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MINISTRY OF EDUCATION AND TRAINING MINISTRY OF HEATH HANOI MEDICAL UNIVERSITY BUI HAI NAM RESEARCH ON PRENATAL DIAGNOSIS IN COMMON CONGENITAL HEART DEFECTS Specialism: Obstetrics and Gynecology Code: 9720105 ABSTRACT OF THESIS HA NOI – 2023 The thesis has been completed at HANOI MEDICAL UNIVERSITY Supervisors: Assoc.Prof Tran Danh Cuong Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be present in front of board of university examiner and reviewer lever at… on ….2023 This thesis can be found at: National Library Library of Hanoi Medical University THE LIST OF WORKS HAS PUBLISHED AND RELATED TO THE THESIS Bui Hai Nam and Tran Danh Cuong (2018), “Chromosome abnormalities in fetuses with congenital heart defects” Journal of Obstetrics and Gynecology 16 (1), pages 52 - 57 Bui Hai Nam, Tran Danh Cuong, and Nguyen Thi Hiep Tuyet (2018), “Prenatal diagnosis of ventricular septal defects.” Vietnam Medical Journal, special issue celebrating 50 years of establishment of Vietnam Morphological Association 19682018, volume 496, pages 397-402 Bui Hai Nam, Tran Danh Cuong, Nguyen Thi Hiep Tuyet and Nguyen Hai Long (2019), “Prenatal diagnosis of chromosomal abnormalities in fetuses with tetralogy of Fallot” Journal of Obstetrics and Gynecology 16 (4), pages -10 Bui Hai Nam, Tran Danh Cuong, and Nguyen Thi Hiep Tuyet (2020) “Pre-diagnosis of chromosomal abnormalities in fetuses with congenital heart disease is related to the process of constriction of the heart cone-arteriosclerosis” Journal of Obstetrics and Gynecology 18 (2), pages 9-14 Bui Hai Nam, Tran Danh Cuong, and Nguyen Thi Hiep Tuyet (2022) “Prenatal diagnosis of chromosomal abnormalities in fetuses with congenital heart defects” Vietnam Medical Journal, September issue, volume 518, pp 179-184 INTRODUCTION Congenital heart defects are abnormalities in the heart structure and large blood vessels that appear during pregnancy in the 2nd - 3rd month of pregnancy There is a rate of 4-14/1000 live births Congenital heart defects are the leading cause of infant mortality, and many cases of congenital heart defects are operable with good outcomes According to Luu Thi Hong (2008), children with congenital heart defects accounted for 7.04% of the total number of children with birth defects, Phan Quang Anh (2010) had 25 cases of congenital heart defects genetically tested There are 12 cases with chromosomal abnormalities, according to Dykes (2016), about 1218% of children with congenital heart defects have chromosomal abnormalities Most babies born with congenital heart defects not have other birth defects, if the congenital heart defect is combined with other abnormalities that are often present in chromosomal abnormalities Therefore, the cases of congenital heart defects with chromosomal abnormalities are very difficult to predict after birth The prevalence of chromosomal abnormalities is up to 18-22% in all congenital heart defects, most of which are Trisomy 21 (Down syndrome), Trisomy 18 (Edward syndrome) and microdeletion syndrome 22q11.2 (DiGeorge syndrome) According to the statistics of Ashleigh et al., the rate of congenital heart defects for each common type of chromosomal abnormality is 80% in Trisomy 13, up to 100% in Trisomy 18, 40 - 50% in Trisomy 21, 25 - 35% in Monosomy X, 50% in Klinefelter's syndrome, 75% in DiGeorge's syndrome Common malformations are atrial septal defect, ventricular septal defect, hypoplasia of the left heart, tetralogy of Fallot Ultrasound combined with screening tests, prenatal diagnosis is very necessary to help detect early chromosomal abnormalities related to congenital heart defects Tests for chromosomal diagnosis by cell-molecular genetic methods from amniotic fluid samples, placental spines These methods can detect chromosomal structural and numerical abnormalities, but have not detected a number of minor chromosomal microsegment abnormalities that are associated with congenital heart defects The BoBs (BACs-on-Beads) technique was used to detect additions or deletions of DNA fragments (Deoxyribonucleic acid), in chromosomal regions associated with nine microdeletion syndromes in addition to abnormalities associated with common chromosomes According to author Choy (2014), BoBs technique has a sensitivity of 96.7%, a specificity of 100% Using a combination of multiple diagnostic tests will correctly detect fetal chromosomal abnormalities that may be missed when only chromosomal diagnostic test is performed With the aim of understanding chromosomal abnormalities in fetuses with congenital heart defects, there will be more clinical evidence for obstetricians in the counseling and management of pregnant women Therefore, we carry out the project "Research on prenatal diagnosis in common congenital heart defects", Objectives: Evaluation of diagnostic results of common congenital heart defects by ultrasound at the National Hospital of Obstetrics and Gynecology Evaluation of the relationship between congenital heart defects and chromosomal abnormalities NEW CONTRIBUTIONS OF THE THESIS The results of the thesis evaluate the rate of common congenital heart defects in the fetus Identify groups of congenital heart defects according to the classification of single heart defects subtypes, combining many types; simple and complex heart malformation subtypes; combining– no combining of abnormal extracardiac organs subtypes Applying two chromosomal diagnostic techniques, Karyotyping and BOBs, the results determined the high rate of chromosomal abnormalities in fetuses with congenital heart defects Research results have evaluated the relationship between the rate of chromosomal abnormalities according to groups of congenital heart defects Structure of thesis Thesis includes 135 trang, with main parts: - Introduction pages - Chapter I: Literature review 43 pages - Chapter II: Methodology 23 pages - Chapter II: Results 28 pages - Chapter IV: Discussion 36 pages - Conclusion pages - Recommendation page The thesis includes 35 tables, 18 pictures, 14 figure and 143 references (in which, 23 Vietnamese references, 120 English references), journal articles related to the thesis CHAPTER LITERATURE REVIEW 1.1 Fetal heart anatomy and formation 1.1.1 Anatomy of fetal heart The fetal heart consists of two parts, the chambers of the heart and the great blood vessels The pulmonary artery and the right ventricle are located anteriorly, and the right side, the aorta, and the left ventricle are posteriorly and to the left The aorta and pulmonary arteries are communicated by an arterial catheter The two right and left atria are the posteriormost part of the base of the heart, approximately equal in size, and communicate through the foramen ovale The left atrium receives blood from the pulmonary vein and the right atrium receives blood from the superior and inferior vena cava The right and left ventricles are approximately equal in size and are separated by the interventricular septum 1.1.2 Embryology of the fetal heart The heart is formed from the primordial heart duct starting on the 18th day of the embryo and completed by the end of the 6th week of pregnancy At the end of the fourth week of embryonic development, five segments are distinguished in the primitive heart tube in the head-tail direction (1) truncus arteriosus is the source of great blood vessels; (2) bulbus cordis: is the connection of the artery to the ventricle and also a part of the right ventricle; (3) primitive ventricle: is the source of the later left ventricle and right ventricle; (4) primitive atrium: is the source of the later left atrium and right atrium The primitive atrium is separated from the primitive ventricle by the atrioventricular duct; (5) Venous sinuses: contribute to the creation of the permanent atrium and are the site of the fusion of the veins into the atrium In the process of subsequent development, the primitive heart tube becomes a permanent heart, three main phenomena occur simultaneously: elongation and folding of the primitive heart duct; Irregular enlargement of the primitive heart tube; The creation of the septum of the heart The main septum of the heart is formed between day 27 and day 37 of development when the embryo reaches a length of 5mm to 16-17mm 1.2 Classification of congenital heart defects Congenital heart defects (CHD) are defects of the heart or large blood vessels caused by the cessation or underdevelopment of components of the embryonic heart during fetal life 1.2.1 Clinical classification of congenital heart defects General congenital defect of the heart Non-cyanotic CHD, there is no flow Non-cyanotic CHD with left-right shunt CHD with cyanosis, right-left shunt 1.2.2 Classification according to the complexity of congenital heart defect Table 1.1 Classification according to the complexity of congenital heart defect Level Congenital heart defect Atrial communication Simple Ventricle septal defect Pulmonary arteries stenosis Ductus arteriosus Moderate Complex Ebstein’s disease Aortic stenosis Tetralogy of Fallot moderate All malformations causing cyanosis Ventricular abnormalities Dual-outlet ventricles Tricuspid valve atrophy Atrioventricular canal defect Transposition of the great artery Tetralogy of Fallot complex 1.3 Ultrasound diagnosis of congenital heart defect of the fetus 1.3.1 Ultrasound diagnostic methods 1.3.2 Value of ultrasound in the diagnosis of congenital heart defect 1.3.3 Fetal echocardiography basic sections • Cross-section of a four-chambered heart The 4-chamber view is considered a screening technique for CHD and does not require special ultrasound skills because imaging is easy to perform in the chest cross-section Some heart diseases have a normal 4-chamber view, which is also the biggest limitation of the routine use of the 4-chamber view of screening for CHD malformations The 4-chamber view of the heart is considered normal with the following conditions: - The size of heart occupies about 1/3 of the rib cage and 2/3 of the heart is located in the left chest - The axis of the heart make an angle of about 45° with the midline - Two ventricles: have the same size in terms of ventricular chambers and muscle thickness The right ventricle is usually located anteriorly, just behind the anterior chest wall The left ventricle is located between the right ventricle and the left lung - Two atria: Similar size Both atria are connected to the respective ventricles through the atrioventricular valve, with the foramen oval located in the middle third - Atrioventricular valves: regular opening and closing, tricuspid valve attached and lower than the mitral valve - Interventricular septum: uninterrupted, continuous from the apex to the base of the atrioventricular valve - The left atrium is located behind and close to the fetal spine, van Vieussen is always located in the left atrium The right atrium is located anterior to and far from the fetal spine - The left ventricle is located slightly posteriorly, and the wall is smooth The right ventricle is located anteriorly, near the chest wall, with thick walls Heart defects have a normal 4-chamber view - Tetralogy of Fallot - Transposition of the artery - Right ventricle with two outflow tracts with a small ventricular septal defect - Arterial trunk - Mild stenosis of the tricuspid valve - Aortic arch abnormality Heart defect with an abnormal 4-chamber view - No aortic/mitral valve hole - No orifice of pulmonary valve/tricuspid valve - Ebstein's disease/ Tricuspid valve prolapse - Atrioventricular canal defect - Large hole ventricular septal defect - Single ventricle defect - Severe stenosis of the aortic/pulmonary valve - Severe narrowing of the aortic waist - Abnormal static connection vein - Cardiomyopathy/cardiac tumor • Cross section of chambers From the 4-chamber view, which directs the ultrasound beam to the head, the left ventricular outflow tract is located between the two atrioventricular valves Tilt more cephalad to reveal the valve and root of the aorta In a normal heart, the aortic root points to the right along the longitudinal axis of the heart In the 5-chamber view, the angle between the ascending aorta and the interventricular septum is wide In aortic descent, there is no such course, the axis between the pulmonary artery and the left ventricle is approximately parallel to the longitudinal axis of the interventricular septum • Three-vessel view The 3-vessel view is a cross-section of the upper fetal thorax, performed by moving the transducer from the parallel 4-chamber view cephalad to the upper mediastinum of the fetus Because the majority of severe CHD involve the ventricular outflow tract, this view is considered an alternative view in ventricular outflow examination • Cross section of aortic arch and ductus arteriosus (section of vessels and trachea) From the 3-vessel view, tilting the probe slightly towards the right end, the aortic arch and the ductus arteriosus will be seen simultaneously In a normal fetus, this view is V-shaped, representing communication between the aortic arch and the ductus arteriosus, with the descending aorta on the left anterior side of the spine The left branch of the V-shape is formed by the pulmonary trunk and the ductus arteriosus, and the right branch is formed by the aortic arch In cross section, both arches are located to the left of the trachea (filled with amniotic fluid) In a normal fetus, there is no vascular structure behind the trachea, and any blood vessel located behind it is considered abnormal • Longitudinal view of superior and inferior vena cava (2 veins) This view is obtained by placing the transducer vertically along the fetal body, just to the right of the midline Alternatively, it is easy to perform by moving the transducer slightly to the right side of the thorax from the longitudinal section of the aortic arch Because this view shows the connection of the superior and inferior vena cava to the right atrium, it is also known as the bi-vein view • Longitudinal section of the aortic arch This view is performed by cutting along the fetal body with the transducer pointing from the right sternum to the left shoulder For the chambers of the heart, this view shows a cross section of the atria with a longitudinal view of the aortic arch • Cross section of aortic valve (right ventricular outflow tract) Because the fetal heart has a horizontal position, the cross-sectional area of the fetal heart is roughly equivalent to the longitudinal section of the fetus From the longitudinal axial view parallel to the fetal spine, this view is made by gently rotating the transducer to the left side of the fetus, so that the examination view is from the right hypochondrium to the left shoulder By maintaining this orientation and gradually moving toward the left thorax of the fetus, a series of views from the base to the apex of the heart are recorded The shortaxis view of the heart was performed by scanning the ultrasound beam to the left from the longitudinal view of the aortic arch Since the origin of the aorta is nearly parallel to the longitudinal axis of the heart, the short axial view shows that the origin of the aorta is transversed Furthermore, since the right ventricular outflow tract is roughly perpendicular to the left ventricular outflow tract, the right ventricular outflow tract is found in the longitudinal axis This is because in a normal heart, the great arteries wrap around each other 25 Table 3.14 he relationship between characteristics of congenital heart defects single/combined and chromosomal abnormalities CHD Single CHD Combined p Chromosomes CHD 0,002 Chromosomal 127 (39,81%) (17,65%) abnormalities Normal 192 (60,19%) 42 (82,35%) chromosomes 319 51 Total Comment: The rate of chromosomal abnormalities in the group of fetuses with single CHD was 39.81% higher than that in the group with combined CHD (17.65%), the difference was statistically significant with p = 0.002 Table 3.21 Relationship between congenital heart defects with other organs and chromosomal abnormalities Abnormal organs With Without p Chromosomes abnormal abnormal organ organ Chromosomal abnormalities 80 (59,26%) 56 (23,83%) < 0,001 Chromosomal normalities 55 (40,74%) 179 (76,17%) 135 235 Total Comment: The rate of chromosomal abnormalities in the group with other organ abnormalities was 59.26% higher than in the group without combination (23.83%), the difference was statistically significant with p < 0.001 26 Table 3.22 Đặc điểm loại bất thường NST nhóm dị tật tim bẩm sinh Đặc điểm Abnormal Abnormal bất thường number of chromosomal Tổng NST chromosomes structure Nhóm dị tật Quantity Ratio Quantity Ratio TBS 60 72,29% 23 27,71% 83 Simple CHD 31 58,49% 22 41,51% 53 Complex CHD 86 67,72% 41 32,28% 127 Signgle CHD 55,56% 44,44% Combined CHD With abnormal 63 78,75% 17 21,25% 80 organ Without 28 50,0% 28 50,0% 56 abnormal organ Comment: Abnormal numbers of chromosomes are common in cases with simple CHD malformation (72.29%), and in cases with organ coordination (78.75%) Structural abnormalities of the chromosomes are encountered in many cases of complex CHD and combined CHD malformations 3.2.4 Value of Karyotyping and BOBS techniques in diagnosing chromosomal abnormalities in fetuses with congenital heart defects Table 3.30 Evaluation of the homogeneity of Karyotyping and BOBS techniques Karyotyping Total Chromosomal Chromosomal abnormalities normalities Chromosomal 67 26 93 abnormalities BOBS Chromosomal 12 188 200 normalities 79 214 293 Total 0,69 Kappa 87,0% Similarity ratio Comment: There were 293 pregnant women performing techniques at the same time Karyotyping and BOBS techniques have a similar diagnosis rate of 87.0%, with Kappa value = 0.69 27 CHAPTER DISCUSSION The research results collected 370 cases with full selection criteria to be included in the study 4.1 Diagnostic results of common congenital heart defects by ultrasound at the National Hospital of Obstetrics and Gynecology 4.1.1 General characteristics of pregnant women The results of our study showed that the fetus was diagnosed with CHD at the gestational age of 21.3± 3.6 (16 weeks - 33 weeks) Similar to Mademont Soler's study (2013) on the study CHD disease and chromosomal abnormalities, the average gestational age of amniocentesis are 23 weeks days (15-38 weeks), author Lou (2018), also recorded the gestational age for CHD diagnosis as 24.4 ± 3.8 weeks Some cases of late arrival at the Center for Prenatal Diagnosis, Central Obstetrics and Gynecology Hospital are sent up from the lower level, in cases of late detection of CHD anomalies accompanied by chromosomal abnormalities, the counseling for termination of pregnancy is very hard 4.1.2 Character of congenital heart defects 4.1.2.1 Rate of congenital heart defects In this study, we recorded the occurrence rate of common congenital heart defects, in which ventricular septal defect alone accounted for a large proportion with 51,20%, the ventricular septal defect may be encountered alone or in a combined group of malformations Other malformations accounted for a decreasing rate, respectively, tetralogy of Fallot ((18,03%) atrioventricular septal defect ((7,93%), and ventricular hypoplasia (4.81%)… The remaining malformations were found in less than 10 cases The study results recorded 86.22% single CHD and 13.78% of combined heart defects The group of simple CHD in cases with only one type of CHD defect, without accompanying other heart defects However, in our results, we classified tetralogy of Fallot in the group of cardiac malformations alone because this type of abnormality includes characteristic anomalies in combination Some studies on CHD in Vietnam show that some common malformations are ventricular septal defect, ventricular hypoplasia, 28 tetralogy of Fallot, and atrioventricular septal defect However, the rate of occurrence in the studies is different: the results of author Phan Quang Anh on CHD in a study 10 years ago at the National Hospital of Obstetrics and Gynecology, were recorded out of 276 fetuses with CHD, and ventricular septal defect had the highest rate (32.2%), and other malformations had a lower number respectively: ventricular hypoplasia (21.4%), tetralogy of Fallot (11.9%) ), atrioventricular septal defect (9.4%) In the results of author Le Kim Tuyen (2014), in a group of 553 fetuses with CHD anomalies, atrioventricular septal defect accounted for the highest rate (21.9%), followed by the ventricular septal defect , ventricular hypoplasia, tetralogy of Fallot 4.1.2.2 Classification of simple heart defects and complex heart defects Our results recorded that the simple CHD group was 53.24% and the complex CHD group accounted for 46.76% Thus, simple malformations account for more numbers than complex malformations, this result is similar to some other studies such as in the study of author Wu et al (2017), chromosomal analysis in In children with CHD malformation, the results recorded that the rate of children with simple and complex CHD was 58.7% and 41.3%, respectively The study by Qiu et al (2020) recorded a lower rate of simple CHD compared with the complex group, the results were: 681/1492 (45.64%) and 811/1492 (54.36%), respectively 4.1.2.3 Features of congenital heart defects in combination with other organ abnormalities In our results, 135 cases of fetal malformation with CHD were combined with abnormalities other than the heart In which, divided into groups/organ systems, abnormality of face - neck accounts for the highest rate: 37.23%, followed by systems/groups of organs with less frequency: nervous system, respectively 23.94%), musculoskeletal system (18.62%), digestive system (8.51%), urinarygenitourinary system (7.98%), and respiratory system (3.72%) Besides, we further analyzed the characteristics of organ coordination according to the group of TBS malformations, in which the rate of pregnancy with other organ abnormalities in the CHD group alone accounted for 40.1% higher than that of the CHD with combined TBS malformation group (13.73%), p < 0.0001; and the rate of other 29 organ abnormalities in the simple TBS group accounted for 49.24% higher than the complex TBS malformation group (21.97%) the difference was statistically significant with p < 0.0001 Thus, with simple and simple cases of TBS pregnancy, other organ abnormalities may be encountered 4.1.2.4 Some common congenital heart defects Ventricular septal defect The study results noted that ventricular septal defect was 37.56% in the group with only defect, besides, this defect also appeared in the group with other heart defects at 17.37%, other organ combinations were 42.25% and other cardiac and extracardiac abnormalities were 2.82% In the study on comparing the results of prenatal and postnatal diagnosis of CHD malformation by author Le Minh Trac, the highest rate of the ventricular septal defect was also recorded (before birth was 40.6%, after birth was 40.6% after birth, after birth) the birth rate is 39.1%) However, in the study of author Le Kim Tuyen, ventricular septal defect accounted for 14.8%, taking third place, after the syndrome of left heart hypoplasia and atrioventricular septal defect The sensitivity of fetal echocardiography in the diagnosis of ventricular septal defect is 60.6% and the specificity is 99.3% Our study shows that ventricular septal defect accounts for a large number and have a high rate that is superior to other heart defects, as well as in other studies The ventricular septal defect has the most occurrence rate, both in the group of malformations alone and in combination malformations A ventricular septal defect is a simple malformation that can be treated early and gives good results after birth Our study subjects were all pregnant women who agreed to have an amniocentesis to determine chromosomes after having fetal echocardiography results There are many pregnant women who agree to terminate the pregnancy, not to chromosomes when knowing that the fetus has a CHD malformation, especially in severe cases of CHD Therefore, the rate of a ventricular septal defect in our study is very high Tetralogy of Fallot Recently reported prenatal diagnosis rates for tetralogy of Fallot range from 30% to 60% Author Le Kim Tuyen reported that tetralogy of Fallot accounted for 7.2%, taking the 4th after the 30 syndrome of left heart hypoplasia and atrioventricular and ventricular septal defect The sensitivity of fetal echocardiography in the diagnosis of tetralogy of Fallot is 85.7% and the specificity is 100% Among the common antenatal CHD malformations, tetralogy of Fallot has good sensitivity and very high specificity In our study, there were 75 cases of tetralogy of Fallot fetuses, 77.33% of cases were not associated with organs other than the heart and 226.7% were associated What is special in our study is that the majority of cases of tetralogy of Fallot are not associated with other heart defects, and the number of organ abnormalities is small Atrioventricular canal defect Our study obtained 33 fetuses with atrioventricular septal defect, accounting for 8.9% of all types of CHD malformations in which there were 66.7% cases of ventricular septal defect alone, case with other heart defects and 30.3% cases of abnormal combination in other organs Research Le Van Tuyen (2014) reported that atrioventricular septal defect accounted for 21.9%, in second place after hypoplastic left heart syndrome The sensitivity of fetal echocardiography in the diagnosis of this malformation is 91.7% and the specificity is 99.9%, finding that in the common antenatal CHD malformations, diagnostic ultrasound has a high sensitivity to this anomaly Transposition of the great arteries In the results of our study, we recorded the rate of fetuses with Transposition of the great arteries was 21/370, 5.05% (table 3.4) There were only cases of Transposition of the great arteries single and 16 cases of pregnancy combined with other heart defects, cases with a combination of other heart defects and noncardiac organ defects, and case of mixed malformations noncardiac organ defects (Chart 3.6) Thus, the transposition of the great arteries is often combined with other heart malformations, in which we recorded 17/21 cases associated with ventricular septal defect and case combined with left ventricular hypoplasia, right ventricular bidirectional pathology go out A study by the author Gurleen recorded 155 cases of transposition of the arteries, of which 84 cases (54.2%) were simple and 71 cases (45.8%) were combined ventricular septal defect Hypoplastic heart syndrome 31 Our results recorded 4.81% of fetuses with ventricular hypoplasia (right or left) Of these, 50.0% were isolated ventricular hypoplasia, 6/20 fetuses were associated with ventricular hypoplasia with other heart defects, and 4/20 cases were associated with other organ abnormalities Research results by Le Kim Tuyen (2014), hypoplastic left heart syndrome accounted for 8.5% The sensitivity of fetal echocardiography in the diagnosis of hypoplastic left heart syndrome is 85.7% and the specificity is 100% 4.1.3 Value of echocardiography in the diagnosis of congenital heart defects During the follow-up of nursing schools and have given birth, we collected postnatal ultrasound results of 105 babies 4.1.3.1 Correct diagnosis rate The rate of correct diagnosis according to prenatal diagnosis was 87/105 (82.86%) The correct diagnosis rate in the simple CHD malformation group was 83.33%, and in the complex group was 80.92% Among the common CHD anomalies, the ventricular septal defect has a correct diagnosis rate of 47/56 (82.93%), and the tetralogy of Fallot is 25/29 (86.21%) Our results are not significantly lower than some other studies such as that of author Huang Q (2009), which is 87.89%; author Cui D (2015) is 92.9%; author Qiu X (2020) the accuracy of prenatal ultrasound in diagnosing complex and simple (90.5–91.66%) CHD (98.6%) Le Minh Trac (2018), a study on the initial assessment of prenatal and postnatal diagnosis of CHD in newborns at the National Hospital of Obstetrics and Gynecology, recorded the following results: the rate of prenatal CHD detection was consistent with the diagnosis in the neonatal period was 93.6% 4.1.3.2 Analysis of misdiagnosis of congenital heart defects We have 18 cases with misdiagnosis after birth, including cases with normal heart without malformation and 10 cases with other type of malformation The rate of misdiagnosis was recorded in many studies, in the study of Trivedi et al Reported the correct diagnosis rate of antenatal doctors was 77.9%, that of paediatricians was 85 %, the combined diagnosis of groups of doctors is 81.7%, and the rate of misdiagnosis is 18.3% Some reasons lead to misdiagnosis or difficulty to diagnosis such as: polyhydramnios or oligohydramnios, congenital malformations, fetal hygroma, fetal edema, maternal characteristics The most common misdiagnosis 32 include ventricular septal defect, pulmonary stenosis, common artery, and coarctation of the aorta We recorded cases with the same complex malformation group, although there were errors in the diagnosis of the type of malformation, but had the same group of disease prognosis, level of treatment, and care at specialized levels However, there are cases of postnatal diagnosis in complex CHD but prenatal diagnosis in the simple CHD group; cases of postpartum diagnosis in the group of simple CHD but prenatal diagnosis in the complex CHD group Cases of misdiagnosis between groups of simple-complex CHD, related to the problem of prognosis and treatment of pediatric patients after birth Therefore, it is necessary to recommend doctors for prenatal diagnosis, to further improve ultrasound capacity to limit diagnostic errors 4.2 Association between congenital heart defects and chromosomal abnormalities 4.2.1 Chromosome results in fetus with congenital heart defects 4.2.1.3 Chromosome results Evaluation of fetal chromosomes, we recorded the following results: 364 pregnant women agreed to perform Karyotyping technique, in which the detection rate of chromosomal abnormalities was 29.67% 299 pregnant women agreed to perform BOBS technique, in which the detection rate of chromosomal abnormalities was 31.1% The rate of chromosomal abnormalities in fetuses with CHD was 136/370 (36.76%) Features of chromosomal abnormalities of CHD include: Abnormal number of chromosomes is 91/136 (66.91%), in which trisomy 18 accounts for the highest rate with 62.6%; Abnormalities in chromosome structure are 45/136 (33.1%), in which chromosome deletion accounts for a high rate with 48.9% Research results of Do Quang Anh (2010), the rate of fetus with chromosomal abnormalities is 48%, trisomy 18 accounts for the highest rate of 58.3% In the study of Le Van Tuyen (2014), only 57 (36%) pregnant women with CHD agreed to amniocentesis with an abnormal rate of 12.3% In the study of Luo et al (2018), the rate of chromosomal abnormalities in fetuses with CHD was 140/362 (38.7%) The report of author Cai et al (2018) analyzed Karyotyping, the rate of fetus with CHD with chromosomal abnormalities was 19/146 - 13.01% When applying CNV, 22 more abnormal cases 33 (15.2%) were detected, of which 15 were pathogenic, were clinically significant variants and were clinically significant In our study, when applying two techniques Karryotyping and BOBS, a high rate of chromosomal abnormalities was identified in fetuses with congenital heart defects 4.2.2 The relationship between chromosomal abnormalities and groups of congenital heart defects Evaluation of the relationship between chromosomal abnormalities and simple/complex CHD group has a higher rate of chromosomal abnormalities in the group of fetuses with simple CHD, 42.13% higher than in the complex CHD group mixed (30.64%), the difference was not statistically significant with p = 0.022 Some other studies also did not record an association between chromosomal abnormalities and type of CHD In the study of author Wu et al (2017), analyzing chromosomes in children with CHD, the results recorded that the rate of children with simple and complex CHD was 58.7% (61/ 104) and 41.3% (43/104) Chromosomal abnormalities in 31.1% of children with simple malformations and 23.2% with complex malformations (p>0.05); The detection rate of chromosomal abnormalities in simple CHD and syndromic CHD was 17.9% and 33.8%, respectively (p > 0.05) Our results when analyzing the rate of chromosomal abnormalities in the group of fetuses with a combination of other organ abnormalities is 59.26%, which is statistically significantly higher than in the group without the combination (23.38%) The rate of chromosomal abnormalities in the group of fetuses with simple CHD with other organs was higher than the rate in the group of simple CHD without other organs (60.8% vs 24.0%, p < 0.001) Thus, cases with anomalies in coordination of organs are likely to experience chromosomal abnormalities Author Qui et al (2020) also noted a statistically significant difference: the rate of chromosomal abnormality 41/103 (39.8%) in the group with organ coordination compared with 7/132 (5, 5) 3%), (p