Prevalence of congenital heart defects in monochorionic/diamniotic twin gestations: a systematic literature review

Indications for fetal echocardiography: consensus and controversies among evidence-based national and international guidelines

OBJECTIVE

Fetal echocardiography (FE) is an indication-driven examination for pregnant women with a fetus at high risk for congenital heart disease (CHD). Several familial, maternal and fetal factors are reported to increase the risk of CHD. The aim of this study was to highlight the existing differences in recommended indications for FE among recently published guidelines and consensuses of experts.

METHODS

Guidelines and expert consensuses published from January 2008 to October 2023 were identified through a systematic literature search. FE guidelines and consensus statements were excluded if not written in the English language and if indications for FE were not reported. All familial, maternal and fetal risk factors for CHD reported in the consensuses and guidelines were listed and comparisons were made between documents. The agreement or disagreement for each risk factor between guidelines and consensuses was classified as: complete agreement (all analyzed documents reported the same indication); partial agreement (all documents considered a risk factor as an indication, but with inconsistency in its definition); or complete disagreement (inconsistency between documents for the considered risk factor as an indication).

RESULTS

Six guidelines and expert consensuses that met the inclusion criteria were identified. Overall, a total of 17 risk factors were identified as an indication for FE. Complete agreement was reached for 3/17 (17.6%) risk factors, all of which are fetal risk factors (suspected CHD at the anomaly scan, presence of major fetal extracardiac abnormality and non-immune hydrops fetalis). Partial agreement was recorded for 8/17 (47.1%) risk factors (family history of CHD, increased nuchal translucency, multiple gestation, maternal diabetes mellitus, maternal phenylketonuria, maternal infection, maternal autoimmune disease and autoantibody positivity, and teratogen exposure). Complete disagreement was recorded for 6/17 (35.3%) risk factors (inherited genetic disease associated with CHD, fetal genetic anomaly, suspected abnormality of heart rate or rhythm, first-trimester sonographic markers of CHD, abnormality of umbilical cord and venous system, and use of assisted reproductive technology).

CONCLUSIONS

Areas of controversy regarding which CHD risk factors warrant FE were greater in quantity than were the areas of consensus. An internationally standardized agreement would be valuable for physicians and guideline developers. For many risk factors, further evidence is needed to justify their use as an indication for FE. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.

Cardiac function and neurological development in complicated monochorionic pregnancies: Current evidence and clinical implications

Monochorionic twin pregnancies, characterized by a shared placenta and unique vascular architecture, face significantly elevated risks of perinatal complications compared to dichorionic and singleton pregnancies. This review examines the pathophysiology, cardiovascular, and neurological adaptations in three primary complications of monochorionic pregnancies: Twin-to-Twin Transfusion Syndrome (TTTS), Selective Fetal Growth Restriction (sFGR), and Twin Anemia Polycythemia Sequence (TAPS). TTTS disrupts hemodynamic balance, leading to distinct cardiac dysfunctions and increased neurodevelopmental injury (NDI). In sFGR, unequal placental sharing induces cardiovascular and neurological disparities between twins, while TAPS causes chronic anaemia and polycythemia with associated risks of brain injury. Advances in fetal therapy, such as fetoscopic laser surgery, have significantly improved survival, yet long-term sequelae remain concerning. This review emphasizes the importance of specialised prenatal care, multidisciplinary management, and comprehensive postnatal follow-up to mitigate adverse outcomes. The findings call for further research into the mechanisms of fetal adaptation and injury, aiming to refine diagnostic tools and therapeutic strategies.

Chromosomal analysis and short-term outcome of prenatally diagnosed congenital heart disease

Congenital structural heart disease (CHD) is the leading cause of infant death from birth defects. Postnatal survival primarily depends on the type and severity of the defect. In addition, worse cardiac prognosis is observed when extra-cardiac anomalies (ECA) are associated. This retrospective chart review was aimed at finding markers for short-term outcome prediction of prenatally-diagnosed complex CHD, focusing in particular on the impact of CHD category, of CHD severity score and of prenatal or postnatal diagnosis of ECA or chromosomal anomalies on 4 primary outcomes: termination of pregnancy (TOP), intrauterine fetal demise, neonatal mortality and 1-year-survival rate. We reviewed medical files from 381 fetuses, presenting at our center between 2018 and 2021 with CHD for which prenatal advice by a pediatric cardiologist was sought. 341 fetuses met the inclusion criteria for the study. Twin pregnancies (7.62%; OR 4.76 (p < 0.001)) and pregnancies resulting from assisted reproductive technology (7.33%; OR 2.44 (p < 0.001)) were more prevalent compared to the general population. CHD categories and CHD severity scores, ranging from A (extremely high risk based on CHD or ECA type) to D (low risk), were assigned to each fetus. Prenatal or postnatal chromosomal microarray results were available for 232 fetuses (68%) and were abnormal in 30 (12.9%). Logistic regression analysis was used to determine significant predictors for the primary outcomes 'TOP', 'postnatal demise before the age of 1 month' and 'survival at the age of 1 year'. TOP was carried out significantly more with: prenatal genetic diagnosis, severity score A and severity score B. Interestingly, a prenatal genetic diagnosis was negatively correlated with pregnancy continuation, but it was not a significant predictor for postnatal mortality, while a postnatal diagnosis of a genetic disorder impacted early but not late postnatal mortality. In addition, postnatal mortality both before the age of 1 month or before the age of 1 year was significantly associated with lower postmenstrual age at birth, CHD severity score B and major ECA at birth. These results underscore the importance of genotyping and of accurate cardiac and extracardiac phenotyping for prognostication in fetuses with CHD.

Dichorionic Diamniotic Twin Pairs with Complex Congenital Heart Disease

Complex congenital heart disease (CHD) in each of dichorionic diamniotic (DiDi) twin pairs is extremely rare and has not been well characterized. Four DiDi twin pairs were included in this multi-institutional case series. The congenital cardiac abnormalities noted included tetralogy of Fallot (ToF) with pulmonary atresia and collaterals (n = 1), ToF with absent pulmonary valve (n = 1), ToF (n = 2), discontinuous right pulmonary artery (RPA) (n = 1), tricuspid atresia (TA) with normally related great arteries and pulmonary valve stenosis or atresia (n = 2) and coarctation of aorta (CoA) with bicuspid aortic valve (BAV) and borderline left-sided structures (n = 1). Genetic testing was obtained on seven of the eight twins but did not reveal any causal abnormality. A comprehensive review of literature yielded another 8 DiDi twin pairs with complex CHD. The CHD noted in these twin pairs included ToF (n = 2), CoA (n = 4), corrected transposition of great arteries (ccTGA) (n = 2), truncus arteriosus (n = 2), complete common atrioventricular canal (CCAVC) (n = 2), hypoplastic left heart syndrome (HLHS) (n = 2), Shone's complex (n = 1), and hypoplastic right heart syndrome (HRHS) (n = 1). Limited genetic testing was obtained on 4 of these twins and revealed trisomy 21 in a twin pair. Conotruncal abnormalities (42%), CoA (21%), and abnormalities of the right ventricle, the right ventricular outflow tract and pulmonary arteries (17%) are more prevalent in DiDi twins with complex CHD. Clustering of these abnormalities suggests a possible genetic basis; however, genetic testing was obtained on eleven of the twins, and except for trisomy 21 in a twin pair both of whom had CCAVC, did not reveal any causal abnormality. A major direct genetic contribution is therefore unlikely and like other CHD, the underlying etiopathological basis is likely multifactorial.

Society for Maternal-Fetal Medicine Consult Series #72: Twin-twin transfusion syndrome and twin anemia-polycythemia sequence

Thirty percent of spontaneously occurring twins are monozygotic, of which two-thirds are monochorionic, possessing a single placenta. A common placental mass with shared intertwin placental circulation is key to the development and management of complications unique to monochorionic gestations. In this Consult, we review general considerations and a contemporary approach to twin-twin transfusion syndrome and twin anemia-polycythemia sequence, providing management recommendations based on the available evidence. The following are the Society for Maternal-Fetal Medicine recommendations: (1) we recommend routine first-trimester sonographic determination of chorionicity and amnionicity (GRADE 1B); (2) we recommend that ultrasound surveillance for twin-twin transfusion syndrome begin at 16 weeks of gestation for all monochorionic-diamniotic twin pregnancies and continue at least every 2 weeks until delivery, with more frequent monitoring indicated with clinical concern (GRADE 1C); (3) we recommend that routine sonographic surveillance for twin-twin transfusion syndrome minimally include assessment of amniotic fluid volumes on both sides of the intertwin membrane and evaluation for the presence or absence of urine-filled fetal bladders, and ideally incorporate Doppler study of the umbilical arteries (GRADE 1C); (4) we recommend fetoscopic laser surgery as the standard treatment for stage II through stage IV twin-twin transfusion syndrome presenting between 16 and 26 weeks of gestation (GRADE 1A); (5) we recommend expectant management with at least weekly fetal surveillance for asymptomatic patients continuing pregnancies complicated by stage I twin-twin transfusion syndrome, and consideration for fetoscopic laser surgery for stage I twin-twin transfusion syndrome presentations between 16 and 26 weeks of gestation complicated by additional factors such as maternal polyhydramnios-associated symptomatology (GRADE 1B); (6) we recommend an individualized approach to laser surgery for early- and late-presenting twin-twin transfusion syndrome (GRADE 1C); (7) we recommend that all patients with twin-twin transfusion syndrome qualifying for laser therapy be referred to a fetal intervention center for further evaluation, consultation, and care (Best Practice); (8) after laser therapy, we suggest weekly surveillance for 6 weeks followed by resumption of every-other-week surveillance thereafter, unless concern exists for post-laser twin-twin transfusion syndrome, post-laser twin anemia-polycythemia sequence, or fetal growth restriction (GRADE 2C); (9) following the resolution of twin-twin transfusion syndrome after fetoscopic laser surgery, and without other indications for earlier delivery, we recommend delivery of dual-surviving monochorionic-diamniotic twins at 34 to 36 weeks of gestation (GRADE 1C); (10) in twin-twin transfusion syndrome pregnancies complicated by posttreatment single fetal demise, we recommend full-term delivery (39 weeks) of the surviving co-twin to avoid complications of prematurity unless indications for earlier delivery exist (GRADE 1C); (11) we recommend that fetoscopic laser surgery not influence the mode of delivery (Best Practice); (12) we recommend that prenatal diagnosis of twin anemia-polycythemia sequence minimally require either middle cerebral artery Doppler peak systolic velocity values >1.5 and <1.0 multiples of the median in donor and recipient twins, respectively, or an intertwin Δ middle cerebral artery peak systolic velocity >0.5 multiples of the median (GRADE 1C); (13) we recommend that providers consider incorporating middle cerebral artery Doppler peak systolic velocity determinations into all monochorionic twin ultrasound surveillance beginning at 16 weeks of gestation (GRADE 1C); and (14) consultation with a specialized fetal care center is recommended when twin anemia-polycythemia sequence progresses to a more advanced disease stage (stage ≥II) before 32 weeks of gestation or when concern arises for coexisting complications such as twin-twin transfusion syndrome (Best Practice).

Rare Earth Element Content in Hair Samples of Children Living in the Vicinity of the Kola Peninsula Mining Site and Nervous System Diseases

The aim of this study is to assess the rare earth element (REE) content in hair samples of children living in Lovozero village, near an REE mining site, and the possible effects of REEs on the prevalence of nervous system diseases in Lovozersky District (Murmansk region, Kola Peninsula). Fifty-three school-age children were recruited for the analysis of REE content in hair samples. REE (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) content was estimated by means of inductively coupled plasma mass spectrometry (ICP-MS). The analysis of REE content in the hair of children living in Russia, Kazakhstan, and China indicated REE intake from the environment. The possible contribution of REEs to nervous system disorders is supported by the link between the REE content in hair samples of children living near REE mining areas (China) and the manifestation of cognitive disorders in these children. It is also found that the prevalence of nervous system diseases in children aged 15-17 years is higher in Lovozersky District compared to the other districts of the Murmansk region. In this paper, the possible contribution of REEs to the prevalence of episodic paroxysmal disorders (G40-G47), cerebral palsy (G80-G83), and epilepsy and status epilepticus (G40-G41) is discussed.

Uncovering the Genetic Basis of Congenital Heart Disease: Recent Advancements and Implications for Clinical Management

Congenital heart disease (CHD) is the most prevalent hereditary disorder, affecting approximately 1% of all live births. A reduction in morbidity and mortality has been achieved with advancements in surgical intervention, yet challenges in managing complications, extracardiac abnormalities, and comorbidities still exist. To address these, a more comprehensive understanding of the genetic basis underlying CHD is required to establish how certain variants are associated with the clinical outcomes. This will enable clinicians to provide personalized treatments by predicting the risk and prognosis, which might improve the therapeutic results and the patient's quality of life. We review how advancements in genome sequencing are changing our understanding of the genetic basis of CHD, discuss experimental approaches to determine the significance of novel variants, and identify barriers to use this knowledge in the clinics. Next-generation sequencing technologies are unravelling the role of oligogenic inheritance, epigenetic modification, genetic mosaicism, and noncoding variants in controlling the expression of candidate CHD-associated genes. However, clinical risk prediction based on these factors remains challenging. Therefore, studies involving human-induced pluripotent stem cells and single-cell sequencing help create preclinical frameworks for determining the significance of novel genetic variants. Clinicians should be aware of the benefits and implications of the responsible use of genomics. To facilitate and accelerate the clinical integration of these novel technologies, clinicians should actively engage in the latest scientific and technical developments to provide better, more personalized management plans for patients.

Structural Anomalies in Multifetal Gestations

Multifetal gestations are at increased risk for structural anomalies relative to singletons. Determination of chorionicity is critical, as the risk is highest for monochorionic pregnancies. In a singleton gestation, counseling is structured around optimization of fetal outcomes and careful consideration of the patient's choices in management decisions. However, in multifetal gestations affected by a fetal anomaly, complex counseling with consideration for the pregnancy as a whole is necessary. We review the incidence of structural anomalies in twins and highlight unique considerations including selective termination for discordant anomalies. We emphasize the role of shared decision making between provider and patient.

Prevalence and detection rate of major congenital heart disease in twin pregnancies in Denmark

OBJECTIVE

To investigate the national prevalence and prenatal detection rate (DR) of major congenital heart disease (mCHD) in twin pregnancies without twin-to-twin transfusion syndrome (TTTS)-associated CHD in a Danish population following a standardized prenatal screening program.

METHODS

This was a national registry-based study of data collected prospectively over a 10-year period. In Denmark, all women with a twin pregnancy are offered standardized screening and surveillance programs in addition to first- and second-trimester screening for aneuploidies and malformation, respectively: monochorionic (MC) twins every 2 weeks from gestational week 15 and dichorionic (DC) twins every 4 weeks from week 18. The data were retrieved from the Danish Fetal Medicine Database and included all twin pregnancies from 2009-2018, in which at least one fetus had a pre- and/or postnatal mCHD diagnosis. mCHD was defined as CHD requiring surgery within the first year of life, excluding ventricular septal defects. All pregnancy data were pre- and postnatally validated in the local patient files at the four tertiary centers covering the entire country.

RESULTS

A total of 60 cases from 59 twin pregnancies were included. The prevalence of mCHD was 4.6 (95% CI, 3.5-6.0) per 1000 twin pregnancies (1.9 (95% CI, 1.3-2.5) per 1000 live births). The prevalences for DC and MC were 3.6 (95% CI, 2.6-5.0) and 9.2 (95% CI, 5.8-13.7) per 1000 twin pregnancies, respectively. The national prenatal DR of mCHD in twin pregnancies for the entire period was 68.3%. The highest DRs were in cases with univentricular hearts (100%) and the lowest with aortopulmonary window, total anomalous pulmonary venous return, Ebstein's anomaly, aortic valve stenosis and coarctation of the aorta (0-25%). Mothers of children with prenatally undetected mCHD had a significantly higher body mass index (BMI) compared to mothers of children with a prenatally detected mCHD (median, 27 kg/m2 and 23 kg/m2 , respectively; P = 0.02).

CONCLUSIONS

The prevalence of mCHD in twins was 4.6 per 1000 pregnancies and was higher in MC than DC pregnancies. The prenatal DR of mCHD in twin pregnancies was 68.3%. Maternal BMI was higher in cases of prenatally undetected mCHD. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Cardiac findings in newborn twins

AIMS

To evaluate cardiac findings in newborn twins from the general population and investigate if newborn twins may require systematic evaluation of cardiac parameters.

METHODS

Prospective cohort study of newborns with cardiac evaluation performed during the first month of life. Cardiac findings were compared 1:3 with matched singletons.

RESULTS

We included 412 newborn twins (16% monochorionic; 50% boys) and 1236 singletons. Comparing cardiac findings showed twins had an increased prevalence of non-severe structural heart disease (most common: ventricular septal defects in both groups), thinner left ventricular posterior wall in diastole (LVPWd; 1.82 vs. 1.87 mm, p = 0.02), smaller diameter of the left atrium (10.6 vs. 11.1 mm, p = 0.04), higher heart rate (148 vs. 144 bpm, p = 0.04), more left-shifted QRS axis (106 vs. 111°, p < 0.001), and lower maximum R-wave amplitude in V1 (927 vs. 1015 μV, p = 0.02) compared to singletons. After multifactorial adjustment for potential confounders, the effect of twinning on cardiac parameters persisted only for LVPWd (p < 0.05).

CONCLUSION

Despite contemporary surveillance, we found an increased prevalence of non-severe structural heart disease in a population-based cohort of newborn twins. However, the effect of twinning on cardiac parameters was modest and generally did not persist after correction for likely confounding factors.

Cardiac problems in the fetus: a review for pediatric providers

PURPOSE OF REVIEW

The aim of this study was to provide pediatric providers with a review of the diagnosis and management of fetal cardiac disease in the current era.

RECENT FINDINGS

Prenatal detection of congenital heart disease (CHD) has improved but is still imperfect. In experienced hands, fetal echocardiography can detect severe CHD as early as the first trimester and a majority of more subtle conditions in the second and third trimesters. Beyond detection, a prenatal diagnosis allows for lesion-specific counseling for families as well as for development of a multidisciplinary perinatal management plan, which may involve in-utero treatment. Given the diversity of cardiac diagnoses and the rarity of some, collaborative multicenter fetal cardiac research has gained momentum in recent years.

SUMMARY

Accurate diagnosis of fetal cardiac disease allows for appropriate counseling, pregnancy and delivery planning, and optimization of immediate neonatal care. There is potential for improving fetal CHD detection rates. Fetal interventions are available for certain conditions, and fetal and pediatric cardiac centers have developed management plans specific to the expected postnatal physiology.

Pulmonary valve stenosis in a recipient twin in twin-to-twin transfusion syndrome with successful balloon valvuloplasty after birth: a case report

BACKGROUND

Pulmonary stenosis (PS) is a congenital heart diseases (CHDs) with a spectrum of stenosis. Monochorionic (MC) twins are at increased risk of CHDs, especially acquired CHDs in twin-twin transfusion syndrome (TTTS). PS/Pulmonary atresia (PA) is a rare coincidence with TTTS. MC twin pregnancies have increased in last decades due to increasing in maternal age and extensive use of assisted reproductive technologies. Therefore, attention to this group is important for heart abnormalities, especially in twins with TTTS. Multiple cardiac abnormalities in MC twins with TTTS are to be expected due to cardiac hemodynamic changes and may be eliminated by Fetoscopic laser photocoagulation treatment. Prenatal diagnosis of PS is necessary given the importance of treatment after birth.

CASE PRESENTATION

We here present a case of coexistence of TTTS with PS in a growth restricted recipient twin who successfully treated with balloon pulmonary valvuloplasty in neonatal period. Also, we detected infundibular PS after valvuloplasty that treated with medical therapy (propranolol).

CONCLUSIONS

It is important to detect acquired cardiac abnormalities in MC twins with TTTS, and follow them up after birth to determine the need of intervention in neonatal period.

Prenatal detection of congenital heart disease at 12-13 gestational weeks: detailed analysis of false-negative cases

OBJECTIVES

To report on the early detection of congenital heart disease (CHD) in low- and high-risk populations managed at our hospital; and perform a detailed analysis of false-negative diagnoses, in order to derive possible recommendations on how to reduce their incidence.

METHODS

This was a retrospective observational study analyzing cases which underwent an ultrasound examination at the end of the first trimester at the Fetal Medicine and Surgery Unit of Gaslini Children's Hospital, Genoa, Italy, in the period January 2015 to December 2021. The study population included both low-risk pregnancies that underwent standard first-trimester combined screening and high-risk ones referred to our unit because of a positive combined test or suspicion of fetal anomalies raised in a regional community hospital. For each case, the following variables were retrieved and analyzed: number of fetuses, maternal body mass index, gestational age at first-trimester screening, whether the pregnancy was low or high risk, nuchal translucency thickness (normal or > 99th  centile), type of CHD, associated extracardiac anomalies, karyotype and pregnancy outcome. For low-risk pregnancies, suspicion of CHD was also recorded. In low-risk cases, sonographic cardiac screening comprised evaluation of the four-chamber view (grayscale and color/power Doppler) and three-vessel-and-trachea view (color/power Doppler). High-risk cases underwent early fetal echocardiography. False-negative cases were categorized according to likely cause of the missed diagnosis, as follows: human factor; technical factor; acoustic-window factor.

RESULTS

Gestational age at ultrasound ranged from 12 + 0 to 13 + 6 weeks (crown-rump length (CRL), 50.1-84.0 mm) in the low-risk group and from 11 + 5 to 13 + 6 weeks (CRL, 45.1-84.0 mm) in the high-risk group. Over the 7-year study period, 7080 pregnancies were evaluated in the first trimester. Of these, 6879 (7167 fetuses) were low-risk and 201 were high-risk cases. In the low-risk group, there were 30 fetuses with CHD (including 15 major and 15 minor CHD), yielding a prevalence of 4.2/1000 (2.1/1000 for major CHD). Nine of the 30 CHD cases were suspected at screening ultrasound (7/15 major CHD). Excluding cases in which the CHD would not be expected to be associated with a modification of the screening views and would therefore not be detectable on screening ultrasound, 7/12 cases of major CHD were detected, corresponding to a sensitivity of 58.3%. Among the 201 high-risk cases, there were 46 fetuses with CHD (including 44 major and two minor CHD), of which 43 were detected, corresponding to a sensitivity for early fetal echocardiography of 93.5%, or 97.7% if the two cases that were unlikely to be detectable on first-trimester screening were excluded. Analysis of the 11 (of 24) false-negative cases that would be expected to be picked up on screening views revealed that human error (image interpretation and/or scanning approach) was involved in all 11 cases and technical factors (excessive color priority (color-balance function) and/or incorrect plane alignment) were present in two. There was impairment of the acoustic window (associated with maternal obesity and/or twin gestation) as a cofactor in five of the 11 cases.

CONCLUSIONS

The sensitivity for detection of major CHD of early cardiac screening in low-risk pregnancy is under 60%, partly due to the natural history of CHD and, it seems, partly relating to human error and technical issues with image quality. Factors associated with false-negative diagnoses may be categorized into three types: human error, technical factors and acoustic-window impairment. We recommend: appropriate assessment with fetal posterior spine; that sufficient time is spent on assessment of the fetal situs; and that color/power Doppler settings are adapted to the individual case. A lower threshold for referring doubtful cases for early fetal echocardiography should be adopted in cases of maternal obesity and in twin gestation. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Predictors of dual demise within the first week after selective cord occlusion via radiofrequency ablation for complex monochorionic pregnancies

BACKGROUND

Selective cord occlusion is an option in complicated monochorionic multiple gestations with the goal of reducing the pregnancy by one fetus and to optimize the outcomes for the remaining fetus(es).

OBJECTIVE

This study aimed to determine the rate and associated risk factors of dual demise in complex monochorionic pregnancies after selective cord occlusion via radiofrequency ablation.

STUDY DESIGN

This was a single-center analysis of a prospective registry cohort of complex monochorionic pregnancies managed with selective cord occlusion via radiofrequency ablation between 2014 and 2021. A total of 167 pregnancies met the inclusion criteria and were evaluated on the basis of the intended outcome of dual demise vs singleton survival. Risk factors were compared between the 2 groups. The Mann-Whitney U test was used for continuous variables and the Fisher exact test was used for categorical variables.

RESULTS

The incidence of postprocedure dual demise within the first week after performing radiofrequency ablation was 10.8% (18/167). The risk was higher in pregnancies undergoing radiofrequency ablation for discordant anomaly, and this subcategory constituted 38.9% of pregnancies in the dual demise subgroup (P=.02). Lower intertwin estimated fetal weight discordance (P=.01) was associated with dual demise. Perioperative variables including gestational age at procedure, placental cord insertion distance, operative time, and radiofrequency ablation time were similar in those with and without dual demise.

CONCLUSION

Our results show that selective cord occlusion via radiofrequency ablation is a safe and reasonable option in complicated monochorionic pregnancies, with low rates of dual demise within the first week after the procedure.

Monochorionic twins with 15q26.3 duplication presenting with selective intrauterine growth restriction and discordant cardiac anomalies: A case report

BACKGROUND

Duplication of the distal end of chromosome 15q has been previously implicated in a characteristic overgrowth syndrome. Additionally, many patients have other congenital malformations, including cardiac, renal, genital, and musculoskeletal anomalies. However, some patients may present with intrauterine growth restriction and short stature. Different breakpoints within 15q, as well as different environmental factors, may underlie these varied presentations.

CASE PRESENTATION

We discuss monochorionic-diamniotic twins with a ~345 kb maternally inherited duplication in 15q26.3. The twins presented with discordant pathology-one twin with a single umbilical artery, selective intrauterine growth restriction, and multiple cardiac defects including aortic coarctation, aortic valve stenosis, and ventricular septal defect, whereas the other twin was unaffected. To our knowledge, this case represents the smallest reported duplication of distal 15q.

CONCLUSION

The discordant phenotype seen in the twins is likely due to a complex interplay between genetic and environmental causes. The affected infant presented prenatally with growth restriction and a single umbilical artery rather than overgrowth, potentially due to a unique breakpoint within 15q. This, in turn, may have produced hemodynamic perturbations between the twins, leading to discordant cardiac disease. Our report thus highlights the importance of genetic and nongenetic mechanisms underlying discordant anomalies in monochorionic twins.

Epigenetics and Congenital Heart Diseases

Congenital heart disease (CHD) is a frequent occurrence, with a prevalence rate of almost 1% in the general population. However, the pathophysiology of the anomalous heart development is still unclear in most patients screened. A definitive genetic origin, be it single-point mutation or larger chromosomal disruptions, only explains about 35% of identified cases. The precisely choreographed embryology of the heart relies on timed activation of developmental molecular cascades, spatially and temporally regulated through epigenetic regulation: chromatin conformation, DNA priming through methylation patterns, and spatial accessibility to transcription factors. This multi-level regulatory network is eminently susceptible to outside disruption, resulting in faulty cardiac development. Similarly, the heart is unique in its dynamic development: growth is intrinsically related to mechanical stimulation, and disruption of the intrauterine environment will have a direct impact on fetal embryology. These two converging axes offer new areas of research to characterize the cardiac epigenetic regulation and identify points of fragility in order to counteract its teratogenic consequences.

Crown-Rump Length Discordance, Increased Nuchal Translucency, and Detection of Fetal Structural Anomalies in Twin Pregnancies in the First Trimester: 5 Years of Experience in a Tertiary Hospital in China

OBJECTIVE

To evaluate the efficacy of the first-trimester ultrasound scan in the detection of fetal structural anomalies in twin pregnancies. To examine the association between increased nuchal translucency (NT) thickness, crown-rump length (CRL) or NT discordance, and detection of structural anomalies in a large twin series in China.

METHODS

We performed retrospective analysis of twin pregnancies who underwent 11-13⁺⁶ -week and second-trimester anomaly scan and booked at Beijing Obstetrics and Gynecology Hospital between January 2012 and December 2016. Measurement of fetal CRL/NT and assessment of fetal anatomic structures were based on standard (not detailed) protocols. Conjoined twins and twin-reversed arterial perfusion sequence (TRAPS) were excluded from structural anomalies. The diagnostic performance of first-trimester ultrasound in detection of fetal structural anomalies in twins was determined and compared with that of second trimester. The accuracy of independent variates associated with structural anomaly detection was calculated.

RESULTS

A total of 1442 women with twin pregnancies were included. In 40 women and 45 fetuses, structural anomalies were found. Fetal structural anomalies verified at delivery were detected in 42.5% (17/40) of affected pregnancies in the first trimester and 92.5% (37/40) of affected pregnancies when added second trimester (P = .13). The survival rate of pregnancies detected in second trimester was higher than that of pregnancies detected in first trimester (11.8% vs 65.2%). The mean value of intertwin CRL/NT discordance in cases with fetal structural anomalies was larger in monochorionic twins than dichorionic twins, but monochorionicity was not associated with structural anomalies. CRL discordance ≥10% (OR 3.1, 95%CI 1.5-6.3) and NT ≥95th centile (OR 20.0, 95%CI 9.0-44.2) were associated with fetal structural anomalies. In both dichorionic (DC) and monochorionic (MC) twins, the percentages of CRL discordance ≥10% was larger in twins with structural anomalies than those without structural anomalies (37.5% vs 13.4% in DC twins and 50.0% vs 12.5% in MC twins), and this was also true for NT ≥95th centile (31.3% vs 1.7% in DC twins and 37.5% vs 2.2% in MC twins). In the setting of CRL discordance ≥10%, 40.0% (16/40) of twins with structural anomalies were found, in which the predominant fetal structural anomalies were cardiovascular defects, abdominal wall defects, and central nervous system defects. The AUC for detecting structural anomalies by CRL discordance ≥10% was 0.63. In the setting of NT ≥95th centile, 32.5% (13/40) of twins with structural anomalies were found, in which the predominant fetal structural anomalies were cardiovascular defects, cystic hygroma, and abdominal wall defects. The AUC for detecting structural anomalies by NT ≥95th centile was 0.65.

CONCLUSIONS

The detection rate of twins with fetal structural anomalies was 42.5% per pregnancy in the first trimester. CRL discordance ≥10% and NT ≥95th centile may indicate higher risk of fetal structural anomalies in twins, but their efficacy was limited.

Trends of Selective Fetal Reduction and Selective Termination in Multiple Pregnancy, in England and Wales: a Cross-Sectional Study

Selective abortion was shown to be increasingly common in England and Wales over a 9-year period, occurring most frequently as twin to singleton reductions in the 1st trimester. We analysed the trends in selective abortion (SA) in multiple pregnancies in England and Wales between 2009 and 2018. This is a cross-sectional study looking at 1143 women with multiple pregnancies in England and Wales undergoing SA. There were a total of 1143 cases of SA between 2009 and 2018 in England and Wales, representing 0.07% of total abortions. There has been a steady increase in cases, from 90 in 2009 to 131 in 2018, with 82.3% justified under ground E of The Abortion Act 1967. The majority of SAs were carried out at 13-19 weeks gestation, and intracardiac injection of potassium chloride was the most prevalent method (75%). Twin to singleton reductions accounted for 59%, the most common form of SAs. Over half of all cases (59%) were performed in women aged 30-39 years, and 84% of all women were of White ethnicity. SA has been an option available for couples diagnosed with multiple pregnancy, especially when there are discordant anomalies. Although SA may decrease multiple pregnancy-related complications, preventative methods must be championed.

Epidemiology, Genetics and Epigenetics of Congenital Heart Diseases in Twins

Congenital heart defects (CHDs) refer to abnormalities in the heart function that arise at the fetal stages. It is the most common birth defect that affects 0.8% of all liveborn infants. There is an increase in the incidence of congenital heart disease in monochorionic twin gestation. A six-fold increase in CHDs exists among monochorionic twins especially in association with twin-twin transfusion syndrome (TTTS) compared to dichorionic twin pregnancy. In this review article, we discussed the epidemiology, the role of genetics like protein-coding genes, epigenetics, placenta, hemodynamics and environmental factors in the etiology of CHD in twins.

We conducted a literature search in PubMed indexed journals using the medical terms "twin pregnancy" and "congenital heart defect" to provide an overview of the uptrend in CHD in twin pregnancies, primarily due to assisted reproductive technologies (ARTs) and multiple other factors. Both the heart and placenta are vascular and share a common development window; therefore, CHD can develop secondary to placental pathologies. Among environmental factors, the strongest association of maternal smoking with CHD has been seen. We studied the causative factors to suggest improvement in echocardiographic skills in case of abnormal findings in twin gestations to decrease the CHD-associated morbidity and mortality, as early diagnosis allows doctors to precisely determine the risk of CHD. Systemic ultrasound scanning with five transverse views is very effective in diagnosing fetal CHD in twin pregnancy. In the case of genetics, prenatal counseling allows the expectant to understand the full ramifications of possible events after the pregnancy. The pathological basis of malformations specific to conjoined twinning and twin reversed arterial perfusion sequence is addressed. Also, there is evidence that folate supplementation may be protective against CHD but more research is needed to clarify the mechanisms.

We concluded from the literature that monochorionic twins are at high risk of CHD. Chorionicity seems to play a more vital role than zygosity. Even the type of heart defect in monochorial twin pregnancies was unique from single, dizygotic, or dichorionic twin pregnancies. We also emphasize improving echocardiographic skills of technicians in referring ART dichorionic twin fetuses with suspicious findings to fetal cardiologists and performing postnatal scans in the case of TTTS. To understand the role of the placenta, making use of newer technologies and examining the placenta both during pregnancy and beyond delivery will play a vital role in understanding the etiology. Even identifying early signals impacting the heart and placental vasculature and correcting them using advanced technology could downtrend the incidence in coming years. Increased maternal age as well as multiple pregnancies increasing the risk of CHD has also been implicated. For more clarity on the role of genetics, the cost of DNA sequencing needs to decrease. This will enable whole-genome sequencing in the future thus helping to discover the gene responsible for CHD ultimately proving beneficial for future generations. For environmental factors, we have to rely on observational studies to assess the risk to the unborn child. There is difficulty in studying natural factors due to the unreliability of exposure to contaminants like pesticides and air pollution.

Review of International Clinical Guidelines Related to Prenatal Screening during Monochorionic Pregnancies

We conducted a search for international clinical guidelines related to prenatal screening during monochorionic pregnancies. We found 25 resources from 13 countries/regions and extracted information related to general screening as well as screening related to specific monochorionic complications, including twin-twin transfusion syndrome (TTTS), selective fetal growth restriction (SFGR), and twin anemia-polycythemia sequence (TAPS). Findings reveal universal recommendation for the early establishment of chorionicity. Near-universal recommendation was found for bi-weekly ultrasounds beginning around gestational week 16; routine TTTS and SFGR surveillance comprised of regularly assessing fetal growth, amniotic fluids, and bladder visibility; and fetal anatomical scanning between gestational weeks 18-22. Conflicting recommendation was found for nuchal translucency screening; second-trimester scanning for cervical length; routine TAPS screening; and routine umbilical artery, umbilical vein, and ductus venosus assessment. We conclude that across international agencies and organizations, clinical guidelines related to monochorionic prenatal screening vary considerably. This discord raises concerns related to equitable access to evidence-based monochorionic prenatal care; the ability to create reliable international datasets to help improve the quality of monochorionic research; and the promotion of patient safety and best monochorionic outcomes. Patients globally may benefit from the coming together of international bodies to develop inclusive universal monochorionic prenatal screening standards.

Fetal Echocardiography for the General Pediatrician

Fetal echocardiography is now commonly used to assess fetuses for congenital heart disease. To care for their patients, it is important for the pediatrician to understand the utility of the test, the benefits, and the limitations of the results. This review outlines the indications, components, and limitations of fetal echocardiography with a focus on the care that the pediatrician provides to newborns and their families. An understanding of the fetal cardiac examination can assist the pediatrician in caring for patients with either normal or abnormal test results. The need for and timing of postnatal cardiology follow-up, and guidance on referral for fetal echocardiogram for future pregnancies are all critical roles that the pediatrician can play. Most importantly, an understanding of the limitations, including difficult-to-diagnose lesions, allows the pediatrician to maintain a high level of suspicion for cardiac defects regardless of fetal echocardiography findings. [Pediatr Ann. 2021;50(3):e121-e127.].

Live-Birth Outcomes and Congenital Malformations After Progestin-Primed Ovarian Stimulation in Maternal Endometriosis

Purpose

In patients who had advanced endometriosis, we use different protocols including GnRH agonist, GnRH antagonist and progestin-primed ovarian stimulation (PPOS) protocols to assess live-birth congenital malformations delivered after in vitro fertilization (IVF) and vitrified embryo transfer cycles.

Methods

A retrospective cohort study is conducted by us. It includes 1495 live-born infants in maternal endometriosis. From January 2010 to January 2017, we brought into infants who underwent either gonadotropin-releasing hormone agonist long protocol, gonadotropin-releasing hormone antagonist protocol or PPOS. We chose neonatal outcomes and congenital malformations as our major measures.

Results

Neonatal outcomes, as well as congenital malformations, were considered as the main measures, and gestational age, birth weight, birth length, multiple births and early neonatal death are included. All groups were comparable. The GnRH antagonist group (1.41%) and the GnRH antagonist protocol group (1.8%) had the same incidence of live-birth defects as the PPOS groups (1.33%) were similar. There were no apparent differences when it came to congenital malformations among the three groups. Multivariate logistic regression showed that infertility-time factors as well as multiple births combined to add the risk of congenital malformations; the adjusted odds were 1.143 (95% confidence interval [CI]: 0.988–1.323) and 3.253 (95% CI: 1.359–7.788). Besides, no association was found among various ovarian stimulations as well as congenital birth defect programs, maternal age, body mass index, parity or infant sex.

Conclusion

This study suggests that, in contrast to conventional ovarian stimulation, PPOS neither has any effect on neonatal outcomes in IVF adverse effects nor does it elevate the rate of congenital malformations in late endometriosis. However, randomized controlled trials of the long-term outcomes of children born after PPOS protocols for maternal endometriosis are needed and the follow-up studies were conducted to confirm this result.

Cardiac Anomalies in Liveborn and Stillborn Monochorionic Twins

BACKGROUND

Cardiovascular anomalies are more common in monochorionic twins, especially with twin-twin transfusion, compared to other twin types and to singletons. Because previous studies are based on fetal and neonatal echocardiography, more information is needed to study prevalence of cardiac anomalies in twin miscarriages, stillbirths, and children after the immediate neonatal period.

METHODS

With specific attention to cardiac anomalies, we reviewed the medical records of 335 selected liveborn twin pairs from the Marshfield Clinic Twin Cohort (enriched for twin-twin transfusion) and all twins (175 pairs) identified in the Wisconsin Stillbirth Service Program cohort of late miscarriages and stillbirths.

RESULTS

Structural cardiac defects occurred in 12% of liveborn monochorionic twin infants and 7.5% of stillborn infants with twin-twin transfusion compared to only 2% of liveborn dizygotic twins and no stillborn dizygotic infants. The most common cardiac lesion in liveborn twins was ventricular septal defect, which was usually isolated and discordant, preferentially affecting the smaller twin in monochorionic pairs. Among stillborn and miscarried monochorionic twins, the most common cardiac lesion was acardia.

CONCLUSIONS

Monochorionic twins, particularly those with TTT, are at increased risk for a spectrum of structural cardiac malformations which we suggest may be related to asymmetry of the inner cell mass resulting in a smaller poorly perfused twin. In severe cases, limited cardiac and circulatory development in the affected twin leads to acardia. In less severe cases, the smaller infant has deficient septal growth that sometimes results in ventricular septal defect.

Placental DNA methylation changes in detection of tetralogy of Fallot

OBJECTIVES

To determine whether the methylation level of cytosine nucleotides in placental DNA can be used to predict tetralogy of Fallot (TOF) and provide insights into the developmental mechanism of this condition.

METHODS

Tissue sections were obtained from formalin-fixed paraffin-embedded specimens of placental tissue obtained at birth from eight cases with non-chromosomal, non-syndromic TOF and 10 unaffected newborns. The Illumina Infinium HumanMethylation450 BeadChip assay was used to measure cytosine ('CpG' or 'cg') methylation levels at loci throughout the placental genome. Differential methylation was assessed by comparing the β-values (a measure of the extent of cytosine methylation) for individual CpG loci in fetuses with TOF vs in controls. The most discriminating CpG sites were determined based on a preset cut-off of ≥ 2.0-fold change in the methylation level. The predictive accuracy of CpG loci with significant methylation changes for TOF was determined by the area under the receiver-operating-characteristics curve (AUC). A false-discovery-rate (FDR) P-value < 0.05 was used to define a statistically significant difference in the methylation level. Ingenuity Pathway Analysis (IPA) (Qiagen) was used to identify gene pathways that were significantly overexpressed, and thus altered, in TOF cases compared with controls.

RESULTS

We found a total of 165 significantly differentially methylated CpG loci in TOF cases compared with controls, in 165 separate genes. These biomarkers demonstrated from fair to excellent individual predictive accuracy for TOF detection, with AUCs ≥ 0.75 (FDR P-value < 0.001 for all). The following CpG loci (gene) had the highest predictive accuracy: cg05273049 (ARHGAP22; AUC = 1.00; 95% CI, 1.00-1.00), cg02540011 (CDK5; AUC = 0.96; 95% CI, 0.87-1.00), cg08404201 (TRIM27; AUC = 0.95; 95% CI, 0.84-1.00) and cg00687252 (IER3; AUC = 0.95; 95% CI, 0.84-1.00). IPA revealed over-representation (dysregulation) of 14 gene pathways involved in normal cardiac development, including cardiomyocyte differentiation via bone morphogenetic protein receptors, cardiac hypertrophy signaling and role of nuclear factor of activated T cells in cardiac hypertrophy. Cardiac hypertrophy is an important feature of TOF.

CONCLUSIONS

Analysis of placental DNA cytosine methylation changes yielded accurate markers for TOF detection and provided mechanistic information on TOF development. Our work appears to confirm the central role of epigenetic changes and of the placenta in the development of TOF. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Chromosomal abnormalities detected by karyotyping and microarray analysis in twins with structural anomalies

OBJECTIVES

To evaluate the incidence and types of chromosomal abnormalities detected in twins with structural anomalies and compare their distribution according to chorionicity and amnionicity and by structural-anomaly type. The added value of chromosomal microarray analysis (CMA) over conventional karyotyping in twins was also estimated.

METHODS

This was a single-center, retrospective analysis of 534 twin pregnancies seen over an 11-year period, in which one or both fetuses were diagnosed with congenital structural anomalies on ultrasound. The ultrasound findings and invasive prenatal diagnostic results were reviewed. Twin pregnancies were categorized as monochorionic monoamniotic (MCMA), monochorionic diamniotic (MCDA) or dichorionic diamniotic (DCDA). Chromosomal abnormalities detected by G-banding karyotyping and/or CMA were analyzed by chorionicity and amnionicity and by structural-anomaly type.

RESULTS

The 534 twin pairs analyzed comprised 25 pairs of MCMA, 112 pairs of MCDA and 397 pairs of DCDA twins. Of the 549 fetuses affected by structural anomalies, 432 (78.7%) underwent invasive prenatal testing and cytogenetic results were obtained. The incidence of overall chromosomal abnormalities in the DCDA fetuses (25.4%) was higher than that in the MCMA (3.7%) and MCDA (15.3%) fetuses. The incidence of aneuploidy was significantly higher in the DCDA group (22.8%) than in the MCMA (0.0%) and MCDA (12.4%) groups. The incidence of chromosomal abnormalities detected in fetuses, with anomalies of the cardiovascular, faciocervical, musculoskeletal, genitourinary and gastrointestinal systems, was higher in the DCDA group than in the MCDA group. In both the DCDA and MCDA groups, hydrops fetalis was associated with the highest incidence of chromosomal abnormality; of these fetuses, 67.6% had Turner syndrome (45,X). Pathogenic copy-number variations (CNVs) undetectable by karyotyping were identified by CMA in five (2.0%; 95% CI, 0.3-3.7%) DCDA fetuses. No pathogenic CNVs were found in MCMA and MCDA twins.

CONCLUSIONS

Dichorionic twins with structural anomalies have a higher risk of chromosomal abnormalities, especially aneuploidies, than do monochorionic twins. The incremental diagnostic yield of CMA over karyotyping seems to be lower (2.0%) in twins than that reported in singleton pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Fetal and Neonatal Circulatory Disorders in Twin to Twin Transfusion Syndrome (The Secondary Publication)

Twin to twin transfusion syndrome (TTTS) is a major complication of monochorionic diamniotic (MD) twins, and its onset is known to be associated with placental vascular anastomoses and blood flow imbalance. In a typical case of TTTS, the recipient develops polyhydramnios, weight gain, cardiomegaly and hydrops fetalis in the uterus. In contrast, the donor develops oligohydramnios and intrauterine growth restriction. Recently, the significance of the renin-angiotensin-aldosterone system (RAAS) that transfers from the donor to the recipient has attracted interest in the fetal circulation of TTTS. The donor has decreased renal blood flow due to decreased circulating blood volume. For this reason, the secretion of RAAS hormones is augmented in the fetal kidneys of the donor. In TTTS, these RAAS hormones from the donor transfer to the recipient through the anastomosed vessels. In addition to excess preload, the recipient heart is exposed to excess afterload due to systemic vasoconstriction through RAAS hormones. Commonly occurring complications in the recipient include myocardial hypertrophy, atrioventricular valve regurgitation, and pulmonary valve stenosis or pulmonary atresia. Fetoscopic laser photocoagulation (FLP) has been introduced recently because neither mortality nor neurological morbidity have been satisfactorily improved with conventional treatment. FLP is a curative method that may improve the prognosis of TTTS. In Japan, this procedure has been performed frequently, and positive neurological outcomes have been achieved.

Dispelling Myths about Antenatal TAPS: A Call for Action for Routine MCA-PSV Doppler Screening in the United States

In the United States, routine middle cerebral artery peak systolic velocity (MCA-PSV) Doppler screening for the detection of antenatal twin anemia-polycythemia sequence (TAPS) is not recommended. The current and only national clinical guideline from the highly-influential Society for Maternal-Fetal Medicine states that, “There is no evidence that monitoring for TAPS with MCA PSV Doppler at any time, including > 26 weeks, improves outcomes, so that this additional screening cannot be recommended at this time.” We argue this recommendation has disproportionate influence on patients and the care they are offered and receive. We use current evidence to highlight and dispel pervasive myths surrounding antenatal TAPS and the value of routine MCA-PSV screening. An ethical framework that illustrates the importance of giving patients the opportunity for routine screening is presented. Findings demonstrate that: (1) both spontaneous and post-laser TAPS is a serious, potentially life-threatening complication, (2) treatment for TAPS is effective and includes expectant management, intrauterine transfusion (IUT), or surgery, (3) and routine MCA-PSV, which has satisfactory diagnostic accuracy, is currently the only way to provide early detection of TAPS. We conclude that routine TAPS screening is a medically proven valuable resource that should be offered to patients in need and to the clinicians who are trying to act toward their benefit.

Congenital Heart Defects in Monochorionic Twins: A Systematic Review and Meta-Analysis

Monochorionic (MC) twins are at an increased risk of developing congenital heart defects (CHDs) compared to singletons and dichorionic twins. The development of acquired CHDs in this specific group of twins is associated with twin-twin transfusion syndrome (TTTS). We performed a systematic review and meta-analysis to provide an overview of the reported birth prevalence of CHDs in liveborn MC twins with and without TTTS. Twelve studies were included in this review. Compared to the reference population, MC twins were 6.3 times more likely to be born with a CHD (59.3 per 1000 liveborn twins; relative risk (RR) 6.3; 95% confidence interval (CI): 4.4-9.1), and TTTS twins had a 12-fold increased risk of having a CHD at birth (87.3 per 1000 live births; RR 12.4, 95% CI: 8.6-17.8). The increased incidence of CHDs can mainly be attributed to the risk of right ventricular outflow tract obstruction (35/1000 TTTS twin live births vs. 0.5/1000 singleton live births). We recommend an expert fetal echocardiogram in all MC twins, follow-up scans in the event of TTTS, and a postnatal cardiac evaluation in all TTTS survivors.

EPAS 1, congenital heart disease, and high altitude: disclosures by genetics, bioinformatics, and experimental embryology

The high-altitude environment is a challenge for human settlement. Low oxygen concentrations, extreme cold, and a harsh arid climate are doubtlessly challenges for the colonization of the Tibetan plateau. I am delighted to comment on the article of Pan et al. (2018) on mutations in endothelial PAS domain-containing protein 1 (EPAS1) in congenital heart disease in Tibetans. In humans, the EPAS1 gene is responsible for coding EPAS1 protein, an alias of which is HIF2α, an acronym for hypoxia-inducible factor 2 alpha. EPAS1 is a type of hypoxia-inducible factors, which are collected as a group of transcription factors involved in body response to oxygen level. EPAS1 gene is active under hypoxic conditions and plays an essential role in the development of the heart and in the management of the catecholamine balance, mutations of which have been identified in neuroendocrine tumors. In this article, Pan et al. investigated Tibetan patients with and without non-syndromic congenital heart disease. They identified two novel EPAS1 gene mutations, of which N203H mutation significantly affected the transcription activity of the vascular endothelial growth factor (VEGF) promoter, particularly in situations of hypoxia. VEGF is a downstream target of HIF-2 (other than HIF-1), and the expression levels of either HIF-1α or HIF-2α correlate positively to VEGF expression. Pan et al.'s data may be of incitement to further evaluate protein-protein interaction and using experimental animal models. Moreover, it may also be a stimulus for setting up genetic epidemiologic studies for other populations living at high altitudes.

Placental epigenetics for evaluation of fetal congenital heart defects: Ventricular Septal Defect (VSD)

Ventricular Septal Defect (VSD), the most common congenital heart defect, is characterized by a hole in the septum between the right and left ventricles. The pathogenesis of VSD is unknown in most clinical cases. There is a paucity of data relevant to epigenetic changes in VSD. The placenta is a fetal tissue crucial in cardiac development and a potentially useful surrogate for evaluating the development of heart tissue. To understand epigenetic mechanisms that may play a role in the development of VSD, genome-wide DNA methylation assay on placentas of 8 term subjects with isolated VSD and no known or suspected genetic syndromes and 10 unaffected controls was performed using the Illumina HumanMethylation450 BeadChip assay. We identified a total of 80 highly accurate potential CpGs in 80 genes for detection of VSD; area under the receiver operating characteristic curve (AUC ROC) 1.0 with significant 95% CI (FDR) p-values < 0.05 for each individual locus. The biological processes and functions for many of these differentially methylated genes are previously known to be associated with heart development or disease, including cardiac ventricle development (HEY2, ISL1), heart looping (SRF), cardiac muscle cell differentiation (ACTC1, HEY2), cardiac septum development (ISL1), heart morphogenesis (SRF, HEY2, ISL1, HEYL), Notch signaling pathway (HEY2, HEYL), cardiac chamber development (ISL1), and cardiac muscle tissue development (ACTC1, ISL1). In addition, we identified 8 microRNAs that have the potential to be biomarkers for the detection of VSD including: miR-191, miR-548F1, miR-148A, miR-423, miR-92B, miR-611, miR-2110, and miR-548H4. To our knowledge this is the first report in which placental analysis has been used for determining the pathogenesis of and predicting VSD.

[Perinatal issues of biamniotic twin pregnancies depending on gestational ages of selective termination]

OBJECTIVES

A severe fetal abnormality is found in 1-2% of biamniotic twin gestations leading to the dilemma of expectative management or selective termination of the defective fetus. The primary objective of our study was to determinate the relationship between perinatal outcomes and gestational ages of selective termination.

METHODS

We conducted a single-center retrospective and observational study which reviewed 58 biamniotic twin pregnancies that underwent selective termination for discordant fetal anomalies between January 2006 and September 2017. Fetal anomalies, ages of diagnostic and selective termination, perinatal outcomes were noted.

RESULTS

Selective terminations realised before 20 weeks (group A) were complicated by 8,7% of fetal loss and 28,6% of prematurity, of which 14,3% before 32 GA. In group B (selective termination planned between 20 and 32 weeks), there was no fetal loss but 40% of prematurity of which 13,3% before 32 GA. In group C (selective termination planned after 32 weeks), there was no fetal loss, but 42,1% of prematurity, and one birth before 32 GA (5%).

CONCLUSIONS

Gestational age of a selective termination should be determined together with the parents, after informing them about the risks and technical difficulties at each gestational age.

The burden to be second twin: a population-based study of 2686 twins: (2124 dichorionic). Proposal of the concept of mobility

Objectives: To identify if there is a specific neonatal morbidity/mortality among second twins relative to first twins.Study design: A 17-year (2001-2017) population-based observational cohort of all twin newborns born in the South of Reunion island after 21 weeks.Results: Among 1062 dichorionic (DTP) and 281 monochorionic twin pregnancies (2686 newborns), twin 2 have a doubled risk to be in breech presentation and a bad Apgar at 1 mn (≤6) in vaginal deliveries. Specific to dichorionic pregnancies, twin 2 were lighter by 50-60 g than twin 1, had higher rates of intrauterine growth retardation (IUGR), OR 1.33, p = .007, a doubled risk to have congenital abnormalities OR 2.1, p = .006.Conclusion: In dichorionic twin pregnancies, second twins having a doubled prevalence of severe congenital abnormalities are not completely elucidated and deserves further research. (1) We propose that twin 2 presenting higher risks of being IUGR and much higher risks of severe malformations suggest that during pregnancy, the less mobile of the two twins is "relegated" to the back of the uterus. (2) For interventions in the delivery room, systematically the most experimented neonatologist should plan to manage the second twin because significantly twin 2 presents higher problems than twin 1.

Effect of Maternal Advanced Endometriosis on Risk of Congenital Malformations for Infants Born After in vitro Fertilization and Frozen-Thawed Embryo Transfer: Analysis of 28,600 Newborns

Background: Endometriosis is one of the most challenging diseases for doctors helping infertile women conceive, which has become a common method to help maternal endometriosis-associated infertility. Women with advanced endometriosis possess a higher risk of several adverse outcomes both during pregnancy and at the time of delivery. Whether endometriosis gives rise to a higher occurrence of congenital abnormalities in infants via in vitro fertilization and frozen-thawed embryo transfer (IVF-ET) remains unknown. Methods: Data collected on 22,865 women undergoing IVF using a freeze-all strategy from 2007 to 2017 were analyzed to estimate the rate of congenital malformations. We used an adjusted OR to compare the fertility outcomes of women with advanced endometriosis to the control group. Results: We studied 1,495 infants born from women with advanced endometriosis and 27,105 infants born from endometriosis-free women. There was a 1.557-fold risk that the infants with advanced maternal endometriosis would develop a congenital malformation (adjusted OR: 1.557, 95% CI: 1.03-2.35). Compared with singletons, twins were 1.957 times more likely to experience an adverse outcome (OR: 1.957, 95% CI: 1.561-2.455). When analyzing specific categories of birth defects, the proportion of circulatory system defects was higher than the other categories of birth defects in total (0.56%), followed by musculoskeletal system defects (0.15%). Conclusions: Maternal advanced endometriosis might increase the risk of congenital malformations for infants born after IVF-ET. The organ system most frequently affected by congenital malformations was the cardiovascular system, followed by the musculoskeletal system.

In Utero Diagnoses of Strikingly Similar Presentations of Complete Atrioventricular Septal Defects in a Pair of Dizygotic Twins Concordant for Trisomy 21

Trisomy 21, or Down syndrome (DS), is a genetic disorder affecting approximately 1 in 500–750 live births. The prevalence of DS has increased over the past two decades, correlating with a rise in the proportion of pregnancies complicated by advanced maternal age. There is also a correlation between advanced maternal age and dizygotic twinning rates. There is an increased risk of at least one twin being affected in dizygotic pregnancies compared to singletons. However, despite this greater relative risk, reports of concordance of DS in both dizygotic twins are very rare. Congenital heart disease (CHD) occurs in roughly 40% of individuals with DS, but there can be considerable phenotypic variation. The most common, atrioventricular septal defect accounts for only 40% of CHD seen in DS. There is also a higher incidence of CHD in twins, but also with a low incidence of concordance. There have been only five reported cases of concordant DS in dizygotic twins with confirmed chromosomal analyses; none of which describe concordant congenital heart disease. Here, we describe an unusual case of dizygotic twins of differing genders concordant for both Down syndrome and congenital heart disease of a strikingly similar presentation.

Copy Number Variants and Exome Sequencing Analysis in Six Pairs of Chinese Monozygotic Twins Discordant for Congenital Heart Disease

Congenital heart disease (CHD) is one of the most common birth defects. More than 200 susceptibility loci have been identified for CHDs, yet a large part of the genetic risk factors remain unexplained. Monozygotic (MZ) twins are thought to be completely genetically identical; however, discordant phenotypes have been found in MZ twins. Recent studies have demonstrated genetic differences between MZ twins. We aimed to test whether copy number variants (CNVs) and/or genetic mutation differences play a role in the etiology of CHDs by using single nucleotide polymorphism (SNP) genotyping arrays and whole exome sequencing of twin pairs discordant for CHDs. Our goal was to identify mutations present only in the affected twins, which could identify novel candidates for CHD susceptibility loci. We present a comprehensive analysis for the CNVs and genetic mutation results of the selected individuals but detected no consistent differences within the twin pairs. Our study confirms that chromosomal structure or genetic mutation differences do not seem to play a role in the MZ twins discordant for CHD.

Congenital heart defects according to the types of the risk factors - a single center experience

Objective: The main aim of this study was to compare the prevalence of congenital heart defects (CHDs) between pregnant women with and those without the risk factors. The secondary aim was to determine the influence of the specific risk factors, divided into subgroups, on the development of the CHD. Methods: The presented results were obtained over the course of a 15-year study between years 2002 and 2016. Fetal echocardiography was performed as a planned screening examination during the second trimester of gravidity. A total of 35,831 singleton pregnancies were examined at our center. Risk factors for the development of CHDs were analyzed and divide into the following groups: (i) maternal age ≥35 years; (ii) mother-related risk factors; (iii) pregnancy- and fetus-related risk factors; (iv) pregnancy after in vitro fertilization (IVF); (v) history of CHDs in the first-degree family member; (vi) history of CHDs in the second-degree family member; and (vii) positive genetic family history. Results: The risk factors were identified in 25% (8990/35,831) of pregnancies. In total, CHDs were detected in 1.1% (394/35,831) of fetuses. The prevalence rate of CHDs was higher in the pregnancies with than in those without the risk factors (2.5% [221/8990] versus 0.6% [173/26,841]; p < .0001). The presence of pregnancy- and fetus-related risk factors (odds ratio [OR], 6.5; 95% confidence interval [CI], 4.3-9.7) and pregnancy after IVF (OR, 2.8; 95% CI, 1.5-5.2) were found to be independent risk factors of CHDs. Conclusions: The presence of specific risk factors is related to the increasing prevalence of CHDs. Pregnancy- and fetus-related risk factors and in vitro fertilization were found to be the independent risk factors of CHD.

Recipient Twin Circular Shunt Physiology Before Fetal Laser Surgery: Survival and Risks for Postnatal Right Ventricular Outflow Tract Obstruction

OBJECTIVES

To evaluate risk for congenital heart disease (CHD) in recipient twins with circular shunt physiology (CSP).

METHODS

This prospective study enrolled twin-twin transfusion syndrome (TTTS) cases from 2006 to 2015. Fetal echocardiography (FE) was performed before laser surgery when cardiac involvement was suspected. Diagnosis of recipient twin CSP required tricuspid and pulmonary regurgitation, right ventricular dysfunction, and flow reversal in the ductus arteriosus. Outcomes were assessed at 30 days after birth.

RESULTS

Of the 496 TTTS pregnancies, 20 (4%) met the criteria for CSP. Among those born alive, who had documented cardiac outcomes (n = 457), patients with CSP were more likely to have CHD, specifically right ventricular outflow tract obstruction (5 of 18 [27.8%] versus 22 of 439 [5.0%], odd ratio [OR] 7.29, 95% confidence interval [CI] 2.05-24.72, P = .0025). Of the recipient twins with preoperative FE (n = 259, 52%) who were born alive and had documented cardiac outcomes (n = 242), those with CSP were still more likely to have right ventricular outflow tract obstruction (5 of 18 [27.8%] versus 14 of 224 [6.3%], OR 5.77, CI 1.54-20.92, P = .0077). With both analyses, twins with CSP had higher Quintero stage, but similar patient characteristics and 30-day mortality compared with those without CSP. Subgroup analyses of the CSP cohort identified no differences in preoperative characteristics or FE findings predictive of CHD.

CONCLUSIONS

Recipient twins with preoperative CSP were at increased risk for postnatal right ventricular outflow tract obstruction, but appeared to have comparable survival after fetal laser surgery despite these dramatic pathophysiological prenatal findings. Preoperative FE in TTTS remains important for prediction of postnatal CHD.

Comparison of Late Mortality Among Twins Versus Singletons With Congenital Heart Defects

In 2014, in the United States, nearly 7% of newborns were twins. Congenital heart defects (CHDs) are more frequent in both monozygotic and dizygotic twins than in singletons. Still, the longer-term prognosis for CHD twins is unknown. Here we assess the mortality pattern for CHD twins up to age 36 years and compare it with that for non-CHD twins, non-CHD co-twins, and CHD singletons. We identified all twins and a 5% random sample of all singletons born in Denmark from 1977 to 2009 by linking Danish national population and health registers. CHD cases were defined as subjects having a primary inpatient diagnosis of CHD (excluding preterm ductus) within the first year of life, and mortality was assessed through 2013. Among 63,362 live-born twin individuals, a total of 373 twins (0.59%) had a CHD diagnosis, whereas the corresponding numbers for singletons were 383 of 98,647 (0.39%). During the follow-up, 82 (22.0%) CHD twins died compared with 91 (23.8%) CHD singletons (p = 0.56). Despite a 5 times higher proportion of prematurity, CHD twins had a tendency toward only a moderately increased neonatal mortality compared with CHD singletons (hazard ratio 1.5, 95% confidence interval 0.94 to 2.5), and after the neonatal period up to age 36 the tendency was reversed (hazard ratio 0.8, 95% confidence interval 0.5 to 1.2). A potential underlying mechanism for this mortality pattern is selective intrauterine and neonatal mortality of twins with the most severe CHD. In conclusion, the study indicates that the overall survival prognosis for CHD twins is similar to that of CHD singletons.

Risk Factors for Birth Defects

Importance

Major congenital abnormalities, or birth defects, carry significant medical, surgical, cosmetic, or lifestyle consequences. Such abnormalities may be syndromic, involving multiple organ systems, or can be isolated. Overall, 2% to 4% of live births involve congenital abnormalities. Risk factors for birth defects are categorized as modifiable and nonmodifiable. Modifiable risk factors require thorough patient education/counseling. The strongest risk factors, such as age, family history, and a previously affected child, are usually nonmodifiable.

Objective

This review focuses on risk factors for birth defects including alcohol consumption, illicit drug use, smoking, obesity, pregestational diabetes, maternal phenylketonuria, multiple gestation, advanced maternal age, advanced paternal age, family history/consanguinity, folic acid deficiency, medication exposure, and radiation exposure.

Evidence Acquisition

Literature review via PubMed.

Results

There is a strong link between alcohol use, folic acid deficiency, obesity, uncontrolled maternal diabetes mellitus, uncontrolled maternal phenylketonuria, and monozygotic twins and an increased risk of congenital anomalies. Advanced maternal age confers an increased risk of aneuploidy, as well as nonchromosomal abnormalities. Some medications, including angiotensin converting enzyme inhibitors, retinoic acid, folic acid antagonists, and certain anticonvulsants, are associated with various birth defects. However, there are few proven links between illicit drug use, smoking, advanced paternal age, radiation exposure, and statins with specific birth defects.

Conclusions and Relevance

Birth defects are associated with multiple modifiable and nonmodifiable risk factors. Obstetrics providers should work with patients to minimize their risk of birth defects if modifiable risk factors are present and to appropriately counsel patients when nonmodifiable risk factors are present.

Clinical aspects of prenatally detected congenital heart malformations and the yield of chromosomal microarray analysis

OBJECTIVE

The yield of chromosomal microarray analysis (CMA) for prenatally detected congenital heart defects (CHD) is 6.6% to 19.2%. We evaluated the yield of CMA in cases of prenatally detected CHD in regard to specific clinical characteristics.

METHODS

Data from 192 cases of CHD including type, clinical and familial background, workup performed during the pregnancy, and pregnancy outcomes were collected.

RESULTS

Fetal echocardiography was performed in all cases; 61.4% of CHD were suspected by ultrasound. There was a positive family history (FH) in 15.7%. Abnormal nuchal translucency or umbilical cord anomalies were detected in 1.7% and 5.9%, respectively, and 55.1% were isolated cases. In 11 of 96 cases in which genetic testing was performed, karyotype and CMA were abnormal (11.5%). The detection rate of CMA (performed in 72 cases) was 9.7%. The yield of CMA was similar in simple cases, isolated cases, and cases with a positive FH. CMA was abnormal in 7.3% of ventricular septal defect cases.

CONCLUSION

Most cases of prenatally detected CHD had no additional extra-cardiac, sonographic findings suggesting increased risk for CHD. The yield of CMA testing was significant in all clinical scenarios including simple heart malformations, isolated cases, and cases with a positive FH. © 2016 John Wiley & Sons, Ltd.

Congenital heart disease in twins: The contribution of type of conception and chorionicity

BACKGROUND

Increased incidence of congenital heart disease (CHD) has been reported in the offspring of monochorionic twin gestations. Assisted reproductive technology (ART), which is related to increased rates of twinning, has also been associated with higher risk of birth defects. We studied the incidence of CHD in a cohort of twins to clarify the contribution of type of conception and chorionicity.

METHODS

Data concerning 874 live-born twins of which at least one was admitted in our Neonatal Unit during 1995-2012 were analysed. Forty-five % (N=197) of the gestations resulted from ART (in vitro fertilisation or intracytoplasmic sperm insertion).

RESULTS

In the ART group 32/389 (8.2%) had CHD compared to 21/485 (4.3%) infants conceived naturally (OR 1.90, 95%CI 1.08-3.34, p=0.024). Spontaneous-conception gestations had higher incidence of monochorionic placentation (47/245 versus 4/197, p<0.001), and included younger mothers (29.1±5.2 versus 33.9±5.5years, p<0.001) who had higher parity (median 2 [range 1-7] versus 1 Pinborg (2005), Blondel and Kaminski (2002), Knopman et al. (2014), Kyvik and Derom (2006) ; p<0.001). Multivariable logistic regression analysis showed that ART (OR 2.60, 95% CI 1.24-5.45) and monochorionicity (OR 3.49, 95% CI 1.57-7.77) were significant determinants of CHD, independently of maternal age, parity, and the gender of the offspring.

CONCLUSIONS

We confirmed that monochorionic twins have increased risk of CHD and we documented a higher incidence of CHD in ART twins independently of chorionicity. We suggest improvement of echocardiographic skills of health care professionals involved in prenatal screening and foetal cardiology referral of ART dichorionic twins with suspicious findings at screening, in addition to all monochorionic gestations.