Analysis of selected maternal exposures and non-syndromic atrioventricular septal defects in the National Birth Defects Prevention Study, 1997-2005

Meta-analysis of risk factors for congenital heart disease - part 2: maternal medication, reproductive technologies, and familial and fetal factors

BACKGROUND

The quantitative effects of congenital heart disease (CHD) risk factors are not fully understood. We conducted a meta-analysis of all CHD risk factors. This report explores maternal medication, assisted reproductive technologies (ART), and familial and fetal factors.

METHODS

Relevant studies were identified using a search strategy encompassing the concepts of CHD and prenatal risk factors with the following inclusion criteria: (1) peer-reviewed articles, (2) quantifying the effects of CHD risk factors, (3) between 1989 and 2022. Pooled odds ratios (OR) and 95% confidence interval (CI) were calculated using a random effect model.

RESULTS

131 articles met the inclusion criteria. Associations were found between CHDs and extracardiac anomalies (OR 3.41, 95% CI 1.72-6.77), increased nuchal translucency (OR 6.87, 95% CI 2.42-19.53), family history of CHD (OR 2.90, 95% CI 2.25-3.75), maternal antidepressants (OR 1.23, 95% CI 1.09-1.38) and antihypertensives (OR 2.07, 95% CI 1.80-2.38). A positive association was observed between severe CHDs and lithium, but with a very wide CI encompassing the null effect. A positive association was observed between severe CHDs and ARTs (OR 1.98, 95% CI 1.30-3.02). The data were insufficient for anomalies of the umbilical cord, anticonvulsants and retinoid medication.

CONCLUSION

There were strong associations between CHDs and increased nuchal translucency, extracardiac anomalies and family history of CHD. Effect sizes were modest for maternal medication and ART. Data was scarce and sometimes inconclusive for some risk factors commonly cited as being associated with CHD, such as lithium, anomalies of the umbilical cord, anticonvulsants, and retinoid medication.

Systematic Review and Meta-analysis of Prenatal Risk Factors for Congenital Heart Disease: Maternal Chronic Diseases and Parental Exposures

BACKGROUND

There is considerable heterogeneity in studies on prenatal risk factors for congenital heart diseases (CHDs). We performed a meta-analysis of all nongenetic factors of CHDs. This report presents results of factors related to maternal chronic diseases and parental exposures.

METHODS

A systematic search encompassing concepts of CHD and risk factors was used, using the following inclusion criteria: (1) original peer-reviewed articles, (2) quantifying the effects of risk factors for CHDs, (3) between 1989 and 2022. Pooled odds ratios (ORs) and 95% confidence interval (CI) were calculated using a random-effect model.

RESULTS

Inclusion criteria were met for 170 studies. There was an association between being overweight or obese and CHDs (OR, 1.26; 95% CI, 1.15-1.37), with a dose-effect relationship. Pregestational diabetes (PGDM) was associated with CHDs (OR, 3.51; 95% CI, 2.86-4.3), without difference between type 1 and type 2 PGDM. The effect size of gestational diabetes was less than that of PGDM (OR, 1.38; 95% CI, 1.18-1.61). There was an association between CHDs and pre-eclampsia (OR, 2.01; 95% CI, 1.32-3.05), paternal smoking (OR, 1.32; 95% CI, 1.03-1.70), and alcohol use (OR, 1.50; 95% CI, 1.08-2.08). A smaller association was found with maternal smoking and advanced maternal age.

CONCLUSIONS

There exists robust evidence for increased risk of CHD in the presence of obesity, maternal diabetes, maternal smoking, and increased maternal age. The effect sizes were relatively modest, except for PGDM. The robustness of the evidence decreased when CHDs were divided into subgroups or when the analyses were restricted to severe CHDs.

Epigenetic Evaluation of the TBX20 Gene and Environmental Risk Factors in Mexican Paediatric Patients with Congenital Septal Defects

The TBX20 gene has a key role during cardiogenesis, and it has been related to epigenetic mechanisms in congenital heart disease (CHD). The purpose of this study was to assess the association between DNA methylation status and congenital septal defects. The DNA methylation of seven CpG sites in the TBX20 gene promoter was analyzed through pyrosequencing as a quantitative method in 48 patients with congenital septal defects and 104 individuals with patent ductus arteriosus (PDA). The average methylation was higher in patients than in PDA (p < 0.001). High methylation levels were associated with a higher risk of congenital septal defects (OR = 4.59, 95% CI = 1.57-13.44, p = 0.005). The ROC curve analysis indicated that methylation of the TBX20 gene could be considered a risk marker for congenital septal defects (AUC = 0.682; 95% CI = 0.58-0.77; p < 0.001). The analysis of environmental risk factors in patients with septal defects and PDA showed an association between the consumption of vitamins (OR = 0.10; 95% CI = 0.01-0.98; p = 0.048) and maternal infections (OR = 3.10; 95% CI = 1.26-7.60; p = 0.013). These results suggest that differences in DNA methylation of the TBX20 gene can be associated with septal defects.

Congenital anomalies and maternal age: A systematic review and meta-analysis of observational studies

INTRODUCTION

Several studies have reported on the maternal age-associated risks of congenital anomalies. However, there is a paucity of studies with comprehensive review of anomalies. We aimed to quantify the risk of birth defects in children born to middle-aged mothers compared with that in children born to young or older mothers.

MATERIAL AND METHODS

We classified maternal ages into three groups: young (<20 years old), middle (20-34 years old) and older age (≥35 years old). Observational studies that met our age criteria were eligible for inclusion. The articles searched using the Embase and MEDLINE databases were those published from 1989 to January 21, 2021. The Newcastle-Ottawa scale was used to assess the risk of bias. If heterogeneity exceeded 50%, the random effect method was used; otherwise, the fixed-effect method was used. Prospero registration number: CRD42021235229.

RESULTS

We included 15 cohort, 14 case-control and 36 cross-sectional studies. The pooled unadjusted odds ratio (95% CI) of any congenital anomaly was 1.64 (1.40-1.92) and 1.05 (0.95-1.15) in the older and young age groups, respectively (very low quality of evidence). The pooled unadjusted odds ratio of chromosomal anomaly was 5.64 (5.13-6.20) and 0.69 (0.54-0.88) in the older and young age groups, respectively. The pooled unadjusted odds ratio of non-chromosomal anomaly was 1.09 (1.01-1.17) and 1.10 (1.01-1.21) in the older and young age groups, respectively (very low quality of evidence). The incidence of abdominal wall defects was increased in children of women in the young maternal age group.

CONCLUSIONS

We identified that very low quality evidence suggests that women in the older maternal age group had increased odds of having children with congenital anomalies compared with those in the 20-34 year age group. There was no increase in odds of children with congenital anomalies in women of <20 year age group except for abdominal defects compared with those in the 20-34 year age group. The results stem from very low quality evidence with no adjustment of confounders.

Cooking stoves and risk of congenital heart disease in Northwest China: A case-control study

Congenital heart disease (CHD) has become the most common birth defect in recent decades. The aim of our study was to examine the association between stove cooking by women during pregnancy and congenital heart disease in their offspring. To address this question, we conducted a case-control study from 2014 to 2016 in Xi'an, Shaanxi, Northwest China, investigating 326 cases and 1071 controls. The cases included fetuses or newborns diagnosed with CHD based on the International Classification of Disease (ICD)-10. Controls consisted of healthy newborns without birth defects. Multivariate unconditional logistic regression was applied to analyze the effects of stove cooking before and during pregnancy on CHD in offspring. After adjusting for confounding factors, we found that, compared to cooking with gas stoves, electromagnetic, coal, and firewood stoves during pregnancy was associated with increased risk of CHD in offspring [electromagnetic stove (odds ratio (OR): 2.89, 95% confidence interval (CI): 2.02, 4.12); coal stove (OR: 3.94, 95% CI: 2.33, 6.65); firewood stove (OR: 6.74, 95% CI: 3.03, 15.00)]. Additionally, higher cooking frequency was associated with increased risk of CHD [total stoves (OR: 2.27, 95% CI: 1.57, 3.28); gas stove (OR: 2.38, 95% CI: 1.43, 3.95); electromagnetic stove (OR: 2.46, 95% CI: 1.32, 4.58); coal and firewood stoves (OR: 3.09, 95% CI: 1.01, 9.46)]. Our study suggests that using electromagnetic, coal, and firewood stoves for cooking during pregnancy and greater cooking frequency increased the risk of CHD in offspring. More attention to the choice of fuels in cooking by pregnant women would help to reduce the incidence of CHD in children.

Association of MTHFD1 gene polymorphisms and maternal smoking with risk of congenital heart disease: a hospital-based case-control study

Background

MTHFD1 gene may affect the embryonic development by elevated homocysteine levels, DNA synthesis and DNA methylation, but limited number of genetic variants of MTHFD1 gene was focused on the association with congenital heart disease (CHD). This study examined the role of MTHFD1 gene and maternal smoking on infant CHD risk, and investigated their interaction effects in Chinese populations.

Methods

A case-control study of 464 mothers of CHD infants and 504 mothers of health controls was performed. The exposures of interest were maternal tobacco exposure, single nucleotide polymorphisms (SNPs) of maternal MTHFD1 gene. The logistic regression model was used for accessing the strength of association.

Results

Mothers exposed to secondhand smoke during 3 months before pregnancy (adjusted odds ratio [aOR] = 1.56; 95% confidence interval [CI]: 1.13–2.15) and in the first trimester of pregnancy (aOR = 2.24; 95%CI: 1.57–3.20) were observed an increased risk of CHD. Our study also found that polymorphisms of maternal MTHFD1 gene at rs1950902 (AA vs. GG: aOR = 1.73, 95% CI: 1.01–2.97), rs2236222 (GG vs. AA: aOR = 2.38, 95% CI: 1.38–4.12), rs1256142 (GA vs.GG: aOR = 1.57, 95% CI: 1.01–2.45) and rs11849530 (GG vs. AA: aOR = 1.68, 95% CI: 1.02–2.77) were significantly associated with higher risk of CHD. However, we did not observe a significant association between maternal MTHFD1 rs2236225 and offspring CHD risk. Furthermore, we found the different degrees of interaction effects between polymorphisms of the MTHFD1 gene including rs1950902, rs2236222, rs1256142, rs11849530 and rs2236225, and maternal tobacco exposure.

Conclusions

Maternal polymorphisms of MTHFD1 gene, maternal tobacco exposure and their interactions are significantly associated with the risk of CHD in offspring in Han Chinese populations. However, more studies in different ethnic populations with a larger sample and prospective designs are required to confirm our findings.

Trial registration

Registration number: ChiCTR1800016635.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04419-2.

The transcription factor Sox7 modulates endocardiac cushion formation contributed to atrioventricular septal defect through Wnt4/Bmp2 signaling

Cardiac septum malformations account for the largest proportion in congenital heart defects. The transcription factor Sox7 has critical functions in the vascular development and angiogenesis. It is unclear whether Sox7 also contributes to cardiac septation development. We identified a de novo 8p23.1 deletion with Sox7 haploinsufficiency in an atrioventricular septal defect (AVSD) patient using whole exome sequencing in 100 AVSD patients. Then, multiple Sox7 conditional loss-of-function mice models were generated to explore the role of Sox7 in atrioventricular cushion development. Sox7 deficiency mice embryos exhibited partial AVSD and impaired endothelial to mesenchymal transition (EndMT). Transcriptome analysis revealed BMP signaling pathway was significantly downregulated in Sox7 deficiency atrioventricular cushions. Mechanistically, Sox7 deficiency reduced the expressions of Bmp2 in atrioventricular canal myocardium and Wnt4 in endocardium, and Sox7 binds to Wnt4 and Bmp2 directly. Furthermore, WNT4 or BMP2 protein could partially rescue the impaired EndMT process caused by Sox7 deficiency, and inhibition of BMP2 by Noggin could attenuate the effect of WNT4 protein. In summary, our findings identify Sox7 as a novel AVSD pathogenic candidate gene, and it can regulate the EndMT involved in atrioventricular cushion morphogenesis through Wnt4-Bmp2 signaling. This study contributes new strategies to the diagnosis and treatment of congenital heart defects.

Paternal genetic variants and risk of obstructive heart defects: A parent-of-origin approach

Previous research on risk factors for obstructive heart defects (OHDs) focused on maternal and infant genetic variants, prenatal environmental exposures, and their potential interaction effects. Less is known about the role of paternal genetic variants or environmental exposures and risk of OHDs. We examined parent-of-origin effects in transmission of alleles in the folate, homocysteine, or transsulfuration pathway genes on OHD occurrence in offspring. We used data on 569 families of liveborn infants with OHDs born between October 1997 and August 2008 from the National Birth Defects Prevention Study to conduct a family-based case-only study. Maternal, paternal, and infant DNA were genotyped using an Illumina Golden Gate custom single nucleotide polymorphism (SNP) panel. Relative risks (RR), 95% confidence interval (CI), and likelihood ratio tests from log-linear models were used to estimate the parent-of-origin effect of 877 SNPs in 60 candidate genes in the folate, homocysteine, and transsulfuration pathways on the risk of OHDs. Bonferroni correction was applied for multiple testing. We identified 3 SNPs in the transsulfuration pathway and 1 SNP in the folate pathway that were statistically significant after Bonferroni correction. Among infants who inherited paternally-derived copies of the G allele for rs6812588 in the RFC1 gene, the G allele for rs1762430 in the MGMT gene, and the A allele for rs9296695 and rs4712023 in the GSTA3 gene, RRs for OHD were 0.11 (95% CI: 0.04, 0.29, P = 9.16x10^-7), 0.30 (95% CI: 0.17, 0.53, P = 9.80x10^-6), 0.34 (95% CI: 0.20, 0.57, P = 2.28x10^-5), and 0.34 (95% CI: 0.20, 0.58, P = 3.77x10^-5), respectively, compared to infants who inherited maternally-derived copies of the same alleles. We observed statistically significant decreased risk of OHDs among infants who inherited paternal gene variants involved in folate and transsulfuration pathways.

Obstructive heart defects are birth defects that cause obstruction to the blood flow of the developing heart. Common OHDs include coarctation of the aorta, aortic stenosis and pulmonary stenosis. While there is a fair amount of literature indicating an association between maternal genetic variants and OHDs, less is known about the role of paternal genetic variants in the etiology of OHDs. We used a genotype clustering algorithm, SNPMClust, that was developed in-house at the Arkansas Center for Birth Defects Research and Prevention to study the role of paternal genetic variants in the folate, homocysteine and transsulfuration pathways. Maternal, paternal, and infant DNA specimens were collected from participants of the National Birth Defects Prevention Study, a large population-based case-control study in the United States, and were genotyped using an Illumina Golden Gate custom single nucleotide polymorphism (SNP) panel. We identified 4 SNPs in the folate and transsulfuration pathways, rs6812588, rs1762430, rs9296695, and rs4712023, that were associated with a statistically significant decreased risk of OHDs for infants who inherited a paternally-derived copy of the variant allele compared to infants who inherited a maternal copy of the variant allele. In conclusion, we observed a significantly decreased risk and less epigenetic influence of paternal genetic variants on OHDs compared to maternally-derived variants.

Heart Disease and Stroke Statistics-2021 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2021 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors related to cardiovascular disease.

RESULTS

Each of the 27 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Maternal folic acid supplementation mediates the associations between maternal socioeconomic status and congenital heart diseases in offspring

Low maternal socioeconomic status (SES) is considered as a risk factor of congenital heart diseases (CHDs) in offspring. However, the pathways underpinning the SES-CHDs associations are unclear. We assessed if first trimester maternal folic acid supplementation (FAS) is a mediator of the SES-CHDs associations. This case-control study included 8379 CHD cases and 6918 CHD-free controls from 40 participating centers in Guangdong, Southern China, 2004-2016. All fetuses were screened for CHDs using ultrasound and cases were confirmed by echocardiogram. We collected SES and FAS information during face-to-face interview by obstetricians using a structured questionnaire. Low SES was defined as education attainment <12 years, household individual income <3000 Chinese Yuan/person/month or unemployment. FAS referred to at least 0.4 mg of daily folic acid intake over 5 days/week continuously. We used causal mediation analysis to estimate the direct, indirect and proportion mediated by FAS on the SES-CHDs associations adjusted for confounders. Both low maternal income and education were significantly associated with increased risks of CHDs and lower prevalence of FAS. Low maternal FAS prevalence mediated 10% [95%CI:5%,13%] and 3% [95%CI:1%,5%] of the maternal low income-CHDs and the maternal low education-CHDs associations, respectively. In addition, FAS mediated the highest proportion of the associations between income and multiple critical CHDs [46.9%, 95%CI:24.7%,77%] and conotruncal defects [31.5%, 95%CI:17.1%,52.0%], respectively. Maternal FAS partially mediated the SES-CHDs associations, especially among the most critical and common CHDs. Promoting FAS in low SES women of childbearing age may be a feasible intervention to help prevent CHDs.

"Repair of common atrioventricular junction in isolation and when associated with other congenital heart defects"

Management of atrioventricular septal defects has grown leaps and bounds since the first correction of this malformation. Main reasons considered for the improvement are good understanding of lesion anatomy, precise preoperative diagnosis including imaging, progress in surgical technique, myocardial protection, and post-operative care. In this article we review the anatomy, pathophysiology, clinical features, associations, diagnosis, surgical therapy, complications, and results of atrioventricular septal defects.

Environmental and Socioeconomic Factors Influence the Live-Born Incidence of Congenital Heart Disease: A Population-Based Study in California

BACKGROUND

The development of congenital heart disease (CHD) is multifactorial with genetic and environmental influences. We sought to determine the relationship between socioeconomic and environmental factors with the incidence of CHD among live‐born infants in California and to determine whether maternal comorbidities are in the causal pathway.

METHODS AND RESULTS

This was a population‐based cohort study in California (2007–2012). The primary outcome was having significant CHD. Predictors included socioeconomic status and environmental exposure to pollutants determined by U.S. Census data. A social deprivation index and environmental exposure index was assigned based on neighborhood socioeconomic variables, categorized into 4 quartiles. Quartile 1 was the best with the least exposure to pollutants and social deprivation, and quartile 4 was the worst. Multivariate logistic regression and mediation analyses were performed. Among 2 419 651 live‐born infants, the incidence of CHD was 3.2 per 1000 live births. The incidence of CHD was significantly higher among those in quartile 4 compared with quartile 1 (social deprivation index: 0.35% versus 0.29%; odds ratio [OR], 1.31; 95% CI, 1.21–1.41; environmental exposure index: 0.35% versus 0.29%; OR, 1.23; 95% CI, 1.15–1.31) after adjusting for maternal race/ethnicity and age and accounting for the relationship between the 2 primary predictors. Maternal comorbidities explained 13% (95% CI, 10%–20%) of the relationship between social deprivation index and environmental exposure index with the incidence of CHD.

CONCLUSIONS

Increased social deprivation and exposure to environmental pollutants are associated with the incidence of live‐born CHD in California. Maternal comorbidities explain some, but not all, of this relationship. These findings identify targets for social policy initiatives to minimize health disparities.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Caracterización de la exposición prenatal de un grupo de niños de 0 a 5 años con cardiopatía congénita atendidos en Cali, Colombia. La importancia del ácido fólico

Introducción. Con una prevalencia estimada de 4 a 9 casos por cada 1 000 nacimientos, las cardiopatías congénitas (CC) tienen gran impacto en la morbimortalidad pediátrica. La variabilidad de prevalencia se ha atribuido a diferencias regionales en cuanto a factores genéticos, ambientales, entre otros.Objetivo. Obtener datos sobre variables de exposición prenatales de pacientes con CC atendidos en Cali, Colombia.Materiales y métodos. Se aplicó una encuesta a las madres de 30 pacientes de 0 a 5 años con CC atendidos en 2 clínicas de alta complejidad (tercer y cuarto nivel) de Cali. La encuesta estaba orientada a múltiples variables de exposición y la información recolectada fue digitalizada en una base de datos en el programa Microsoft Excel para hacer un análisis estadístico descriptivo.Resultados. Se evidenciaron varias exposiciones potencialmente asociadas a CC, tales como índice de masa corporal alterado, administración inadecuada de suplementos de ácido fólico y exposición a vitamina A, rayos X, alcohol y cigarrillo.Conclusión. El consumo insuficiente o inoportuno de ácido fólico podría facilitar la generación de efectos teratogénicos de sustancias oxidantes. Por lo tanto, se debe educar a las mujeres de Cali sobre la importancia de una ingesta adecuada de ácido fólico y sobre los riesgos de la exposición a agentes teratogénicos durante el embarazo para reducir las tasas de incidencia de CC en esta ciudad.

Effects of Fetal Exposure to Heat-Not-Burn Tobacco on Testicular Function in Male Offspring

Several studies show that maternal conventional cigarette smoking during pregnancy has been associated with reduced sperm concentration in sons. The development of heat-not-burn (HnB) tobacco has gained a growing following. However, the effects of prenatal HnB tobacco smoking on male offspring are as yet unknown. Pregnant CD-1 mice were exposed to I-Quit-Ordinary-Smoking (IQOS) (HnB tobacco) aerosol from heat sticks, mainstream smoke from 3R4F (conventional cigarettes) or clean air, using a whole-body exposure system. Adult male offspring mice were divided into six groups: control (5- and 15-weeks-old offspring), IQOS (5 and 15-weeks-old) and 3R4F (5 and 15-weeks-old). Spermatogenesis, sperm characteristics, serum testosterone, and seminiferous tubule morphology were evaluated. Prenatal IQOS exposure increased abnormal seminiferous tubule morphology and decreased sperm production at 5 weeks, but 3R4F exposure did not. Prenatal exposure to IQOS aerosol delays sexual maturation of male offspring or adversely affects the male testicular function of the offspring more than smoke from a combustion cigarette.

Some Isolated Cardiac Malformations Can Be Related to Laterality Defects

Human beings are characterized by a left–right asymmetric arrangement of their internal organs, and the heart is the first organ to break symmetry in the developing embryo. Aberrations in normal left–right axis determination during embryogenesis lead to a wide spectrum of abnormal internal laterality phenotypes, including situs inversus and heterotaxy. In more than 90% of instances, the latter condition is accompanied by complex and severe cardiovascular malformations. Atrioventricular canal defect and transposition of the great arteries—which are particularly frequent in the setting of heterotaxy—are commonly found in situs solitus with or without genetic syndromes. Here, we review current data on morphogenesis of the heart in human beings and animal models, familial recurrence, and upstream genetic pathways of left–right determination in order to highlight how some isolated congenital heart diseases, very common in heterotaxy, even in the setting of situs solitus, may actually be considered in the pathogenetic field of laterality defects.

A parent-of-origin analysis of paternal genetic variants and increased risk of conotruncal heart defects

The association between conotruncal heart defects (CTHDs) and maternal genetic and environmental exposures is well studied. However, little is known about paternal genetic or environmental exposures and risk of CTHDs. We assessed the effect of paternal genetic variants in the folate, homocysteine, and transsulfuration pathways on risk of CTHDs in offspring. We utilized National Birth Defects Prevention Study data to conduct a family-based case only study using 616 live-born infants with CTHDs, born October 1997-August 2008. Maternal, paternal and infant DNA was genotyped using an Illumina® Golden Gate custom single nucleotide polymorphism (SNP) panel. Relative risks (RR) and 95% confidence intervals (CI) from log-linear models determined parent of origin effects for 921 SNPs in 60 candidate genes involved in the folate, homocysteine, and transsulfuration pathways on risk of CTHDs. The risk of CTHD among children who inherited a paternally derived copy of the A allele on GLRX (rs17085159) or the T allele of GLRX (rs12109442) was 0.23 (95%CI: 0.12, 0.42; p = 1.09 × 10^-6 ) and 0.27 (95%CI: 0.14, 0.50; p = 2.06 × 10^-5 ) times the risk among children who inherited a maternal copy of the same allele. The paternally inherited copy of the GSR (rs7818511) A allele had a 0.31 (95%CI: 0.18, 0.53; p = 9.94 × 10^-6 ] risk of CTHD compared to children with the maternal copy of the same allele. The risk of CTHD is less influenced by variants in paternal genes involved in the folate, homocysteine, or transsulfuration pathways than variants in maternal genes in those pathways.

Maternal and infant genetic variants, maternal periconceptional use of selective serotonin reuptake inhibitors, and risk of congenital heart defects in offspring: population based study

Objective To evaluate whether the association between maternal periconceptional use of selective serotonin reuptake inhibitors (SSRIs) and increased risk of congenital heart defects in offspring is modified by maternal or infant genetic variants in folate, homocysteine, or transsulfuration pathways.Design Population based study. DNA from mothers, fathers, and infants was genotyped with an Illumina GoldenGate custom single nucleotide polymorphism panel. A hybrid design based on a log linear model was used to calculate relative risks and Bayesian false discovery probabilities (BFDP) to identify polymorphisms associated with congenital heart defects modified by SSRI use.Data sources Data from the US National Birth Defects Prevention Study on 1180 liveborn infants with congenital heart defects and 1644 controls, born 1997-2008.Main outcome measures Cases included infants with selected congenital heart defects and control infants had no major defects. SSRI use was obtained from telephone interviews with mothers.Results For women who reported taking SSRIs periconceptionally, maternal SHMT1 (rs9909104) GG and AGgenotypes were associated with a 5.9 and 2.4 increased risk of select congenital heart defects in offspring, respectively, versus the AA genotype (BFDP=0.69). Compared with the AA genotype, BHMT (rs492842 and rs542852) GG and AG genotypes were associated with twice the riskof congenital heart defects (BFDP=0.74 and 0.79, respectively). MGST1 (rs2075237) CC and ACgenotypes were associated with an increased risk compared with the GG genotype (8.0 and 2.8, respectively; BFDP=0.79). Single nucleotide polymorphism in infant genes in the folate (MTHFS rs12438477), homocysteine (TRDMT1 rs6602178 and GNMT rs11752813) and transsulfuration (GSTP1 rs7941395 and MGST1 rs7294985) pathways were also associated with an increased risk of congenital heart defects.Conclusions Common maternal or infant genetic variants in folate, homocysteine, or transsulfuration pathways are associated with an increased risk of certain congenital heart defects among children of women taking SSRIs during cardiogenesis.

Associations between maternal periconceptional exposure to secondhand tobacco smoke and major birth defects

BACKGROUND

While associations between secondhand smoke and a few birth defects (namely, oral clefts and neural tube defects) have been noted in the scientific literature, to our knowledge, there is no single or comprehensive source of population-based information on its associations with a range of birth defects among nonsmoking mothers.

OBJECTIVE

We utilized data from the National Birth Defects Prevention Study, a large population-based multisite case-control study, to examine associations between maternal reports of periconceptional exposure to secondhand smoke in the household or workplace/school and major birth defects.

STUDY DESIGN

The multisite National Birth Defects Prevention Study is the largest case-control study of birth defects to date in the United States. We selected cases from birth defect groups having >100 total cases, as well as all nonmalformed controls (10,200), from delivery years 1997 through 2009; 44 birth defects were examined. After excluding cases and controls from multiple births and whose mothers reported active smoking or pregestational diabetes, we analyzed data on periconceptional secondhand smoke exposure-encompassing the period 1 month prior to conception through the first trimester. For the birth defect craniosynostosis, we additionally examined the effect of exposure in the second and third trimesters as well due to the potential sensitivity to teratogens for this defect throughout pregnancy. Covariates included in all final models of birth defects with ≥5 exposed mothers were study site, previous live births, time between estimated date of delivery and interview date, maternal age at estimated date of delivery, race/ethnicity, education, body mass index, nativity, household income divided by number of people supported by this income, periconceptional alcohol consumption, and folic acid supplementation. For each birth defect examined, we used logistic regression analyses to estimate both crude and adjusted odds ratios and 95% confidence intervals for both isolated and total case groups for various sources of exposure (household only; workplace/school only; household and workplace/school; household or workplace/school).

RESULTS

The prevalence of secondhand smoke exposure only across all sources ranged from 12.9-27.8% for cases and 14.5-15.8% for controls. The adjusted odds ratios for any vs no secondhand smoke exposure in the household or workplace/school and isolated birth defects were significantly elevated for neural tube defects (anencephaly: adjusted odds ratio, 1.66; 95% confidence interval, 1.22-2.25; and spina bifida: adjusted odds ratio, 1.49; 95% confidence interval, 1.20-1.86); orofacial clefts (cleft lip without cleft palate: adjusted odds ratio, 1.41; 95% confidence interval, 1.10-1.81; cleft lip with or without cleft palate: adjusted odds ratio, 1.24; 95% confidence interval, 1.05-1.46; cleft palate alone: adjusted odds ratio, 1.31; 95% confidence interval, 1.06-1.63); bilateral renal agenesis (adjusted odds ratio, 1.99; 95% confidence interval, 1.05-3.75); amniotic band syndrome-limb body wall complex (adjusted odds ratio, 1.66; 95% confidence interval, 1.10-2.51); and atrial septal defects, secundum (adjusted odds ratio, 1.37; 95% confidence interval, 1.09-1.72). There were no significant inverse associations observed.

CONCLUSION

Additional studies replicating the findings are needed to better understand the moderate positive associations observed between periconceptional secondhand smoke and several birth defects in this analysis. Increased odds ratios resulting from chance (eg, multiple comparisons) or recall bias cannot be ruled out.

Mainstream smoke and sidestream smoke affect the cardiac differentiation of mouse embryonic stem cells discriminately

Epidemiology studies suggest that maternal smoking and passive smoking have strongly resulted in the occurrence of congenital heart defects (CHD) in offspring. Cigarette smoke (CS) can be divided into mainstream smoke (MS) and sidestream smoke (SS); CS chemistry study indicates that significant differences exist in the composition of MS and SS. Therefore, MS and SS were suspected to process toxicity dissimilarly. However, much less was known about the difference in the developmental effects induced by MS and SS. In the current study, heart development was mimicked by mouse embryonic stem cells (ESCs) differentiation. After MS and SS exposure, by tracing the bone morphogenetic protein (BMP)-Smad4 signalling pathway, interruption of downstream gene expression was observed, including Gata4, Mef2c and Nkx2.5, as well as myosin heavy chain and myosin light chain. Specifically, SS caused inhibition of Gata4 expression, even at non-cytotoxic concentration. Further, SS-induced hypoacetylation in promoter regions of Gata4 reflected the orchestration of CS-gene modulation-epigenetic regulation. Even though SS induced apoptosis in ESC-derived cardiomyocytes, the partial clearance in cells with down-regulated Gata4 caused these cells to survive and undergo further differentiation, which laid potential risk for abnormal heart development. These data uncovered the difference between MS and SS on heart development preliminarily.

Is maternal smoking during pregnancy associated with an increased risk of congenital heart defects among offspring? A systematic review and meta-analysis of observational studies

OBJECTIVE

To investigate the association between maternal smoking during pregnancy and risk of congenital heart defects (CHDs) among offspring.

METHODS

PubMed, EMBASE, and Web of Science were searched for eligible studies. The outcomes of interest included risk of any CHD and nine subtypes. We summarized study characteristics and used a random-effects model in meta-analysis, and a two-stage dose-response model was utilized to assess the association between smoking consumption and risk. Statistical heterogeneity was assessed by a chi-squared test of the Cochrane Q statistic and I-squared value. Publication bias was assessed by funnel plots and Egger's test, and trim and fill method was utilized when publication bias existed.

RESULTS

Forty-three observational epidemiologic studies were included. The pooled risk ratio (RR) of any CHD was 1.11 (95% CI: 1.04, 1.18), but it exhibited substantial statistical heterogeneity (p < 0.001, I²=69.0%). In sensitivity analysis, we observed significant associations for atrial septal defect (ASD) and marginally significant associations for septal defects (SPD). The two-stage dose-response analysis showed evidence to support that higher levels of tobacco smoke was associated with an increased risk of septal defects, particularly for ASD and VSD (ventricular septal defect).

CONCLUSION

Our study presents evidence to support the cardiovascular teratogenic effect of maternal smoking during pregnancy, and their offspring may suffer from approximately a 10% relative increase in the risk of CHDs on average.

Intrauterine Tobacco Smoke Exposure and Congenital Heart Defects

Tobacco use and second-hand smoke exposure during pregnancy are linked to a host of deleterious effects on the pregnancy, fetus, and infant. Health outcomes improve when women quit smoking at any time during the pregnancy. However, the developing heart is vulnerable to noxious stimuli in the early weeks of fetal development, a time when many women are not aware of being pregnant. Congenital heart defects are the most common birth defects. Research shows an association between maternal tobacco exposure, both active and passive, and congenital heart defects. This article presents recent evidence supporting the association between intrauterine cigarette smoke exposure in the periconceptional period and congenital heart defects and discusses clinical implications for practice for perinatal and neonatal nurses.

Hypoplastic left heart syndrome is associated with structural and vascular placental abnormalities and leptin dysregulation

INTRODUCTION

Hypoplastic left heart syndrome (HLHS) is a severe cardiovascular malformation (CVM) associated with fetal growth abnormalities. Genetic and environmental factors have been identified that contribute to pathogenesis, but the role of the placenta is unknown. The purpose of this study was to systematically examine the placenta in HLHS with and without growth abnormalities.

METHODS

HLHS term singleton births were identified from a larger cohort when placenta tissue was available. Clinical data were collected from maternal and neonatal medical records, including anthropometrics and placental pathology reports. Placental tissues from cases and controls were analyzed to assess parenchymal morphology, vascular architecture and leptin signaling.

RESULTS

HLHS cases (n = 16) and gestational age-matched controls (n = 18) were analyzed. Among cases, the average birth weight was 2993 g, including 31% that were small for gestational age. When compared with controls, gross pathology of HLHS cases demonstrated significantly reduced placental weight and increased fibrin deposition, while micropathology showed increased syncytial nuclear aggregates, decreased terminal villi, reduced vasculature and increased leptin expression in syncytiotrophoblast and endothelial cells.

DISCUSSION

Placentas from pregnancies complicated by fetal HLHS are characterized by abnormal parenchymal morphology, suggesting immature structure may be due to vascular abnormalities. Increased leptin expression may indicate an attempt to compensate for these vascular abnormalities. Further investigation into the regulation of angiogenesis in the fetus and placenta may elucidate the causes of HLHS and associated growth abnormalities in some cases.

Association of TGFBR2 rs6785358 Polymorphism with Increased Risk of Congenital Ventricular Septal Defect in a Chinese Population

Transforming growth factor beta receptor 2 (TGFBR2) plays a central role in normal heart development, and we investigated whether TGFBR2 polymorphism confers the risk of congenital ventricular septal defect (CVSD). The case-control study included 115 CVSD children and 188 healthy children in a Chinese population. TGFBR2 rs6785358 polymorphism was genotyped with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Enzyme-linked immunoassay (ELISA) was used to detect serum TGFBR2 levels. The genotype and allele frequency of TGFBR2 rs6785358 were significantly higher in the CVSD group than in the controls (all P < 0.05). The G allele carriers were associated with increased CVSD risk compared with the A allele carriers in CVSD group (OR 3.503, 95 % CI 2.670-4.596). Stratified analysis by gender revealed that the TGFBR2 rs6785358 genotype and allele frequency were significantly different between the CVSD case and controls, in both the male subgroup and the female subgroup (all P < 0.001). The G allele carriers were more susceptible to CVSD risk than the A allele carriers in both the male subgroup (OR 9.096, 95 % CI 5.398-15.33) and the female subgroup (OR 3.148, 95 % CI 1.764-5.618). Logistic regression analysis revealed that age, gender and genotype were associated with the risk of CVSD (all P < 0.05). The study findings revealed that TGFBR2 rs6785358 polymorphism contributes to CVSD susceptibility, and the G allele may increase the risk of CVSD.

Prenatal Alcohol Exposure and Congenital Heart Defects: A Meta-Analysis

Background

There are still inconsistent conclusions about the association of prenatal alcohol drinking with congenital heart defects (CHDs). We conducted this meta-analysis to investigate the association between prenatal alcohol exposure and the risk of overall CHDs and the CHDs subtypes.

Methods

Case-control and cohort studies published before March 2015 were searched through PubMed and Embase. Two authors independently extracted data and scored the study quality according to the Newcastle-0ttawa Scale. The pooled ORs and 95%CI were estimated using the random-effects model and heterogeneity was assessed by the Q test and I² statistic.

Results

A total of 20 studies were finally included. The results provided no evidence of the association between prenatal alcohol exposure and the risk of overall CHDs (OR = 1.06, 95%CI = 0.93–1.22), ventricular septal defects (VSDs) (OR = 1.04, 95%CI = 0.86–1.25), or atrial septal defects (ASDs) (OR = 1.40, 95%CI = 0.88–2.23). However, prenatal alcohol drinking was marginally significantly associated with conotruncal defects (CTDs) (OR = 1.24, 95%CI = 0.97–1.59) and statistically significantly associated with d-Transposition of the Great Arteries (dTGA) (OR = 1.64, 95%CI = 1.17–2.30). Moreover, both prenatal heavy drinking and binge drinking have a strong association with overall CHDs (heavy drinking: OR = 3.76, 95%CI = 1.00–14.10; binge drinking: OR = 2.49, 95%CI = 1.04–5.97), and prenatal moderate drinking has a modest association with CTDs (OR = 1.35, 95%CI = 1.05–1.75) and dTGA (OR = 1.86, 95%CI = 1.09–3.20).

Conclusions

In conclusion, the results suggested that prenatal alcohol exposure was not associated with overall CHDs or some subtypes, whereas marginally significant association was found for CTDs and statistically significant association was found for dTGA. Further prospective studies with large population and better designs are needed to explore the association of prenatal alcohol exposure with CHDs including the subtypes in specific groups.

Genetic variation affects congenital heart defect susceptibility in offspring exposed to maternal tobacco use

BACKGROUND

Congenital heart defects (CHDs) are among the most prevalent and serious birth defects, occurring in 8 to 10 of every 1000 live births in the United States. Epidemiologic studies have reported an association between CHDs and maternal smoking, but it remains unknown how genes impact the susceptibility of offspring to CHDs in the presence of maternal tobacco use.

METHODS

Using data from 403 case- and 219 control-parental triads enrolled in the National Birth Defects Prevention Study between 1998 and 2008, we investigated the association between CHDs and maternal and infant genetic variants involved in the tobacco metabolism and DNA repair pathways among mothers who smoked prenatally.

RESULTS

The maternal genotypes of single nucleotide polymorphisms in the excision repair cross-complementation group 1 (ERCC1), poly (ADP-ribose) polymerase 2 (PARP2), and ERCC5 genes were identified to be significantly associated with the occurrence of CHDs in the presence of maternal tobacco use. Our analysis also revealed a moderate association between the infant genotypes of polymorphisms in the O-sialoglycoprotein endopeptidase (OSGEP) gene and increased risk of CHDs among mothers who smoked.

CONCLUSION

Our study provides evidence that maternal and infant polymorphisms within the ERCC1, PARP2, ERCC5, and OSGEP genes are associated with CHD risk in the presence of maternal tobacco use. These results may provide insight into the susceptibility of having a pregnancy affected by CHDs among women who smoke.

A spectrum project: preterm birth and small-for-gestational age among infants with birth defects

OBJECTIVE

The aim of this study is to investigate the association between birth defects (BDs), prematurity and small-for-gestational age (SGA) in a population-based sample.

STUDY DESIGN

Participants were singleton live births enrolled in the National Birth Defects Prevention Study, including 18 737 case infants with one or more BD and 7999 controls. Logistic regression models to evaluate associations between BDs, prematurity and fetal growth were computed while adjusting for covariates.

RESULT

Cases were significantly more likely to be born prematurely than controls, particularly at 24 to 28 weeks of gestation. The highest odds ratios for preterm birth were found for intestinal atresia, anencephaly, gastroschisis and esophageal atresia. Infants with BDs were also significantly more likely to be SGA than controls (17.2 and 7.8%).

CONCLUSION

Infants with BDs are more likely than controls to be born prematurely and SGA. Findings from this study present additional evidence demonstrating a complex interaction between the development of BDs, prematurity and intrauterine growth.

Maternal lifestyle factors in pregnancy and congenital heart defects in offspring: review of the current evidence

The prognosis of children with congenital heart defects(CHDs) continues to improve with advancing surgical techniques; however, lack of information about modifiable risk factors for malformations in cardiovascular development impeded the prevention of CHDs. We investigated an association between maternal lifestyle factors and the risk of CHDs, because epidemiological studies have reported conflicting results regarding maternal lifestyle factors and the risk of CHDs recently. A review published on 2007 provided a summary of maternal exposures associated with an increased risk of CHDs. As part of noninherited risk factors, we conducted a brief overview of studies on the evidence linking common maternal lifestyle factors, specifically smoking, alcohol, illicit drugs, caffeine, body mass index and psychological factors to the development of CHDs in offspring. Women who smoke and have an excessive body mass index(BMI) during pregnancy are suspected to be associated with CHDs in offspring. Our findings could cause public health policy makers to pay more attention to women at risk and could be used in the development of population-based prevention strategies to reduce the incidence and burden of CHDs. However, more prospective studies are needed to investigate the association between maternal lifestyle factors and CHDs.

Maternal socioeconomic status and the risk of congenital heart defects in offspring: a meta-analysis of 33 studies

Background

We conducted this meta-analysis to address the open question of a possible association between maternal socioeconomic status and congenital heart defects (CHDs).

Methods

We searched MEDLINE and EMBASE from their inception to January 1, 2014 for case-control and cohort studies that assessed the association between maternal socioeconomic status and the risk of CHDs. Study-specific relative risk estimates were polled according to random-effect or fixed-effect models.

Results

From 3343 references, a total of 31 case-control studies and 2 cohort studies were enrolled in this meta-analysis, including more than 50,000 cases. We observed that maternal educational attainment, family income and maternal occupation were negatively associated with an 11% (pooled RR = 1.11, 95% CI: 1.03, 1.21), 5% (pooled RR = 1.05, 95% CI: 1.01, 1.09) and 51% (pooled RR = 1.51, 95% CI: 1.02, 2.24) increased risk of CHDs, respectively. In a subgroup analysis by geographic region, the results were inconsistent for the European region (RR = 1.29, 95% CI: 0.99–1.69) and USA/Canada region (RR = 1.06, 95% CI: 0.97, 1.16) in maternal educational attainment.

Conclusion

In summary, this meta-analysis suggests that a lower degree of maternal socioeconomic status is modestly associated with an increased risk of CHDs. However, further investigations are needed to confirm the association.

Early births and congenital birth defects: a complex interaction

Congenital birth defects and early/premature birth are common complex conditions affecting populations throughout the world, the interaction of which accounts for a significant proportion of neonatal morbidity and mortality. The relationship between these two conditions is not well understood. Several congenital birth defects can directly lead to early delivery. In addition, certain fetal conditions may necessitate early or premature delivery, several of which are also associated with maternal conditions necessitating early birth. Further understanding of both the incidences and causes of congenital birth defects and of early and premature birth will facilitate establishment of strategies to improve neonatal mortality and morbidity.

Nongenetic risk factors and congenital heart defects

Advances have been made in identifying genetic etiologies of congenital heart defects. Through this knowledge, preventive strategies have been designed and instituted, and prospective parents are counseled regarding their risk of having an affected child. Great strides have been made in genetic variant identification, and genetic susceptibility to environmental exposures has been hypothesized as an etiology for congenital heart defects. Unfortunately, similar advances in understanding have not been made regarding strategies to prevent nongenetic risk factors. Less information is available regarding the potential adverse effect of modifiable risk factors on the fetal heart. This review summarizes the available literature on these modifiable exposures that may alter the risk for congenital heart disease. Information regarding paternal characteristics and conditions, maternal therapeutic drug exposures, parental nontherapeutic drug exposures, and parental environmental exposures are presented. Factors are presented in terms of risk for congenital heart defects as a group. These factors also are broken down by specific defect type. Although additional investigations are needed in this area, many of the discussed risk factors present an opportunity for prevention of potential disease.