJECTIVES: The aim of the study was to evaluate the outcome of fetuses with ovarian cysts in relation to fetal echocardiography. MATERIAL AND METHODS: In the Department for Diagnosis and Prophylaxis of Birth Defects at the Polish Mother's Memorial Hospital in Lodz fetal echocardiography was performed in 21 fetuses with ovarian cysts between the years 1995-2006. OUTCOMES: In 18 out of 21 (86%) fetuses we have found normal heart anatomy (NHA) and in 3 fetuses congenital heart defect (CHD). In 7 out of 18 (39%) fetuses with NHA there were functional anomalies, including 5 fetuses with hypertrophy Four neonates with hypertrophy required surgical procedures after the delivery. Prenatal hypertrophy was not observed in case of only one neonate which was operated after the delivery. CONCLUSIONS: 1. Fetal echocardiography studies were very often abnormal in fetus with ovarian cysts (mainly as functional anomalies). 2. Functional anomalies detected in fetal echocardiography more often resulted in surgical procedures after the birth, whereas normal heart study was more often connected with spontaneous regression of ovarian cyst (p=0.0265).     

The role of fetal echocardiography and genetic sonography in prenatal diagnosis of the Edward's syndrome--analysis of the thirty case diagnosed at the Department of the Diagnosis for Fetal Malformations at the Institute "Polish Mother's Memorial Hospital."

OBJECTIVE: Trisomy 18 (Edward's syndrome) is one of the most common chromosomal aberration in fetuses/neonates. The aim of our study was to assess the usefulness of the fetal echocardiography and genetic sonography in prenatal diagnosis trisomy 18 (retrospective analysis). MATERIAL AND METHOD: Between 1994-2000 at the Institute "Polish Mother's Memorial Hospital" 30 cases of trisomy 18 were diagnosed. RESULTS: Every fetus/neonate presented with congenital anomalies. The most common were: intrauterine growth retardation (96%) and congenital heart defects (92%). CONCLUSIONS: Retrospective analysis indicates the great role of "genetic sonography" and fetal echocardiography in prenatal diagnosis of trisomy 18.     

Non-immune hydrops fetalis--prognostic factors based on fetal echo (analysis in 230 cases)

OBJECTIVES: The aim of the research was to assess whether all reasons of NIHF were leading to the same poor outcome. MATERIALS AND METHODS: The material of the research study consisted of 192 fetuses with follow up from 230 fetuses with NIHF who had echocardiography and detailed sonography between 1992 and 2002. RESULTS: The most common anomalies associated with NIHF were cardiological anomalies n = 71 (30.8). The remain extracardiac causes of NIHF were: so called "other structural defects" n = 24 (10.4%), infections (without myocarditis) n = 24 (10.4%), multiple structural defects n = 20 (8.7%), urogenital defects n = 17 (7.4%), pulmonary anomalies n = 17 (7.4%), gastrointestinal anomalies n = 12 (5.2%), chromosomal defects n = 8 (3.5%), mirror syndrome n = 2 (0.9%) and idiopathic n = 35 (15.3%). In the group of NIHF 102 fetuses (44.3%) presented echocardiographic signs of congestive heart failure which statistically increased mortality ratio. In the group of fetuses with NIHF follow up was established in 192 (83.4%) fetuses/newborns; there were n = 139 (72.4%) demise and n = 53 (27.6%) alive. Therapy in utero was applied to 28 cases. In this group 13 fetuses/newborns (46.4%) survived. CONCLUSIONS: Multiple structural anomalies and cardiological anomalies causing NIHF are connected with poor prognosis for fetus or neonate. Congestive heart failure coexisting with NIHF (in our series in about 44%) significantly increased mortality ratio what point the special role of fetal echocardiography. Relatively better prognosis was observed possible in cases with NIHF without structural anomalies and mild intensify or due to infection but without cardiac anomalies. In selected fetuses therapy in utero may increase the survival ratio.     

Chromosomal and cardiac anomalies in fetuses with intracardiac echogenic foci.

OBJECTIVE: To evaluate the prevalence of intracardiac echogenic foci (ICEF) and the association between ICEF and chromosomal and cardiac anomalies in Brazilian women. METHODS: In a cross-sectional observational study, 373 of the 23,360 genetic sonograms performed at a private maternal-fetal medicine clinic over 5 years showed intracardiac echogenic foci (ICEF). These 373 sonograms were reviewed for chromosomal and cardiac anomalies and associations were analyzed using the chi(2) test or the Fisher exact test. P<0.05 was considered significant. RESULTS: The prevalence of ICEF was 1.7%. Cardiac anomalies were detected in 10 sonograms (2.7%) and chromosomal anomalies in 14 (3.7%). There were cardiac defects in 6 (1.7%) of the 359 euploid fetuses with isolated ICEF. Of the 373 women who had fetuses with ICEF, 295 were younger than 35 years and 78 were 35 years or older. There were 6 fetuses (2.1%) with aneuploidy in the younger group and 8 (10.3%) in the older group. CONCLUSION: The prevalence of ICEF was 1.7%, and there was an association between cardiac and chromosomal anomalies. Women carrying fetuses with ICEF should be offered fetal echocardiography and karyotyping.     

胎儿心脏锥干畸形产前诊断评价

目的评价胎儿心脏锥干畸形产前超声心动图诊断准确性。方法运用胎儿超声心动图进行先天性心脏病产前诊断，并与心脏病理诊断或新生儿心脏超声诊断进行比较分析。结果2063例胎儿进行心脏超声检查，产前发现胎儿心脏锥干畸形28例，诊断时平均孕周26．6周（16～40周），产前诊断包括大血管转位5例，法洛四联症5例，右室双出口6例，永存动脉干9例，室间隔缺损合并主动脉骑跨可能1例，2例检查发现大血管位置异常但胎儿超声心动图未予明确诊断。24例经胎儿心脏病理检查或新生儿心脏超声检查确诊，4例失访（包括1例TOF／TA？，2例“大血管发育异常”，1例TGA）。比较产前诊断与产后诊断，分析大血管位置关系诊断准确性为75．0％（18／24）。结论胎儿超声心动图可正确诊断胎儿心脏锥干畸形，需运用多种超声切面及彩色脉冲多普勒确定大血管位置关系。     

Assessment of fetal circulation in the late first trimester--preliminary study

OBJECTIVES: to confirm that fetal echocardiography is indeed possible in late first trimester and that it improves the standard of the so-called "genetic" ultrasound scan. MATERIAL AND METHODS: Early echocardiography was performed in 75 fetuses from high and low risk pregnancies. All fetuses underwent echocardiography examination in 18-22 weeks of gestation and established follow up. RESULTS: The most suitable method of visualization seems to be transabdominal examination, between 13.0-13.6 weeks of gestation, an transvaginal one, between 12.0-12.6 weeks of gestation, with 90% effectiveness. In researched group of 75 fetuses (with established follow up) there were four heart defects (5.3%). Three of them were diagnosed before 14th week of gestation. One case (tetralogy of Fallot) was overlooked. There were two false positive diagnosis verified at 20th week of gestation. CONCLUSIONS: Early echocardiography, especially between 12.0-13.6 weeks of gestation, is a possible and valuable method of diagnosis. Reference evaluation should be performed between 18 and 22 weeks of gestation. In cases with suspected anomalies karyotyping is recommended. Congenital heart disease diagnosed at late first trimester should be treated as the next potential marker of genetic disorder.     

Intracytoplasmic sperm injection in infertile patients with structural cytogenetic abnormalities.

OBJECTIVE: To investigate the incidence of chromosomal aberration in men and women in an intracytoplasmic sperm injection (ICSI) program for severe male infertility as well as in conceptuses resulting from these ICSI treatments. STUDY DESIGN: We evaluated chromosomal analysis, outcome of ICSI and the conceptuses resulting from treatment of 301 couples included in ICSI program. RESULTS: Cytogenetic evaluation demonstrated structural anomalies in 11 cases (3.6%), 9 men (2.9%) and 2 women (0.7%), all consisting of balanced chromosomal translocations. There were no significant differences in the rates of developed embryos (44.2% versus 40.1%) in couples with abnormal (n = 11) and normal (n = 290) chromosomal analysis. Embryo transfer led to a similar number of newborns (15.3% versus 12.4%) per transferred embryos, without any correlation with parents' chromosomes. In 63 fetuses conceived from couples without chromosomal abnormalities, we observed one fetus affected by Patau syndrome (47,XY, + 13). Two of four (50%) fetuses conceived by couples with male balanced chromosomal defects were carriers of the chromosomal translocation inherited from their fathers. The two fetuses resulted in the birth of two infants observed to be normal at the 12-month pediatric follow-up. CONCLUSION: The offer of this treatment to infertile couples with male factor infertility should be accompanied by proper information regarding the genetic risks of this treatment. ICSI remains a good therapeutic option for infertile patients, but prenatal diagnosis is mandatory because of the potential increased aneusomic risk for the offspring conceived.     

Diagnosis and prognosis in double-outlet right ventricle

The aim of this study was to examine prenatal diagnosis of double-outlet right ventricle (DORV)-associated anomalies and prognosis of each case. Medical records were reviewed of fetuses with DORV who had fetal echocardiography at our institution from 2002 to 2006. Pre- and postnatal diagnosis and outcome were compared and evaluated. Twenty-one fetuses were diagnosed with DORV. The pregnancy was terminated in seven cases. Three cases had chromosomal abnormalities; three cases, hypoplastic left ventricle; and one case, encephalocele. Accurate prenatal diagnosis of the ventricular septal defect, outflow obstruction, and great artery relationship was achieved in 14 of 16 cases (87.5%). Only 2 of 13 live-born cases survived beyond 6 months. The overall prognosis for fetuses with DORV is poor. DORV is found in fetuses with a huge spectrum of associated cardiac and extracardiac anomalies. Careful assessment by fetal echocardiography can determine important anatomic details with adequate correctness for precise counseling.     

Prenatal sonographic findings in 207 fetuses with trisomy 21

OBJECTIVE: The objective was to evaluate the contribution of second trimester ultrasound examination to the prenatal diagnosis of trisomy 21 in 207 fetuses with this aneuploidy. The type and frequency of abnormal sonographic findings were determined. Possible multiple malformation patterns, characteristic of trisomy 21 were sought. STUDY DESIGN: Singleton fetuses that had prenatal sonography during the second trimester, then underwent cytogenetic evaluation in our institution, made up the study population. The sonographic findings of 207 fetuses with trisomy 21 were analyzed. RESULTS: Between 1990 and 2004, fetal karyotyping was performed in 22,150 patients for different indications. An abnormal karyotype was diagnosed in 514 cases (2.3%); among them 207 fetuses with trisomy 21 were detected (40.3%). Abnormal sonography was seen in 63.8% of the cases. Structural anomalies were detected in 28.5% of the trisomy 21 fetuses, among them cardiac defects (15.9%), central nervous system anomalies (14.5%), and cystic hygromas (6.8%) were the most common. Of the minor markers, increased nuchal translucency (28%), pyelectasis (20.3%), and shorter extremities (8.7%) were common findings. CONCLUSIONS: Appropriate diagnosis of structural anomalies, looking for relatively easily detectable minor markers and incorporating fetal echocardiography into the second trimester sonographic protocol, may increase the contribution of mid-trimester ultrasound examination to diagnosing trisomy 21.     

Antenatal prediction of pulmonary hypoplasia by acceleration time/ejection time ratio of fetal pulmonary arteries by Doppler blood flow velocimetry

OBJECTIVE: The purpose of this study was to develop a new method for the antenatal prediction of pulmonary hypoplasia by Doppler blood flow velocimetry. STUDY DESIGN: One hundred seventy-seven fetuses (160 normal fetuses and 17 fetuses with congenital anomalies that may affect fetal lung growth and/or development) were studied. Blood flow waveforms at the main branches of the pulmonary arteries were recorded by Doppler echocardiography from 20 to 39 weeks of gestation. The ratio of acceleration time to ejection time was calculated from the waveform as a parameter to predict pulmonary hypoplasia. RESULTS: Doppler waveform of normal fetal pulmonary artery showed a "spike-and-dome" pattern. The normal values of acceleration time/ejection time ratio from the right and left pulmonary arteries were 0.17 +/- 0.04 and 0.15 +/- 0.04, respectively. These values were not significantly altered through the gestational age observed in this study. The acceleration time/ejection time ratio of either right or left pulmonary artery was measured successfully in all cases of fetal congenital anomalies. In 8 of 17 fetuses, acceleration time/ejection time ratio was measured at both of the pulmonary arteries. Because of a congenital anomaly that affected the fetal lung or thorax asymmetrically (as in congenital diaphragmatic hernia or congenital cystic adenomatoid malformations of the lung), the acceleration time/ejection time ratio of both of the pulmonary arteries could be measured in only 5 of 13 fetuses. The technical difficulties for the measurement always existed in the affected side. Eleven of the 17 fetuses with congenital anomalies survived without signs of clinical pulmonary hypoplasia or persistent pulmonary hypertension of the newborn infant. The fetuses revealed normal acceleration time/ejection time ratio from at least one pulmonary artery. The remaining 6 fetuses died of pulmonary hypoplasia, and the diagnosis was confirmed by autopsy or clinical findings. Of those 6 fetuses, 5 fetuses demonstrated the acceleration time/ejection time ratio below normal in one side, and the ratio could not be obtained on the other side; 1 fetus showed the acceleration time/ejection time ratio below the normal range in both sides. CONCLUSION: The acceleration time/ejection time ratio by Doppler velocimetry that was obtained at the main branches of fetal pulmonary artery was consistent throughout gestational age from 20 to 39 weeks. This ratio appears to be an accurate parameter with which to predict the subsequent development of pulmonary hypoplasia and clinical outcomes of the newborn infants with high positive and negative predictive values (positive predictive value, 100%; negative predictive value, 100%).     

Conotruncal anomalies in fetal life: Accuracy of diagnosis, associated defects and outcome

Objectives

To assess the accuracy of prenatal echocardiography, associated anomalies, and outcome of fetuses with conotruncal anomalies (CTA).

Study design

We searched our database for CTA prenatally diagnosed between 1990 and 2005. We included tetralogy of Fallot (TOF), transposition of the great arteries (TGA), double-outlet right ventricle (DORV), truncus arteriosus (TA), pulmonary atresia with ventricular septal defect (PA-VSD) and posterior malalignment type VSD with aortic arch obstruction (pmtVSD-AAO). Data of 144 fetuses with complete follow-up were retrieved and analyzed.

Results

The main reason for referral was suspected heart defect on a routine obstetric scan (72%). Most cases were detected ≤22 weeks (55%). The presence of a CTA was confirmed postnatally in 143 cases (99%), and the diagnosis of the first fetal echocardiography was correct in 126 (87.5%). Most diagnosis of TOF (33/36, 91.7%), TGA (34/38, 89.5%) and DORV (34/38, 89.5%) were proved correct. Inadequate assessment of the interventricular septum, the distal aortic arch and/or the severity of the right outflow tract obstruction accounted for most errors. The accuracy rate was lower in TA (11/14, 78.6%) and PA-VSD (4/7, 57.1%), with evaluation of the branch pulmonary arteries as the main source of discrepancies. In 7/18 incorrect cases subsequent scans allowed to obtain a correct diagnosis. Most fetuses (64%) had an isolated CTA. Thirty-seven had chromosomal anomalies (26%) but none were found in TGA. 22q11 deletion affected 8.7% of the tested patients. Nuchal translucency (NT) was above 95th centile in 19/104 cases (18%) in which NT were measured. Fifty cases were interrupted. The overall one-year survival rate was 71%, with differences between cases with and without associated defects (9/25, 36% vs. 57/68, 83.8%; p < 0.01). The uncomplicated forms of TGA and TOF had the best survival rates (100%).

Conclusions

Most CTA can be diagnosed by fetal echocardiography with a high degree of accuracy. Chromosomal defects should always be ruled out, except for simple TGA. Current survival figures in many isolated CTA, especially simple TGA and TOF, support a change in the “classical” concept that congenital heart defects detected prenatally often have the worst outlook.

Condensation

Most CTA can be diagnosed by fetal echocardiography with a high degree of accuracy. Isolated CTA are more common and most of these may have a favourable outcome.     

Ultrasound diagnosis of fetal abnormalities and cytogenetic evaluation.

Over a 6 1/2 year period, in 288 pregnancies a variety of fetal malformations were detected by ultrasound. Two hundred and ten fetuses (73 per cent) were karyotyped. Gestational age at detection ranged from 11 to 38 weeks. The incidence of an abnormal karyotype in the total series was 14 per cent and 14.7 per cent in the 210 pregnancies in which a karyotype was performed. Single structural anomalies were found in 149 cytogenetically investigated fetuses, of which 25 had a chromosomal abnormality (17 per cent). Multiple structural malformations were present in 61 fetuses, of which 16 had an abnormal karyotype (26 per cent). Trisomy 18 was the most frequent finding. The most constant ultrasound finding in cases of an abnormal karyotype was polyhydramnios and severe IUGR in combination with structural defects. There is a need for extensive detailed ultrasound examination in high-risk pregnancies.     

Routine screening with fetal echocardiography for prenatal diagnosis of congenital heart disease

Congenital cardiac anomalies are the most common congenital anomalies, occurring in approximately eight of 1000 live births. Proper perinatal and neonatal management is dependent upon accurate prenatal diagnosis. Approximately 10% of fetuses with cardiac abnormalities have identified risk factors; hence, most of the anomalies occur in pregnancies without prenatal risk factors. The application of detailed fetal echocardiography for prenatal screening, at present reserved mainly for high-risk cases, requires further evaluation before being recommended for the general population.

This article presents our experience of evaluating the accuracy of fetal echocardiography as a screening method in detecting cardiac anomalies in the general population of Singapore. We reviewed data from 39 808 pregnant women who received antenatal care at the National University Hospital, Singapore, between January 1986 and December 1994, and who underwent routine fetal echocardiography at 21-22 weeks of gestation. We identified 294 cases of congenital heart defects by fetal echocardiography. We obtained a sensitivity of 85.4% for the detection of congenital heart disease, and a specificity of 99.9% to rule out such anomalies. Our positive and negative predictive rates were 87.7% and 99.9%, respectively.

We recommend routine screening by echocardiography of all pregnancies at 21-22 weeks of gestation, irrespective of risk stratifcation, for the prenatal detection of cardiac anomalies, in order to improve perinatal management.     

Cardiac defects in chromosomally normal fetuses with increased nuchal translucency at 10–14 weeks of gestation

Objective: To examine the prevalence, distribution and spectrum of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness. Patients and methods: During a 4-year period, targeted fetal echocardiography was used in 353 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks' gestation. The cardiac scan was performed at 18-22 weeks. In the last 138 cases enrolled, an additional scan at 12-16 weeks was carried out. The follow-up included the findings at necropsy or in the pediatric examination. A complete follow-up was achieved in 97%. Results: Cardiac defects were present in 32 (9.1%) cases, increasing from 5.3% in those with a nuchal translucency thickness of ≥ 95th centile (3.9 mm) to 24% when thickness ≥ 6 mm (p < 0.001). In 31 cases (97%), the cardiac defect was diagnosed antenatally; in 24 cases (77%) this diagnosis was confirmed later. In the remaining seven cases, the autopsy examination was not available. A wide range of cardiac defects was observed, with the most common being atrioventricular septal defect and tricuspid atresia. Conclusions: Euploid fetuses with increased nuchal translucency thickness have a significantly increased risk of cardiac defects. This is a marker of different types of heart anomalies and constitutes an additional indication for targeted fetal echocardiography. Most of the cardiac defects can be detected by fetal echocardiography.     

Teratogenic and embryocidal effects of Zidovudine (AZT) in sprague-dawley rats

Objective: The purpose of the present investigation was to analyze the effets of zidovudine on the postimplantation embryo and fetus.Methods: Pregnant Sprague-Dawley rats were given various doses (10 mg/kg, 30 mg/kg, 150 mg/kg) of zidovudine or saline by an endotracheal tube during the period of embryogenesis (days 6-8, 9-11, 6-11 postconception). The animals were sacrificed on days 18-19 of pregnancy, and their fetuses were removed by hysterotomy. Autopsies under low (15x) and high (40x) power light microscopy were performed on all fetuses.Results: There was no statistically significant difference among the groups with respect to maternal weight gain. There were more pregnancy resorptions in the group receiving high-dose zidovudine (150 mg/kg/day) throughout embryogenesis than in the control group (P = 0.001, respectively). Four major structural anomalies were noted among the 689 fetuses examined, but zidovudine was not associated with an increased frequency of congenital anomalies in rats when it was administered in doses similar to, 3-, and 15-fold higher than the regimen recommended for adult humans. The drug, however, was embryocidal in the high-dose group (P = 0.002).Conclusions: These findings are consistent with previous studies of preimplantation mouse embryos that demonstrated an embryocidal effect on preimplantation conceptuses. In summary, post-implantation embryonic zidovudine exposure was associated with significantly increased pregnancy losses (resorptions and intrauterine deaths).     

Fetal echocardiography: accuracy and limitations in a population at high and low risk for heart defects.

OBJECTIVE: Our objective was to assess the accuracy of prenatal echocardiography in detecting congenital heart defects in patients at high and low risk for structural cardiac anomalies. STUDY DESIGN: Sixty-nine consecutive fetuses with congenital heart defects who had had prenatal ultrasonography at greater than or equal to 18 weeks' gestation were evaluated to determine the accuracy of prenatal ultrasonography in identifying structural cardiac defects. Thirty-nine patients were at high risk and 30 patients were at low risk for cardiac anomalies. All fetuses were scanned with standard four-chamber and outflow tract views. Data concerning extracardiac anomalies and karyotypic abnormalities were tabulated. The accuracy of the four-chamber view alone in identifying congenital heart defects was evaluated. RESULTS: Fifty-seven of 69 fetuses (83%) were prenatally identified ultrasonographically as having a heart defect. There was no difference in the sensitivity of detecting cardiac anomalies between high-risk and low-risk groups. When the four-chamber view was used, only 63% of fetuses were recognized as having an abnormal heart. Extracardiac anomalies were noted in 36% and karyotypic abnormalities in 17% of patients. CONCLUSION: The four-chamber and outflow tract views done routinely in an ultrasonography laboratory seeing a mixed population of patients was successful in detecting 83% of fetuses with structural cardiac malformations. Because 43% of the fetuses with heart defects were referred for low-risk indications, systematic ultrasonographic examination of the fetal heart should not be reserved only for those at high risk.