Association between maternal chronic conditions and congenital heart defects: a population-based cohort study

Maternal hypothyroidism may be associated with CHD in offspring

OBJECTIVES

This study tested whether mothers with maternal hypothyroidism have increased odds of CHD in their offspring, and examined the relationship between CHD, maternal thyroid function, and nausea and vomiting in pregnancy.

BACKGROUND

Maternal hypothyroidism increases the risk for foetal demise and prematurity and can have a negative impact on neurodevelopment. Prior studies have postulated a relationship between maternal thyroid function, CHD, and maternal nausea and vomiting in pregnancy.

METHODS

A cross-sectional case-control study was conducted over a 17-month period to obtain a history of maternal thyroid status and nausea and vomiting in pregnancy. Paediatric echocardiograms were evaluated for CHD by a blinded paediatric cardiologist. Logistic regression analysis was performed to examine the association between CHD and maternal hypothyroidism.

RESULTS

Of the 998 maternal-child pairs, 10% (98/998) of the mothers reported a history of prenatal hypothyroidism. The overall prevalence of CHD in the study sample was 63% (630/998). Mothers with a history of hypothyroidism were significantly more likely to have offspring with CHD compared with mothers without a history of hypothyroidism (72 versus 62%; p=0.04). The adjusted odds ratio (95% confidence interval) of CHD in offspring associated with reported maternal hypothyroidism was 1.68 (1.02-2.78).

CONCLUSION

This study suggests that maternal hypothyroidism is a risk factor for the development of CHD. Further prospective investigations are necessary to confirm this association and delineate pathogenic mechanisms.

Maternal Hypertension During Pregnancy and the Risk of Congenital Heart Defects in Offspring: A Systematic Review and Meta-analysis

Maternal hypertension is common during pregnancy, and multiple studies have reported on an association between maternal hypertension and congenital heart defects (CHDs) in offspring; however, there is variability in the quality of these studies. A systematic review and meta-analysis was conducted on the associations between untreated and treated maternal hypertension and the risk of CHDs, evaluating CHDs overall as well as specific CHD subtypes. A systematic search of peer-reviewed articles published before August 2013 identified 16 studies evaluating the associations between untreated and treated maternal hypertension and CHDs. Summary relative risk (RR) estimates were calculated using fixed-effects models and random-effects models. Significant associations were observed between maternal hypertension and overall CHDs, for both treated [RR 2.0; 95 % confidence interval (CI) 1.5, 2.7] and untreated (RR 1.4; 95 % CI 1.2, 1.7) hypertension, as well as for overall hypertension regardless of treatment status (RR 1.8; 95 % CI 1.5, 2.2). The magnitude of effect was similar for the majority of CHD subtypes evaluated. The effects were also similar among women with hypertension who used one of multiple specific hypertension medications. There was no evidence of publication bias, and our results were robust to several factors considered in sensitivity analyses (e.g., source of exposure data, adjustment for potential confounders, and study design). Maternal hypertension was associated with CHDs. By understanding the specific mechanisms involved, appropriate strategies may be developed to reduce this risk, in order to prevent CHDs.

Hyperglycemia impairs left-right axis formation and thereby disturbs heart morphogenesis in mouse embryos

Congenital heart defects with heterotaxia are associated with pregestational diabetes mellitus. To provide insight into the mechanisms underlying such diabetes-related heart defects, we examined the effects of high-glucose concentrations on formation of the left-right axis in mouse embryos. Expression of Pitx2, which plays a key role in left-right asymmetric morphogenesis and cardiac development, was lost in the left lateral plate mesoderm of embryos of diabetic dams. Embryos exposed to high-glucose concentrations in culture also failed to express Nodal and Pitx2 in the left lateral plate mesoderm. The distribution of phosphorylated Smad2 revealed that Nodal activity in the node was attenuated, accounting for the failure of left-right axis formation. Consistent with this notion, Notch signal-dependent expression of Nodal-related genes in the node was also down-regulated in association with a reduced level of Notch signaling, suggesting that high-glucose concentrations impede Notch signaling and thereby hinder establishment of the left-right axis required for heart morphogenesis.

A case report of aorto-pulmonary window in an infant born to a diabetic mother

Several studies have described the association between pre-gestational maternal diabetes and cardiac disease in the newborn. Infants of diabetic mothers have an increased incidence of congenital heart disease, reported between 3% and 6% compared to 0.8% of the general population. A particularly high prevalence of conotruncal defects has been recently described among congenital heart diseases. This group of malformations affects ventricular outflows, aorta, and pulmonary artery and shares a common embryogenic origin. They include persistence of the truncus arteriosus, transposition of great arteries, tetralogy of Fallot, interruption of the aortic arch, and double outlet right ventricle. Aorto-pulmonary window, a rare congenital heart disease belonging to conotruncal malformations, has never been previously described in association with maternal diabetes. We describe the case of a male infant born to a mother suffering from a poorly controlled type 1 diabetes during pregnancy. In the early postnatal life the infant showed respiratory distress, tachycardia, and failure to thrive. He was found to be affected by aorto-pulmonary window that required corrective surgical intervention. <Learning objective: This case report warns us to consider this congenital abnormality as a possible finding in infants born to a diabetic mother. Furthermore, it shows how difficult the echocardiographic diagnosis of aorto-pulmonary windows can be.>.

Impact of pre-pregnancy diabetes mellitus on congenital anomalies, Canada, 2002-2012

OBJECTIVE

To examine the impact of pre-pregnancy diabetes mellitus (DM) on the population birth prevalence of congenital anomalies in Canada.

METHODS

We carried out a population-based study of all women who delivered in Canadian hospitals (except those in the province of Quebec) between April 2002 and March 2013 and their live-born infants with a birth weight of 500 grams or more and/or a gestational age of 22 weeks or more. Pre-pregnancy type 1 or type 2 DM was identified using ICD-10 diagnostic codes. The association between DM and all congenital anomalies as well as specific congenital anomaly categories was estimated using adjusted odds ratios; the impact was calculated as a population attributable risk percent (PAR%).

RESULTS

There were 118,892 infants with a congenital anomaly among 2,839,680 live births (41.9 per 1000). While the prevalence of any congenital anomaly declined from 50.7 per 1000 live births in 2002/03 to 41.5 per 1000 in 2012/13, the corresponding PAR% for a congenital anomaly related to pre-pregnancy DM rose from 0.6% (95% confidence interval [CI]: 0.4-0.8) to 1.2% (95% CI: 0.9-1.4). Specifically, the PAR% for congenital cardiovascular defects increased from 2.3% (95% CI: 1.7-2.9) to 4.2% (95% CI: 3.5-4.9) and for gastrointestinal defects from 0.8% (95% CI: 0.2-1.9) to 1.4% (95% CI: 0.7-2.6) over the study period.

CONCLUSION

Although there has been a relative decline in the prevalence of congenital anomalies in Canada, the proportion of congenital anomalies due to maternal pre-pregnancy DM has increased. Enhancement of preconception care initiatives for women with DM is recommended.

Maternal Alcohol Consumption before and during Pregnancy and the Risks of Congenital Heart Defects in Offspring: A Systematic Review and Meta-analysis

OBJECTIVE

Epidemiologic studies have reported conflicting results regarding maternal alcohol consumption before and during pregnancy, and the risk of congenital heart defects (CHDs). However, a systematic review and meta-analysis of the association between maternal alcohol consumption and CHDs in offspring has not been conducted.

DESIGN

We searched MEDLINE and EMBASE for articles catalogued between their inception and February 16, 2015; we identified relevant published studies that assessed the association between maternal alcohol consumption and CHD risk. Two authors independently assessed the eligibility of the retrieved articles and extracted data from them. Study-specific relative risk estimates were pooled by random-effects or fixed-effects models.

RESULTS

From the 1527 references, a total of 19 case-control studies and four cohort studies were enrolled in this meta-analysis. The summary of 23 studies related to CHDs indicated an overall pooled relative risk of 1.13 (95% confidence interval: 0.96, 1.29) among mothers drinking before or during pregnancy. Statistically significant heterogeneity was detected (Q = 196.61, P < .001, I(2) = 88.8%) with no publication bias (Egger's test: P = .157). We conducted stratified and meta-regression analyses to identify the origin of the heterogeneity among studies.

CONCLUSION

In summary, this meta-analysis provided no positive association between maternal alcohol consumption and risk of CHDs.

Congenital anomalies in offspring of subfertile couples: a registry-based study in the northern Netherlands

OBJECTIVE

To study whether specific congenital anomalies occur more often with a history of subfertility and/or the use of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

DESIGN

Case-only analyses.

SETTING

Not applicable.

PATIENT(S)

We included live births, stillbirths, and terminated pregnancies with congenital anomalies without a known cause that had a birth year between 1997 and 2010 (n = 4,525). A total of 4,185 malformed cases were born to fertile couples and 340 to subfertile couples, of whom 139 had conceived after IVF/ICSI and 201 had conceived naturally after >12 months.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The contribution, expressed in odds ratios (ORs), of a history of subfertility and IVF/ICSI to each specific type of congenital anomaly, imprinting disorder, and syndromal disorder.

RESULT(S)

We found subfertility to be associated with an increase in abdominal wall defects (adjusted OR [aOR] 2.43, 95% CI 1.05-5.62), penoscrotal hypospadia (aOR 9.83, 95% CI 3.58-27.04), right ventricular outflow tract obstruction (aOR 1.77, 95% CI 1.06-2.97), and methylation defects causing imprinting disorders (aOR 13.49, 95% CI 2.93-62.06). In vitro fertilization/ICSI was associated with an increased risk of polydactyly (OR 4.83, 95% CI 1.39-16.77) and more specifically polydactyly of the hands (OR 5.02, 95% CI 1.43-17.65).

CONCLUSION(S)

In our registry-based study, parental subfertility was associated with an increase in abdominal wall defects, penoscrotal hypospadia, right ventricular outflow tract obstruction, and methylation defects causing imprinting disorders. In vitro fertilization/ICSI was associated with an increase in polydactyly, mainly of the hands.

Birth prevalence of congenital heart defects in Norway 1994-2009--a nationwide study

BACKGROUND

The reasons for decreasing birth prevalence of congenital heart defects (CHDs) in several European countries and Canada are not fully understood. We present CHD prevalence among live births, stillbirths, and terminated pregnancies in an entire nation over a period of 16 years.

METHODS

Information on all births in the Medical Birth Registry of Norway, 1994-2009, was updated with information on CHD from the hospitals' Patient Administrative Systems, the National Hospital's clinical database for children with heart disease, and the Cause of Death Registry. Individuals with heart defects were assigned specific cardiac phenotypes.

RESULTS

Among 954,413 births, 13,081 received a diagnosis of CHD (137.1 per 10,000 births, 133.2 per 10,000 live births). The prevalence per 10,000 births was as follows: heterotaxia, 1.6; conotruncal defects, 11.6; atrioventricular septal defects, 5.6; anomalous pulmonary venous return, 1.1; left outflow obstructions, 8.7; right outflow obstructions, 5.6; septal defects, 65.5; isolated patent ductus arteriosus, 24.6; and other specified or unspecified CHD, 12.7. Excluding preterm patent ductus arteriosus, the CHD prevalence was 123.4 per 10,000; per year, the prevalence increased with 3.5% (95% CI 2.5-4.4) in 1994-2005 and declined with 9.8% (-16.7 to -2.4) from 2005 onwards. Severe CHD prevalence was 30.7 per 10,000; per-year increase was 2.3% (1.1-3.5) in 1994-2004, and per-year decrease was 3.4% (-6.6 to -0.0) in 2004-2009. Numbers included severe CHD in stillbirths and terminated pregnancies.

CONCLUSIONS

The birth prevalence of CHD declined from around 2005. Specifically, the prevalence of severe CHD was reduced by 3.4% per year from 2004 through 2009.

Morphogenesis and molecular considerations on congenital cardiac septal defects

The primary unseptated heart tube undergoes extensive remodeling including septation at the atrial, atrioventricular, ventricular, and ventriculo-arterial level. Alignment and fusion of the septal components is required to ensure full septation of the heart. Deficiencies lead to septal defects at various levels. Addition of myocardium and mesenchymal tissues from the second heart field (SHF) to the primary heart tube, as well as a population of neural crest cells, provides the necessary cellular players. Surprisingly, the study of the molecular background of these defects does not show a great diversity of responsible transcription factors and downstream gene pathways. Epigenetic modulation and mutations high up in several transcription factor pathways (e.g. NODAL and GATA4) may lead to defects at all levels. Disturbance of modulating pathways, involving primarily the SHF-derived cell populations and the genes expressed therein, results at the arterial pole (e.g. TBX1) in a spectrum of ventricular septal defects located at the level of the outflow tract. At the venous pole (e.g. TBX5), it can explain a variety of atrial septal defects. The various defects can occur as isolated anomalies or within families. In this review developmental, morphological, genetic, as well as epigenetic aspects of septal defects are discussed.

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.

Increased congenital heart defects in children born to women with systemic lupus erythematosus: results from the offspring of Systemic Lupus Erythematosus Mothers Registry Study

BACKGROUND

In a large population-based study, we aimed to determine whether children born to women with systemic lupus erythematosus (SLE) have an increased risk of congenital heart defects (CHDs) in comparison with children born to women without SLE.

METHODS AND RESULTS

The Offspring of SLE Mothers Registry (OSLER) includes all women who had ≥1 hospitalization for delivery after SLE diagnosis, identified through Quebec's healthcare databases (1989-2009), and a randomly selected control group of women, matched ≥4:1 for age and year of delivery. We identified children born live to SLE mothers and their matched controls, and ascertained CHD based on ≥1 hospitalization or physician visit with relevant diagnostic codes, within the first 12 months of life. We performed multivariable logistic regression analyses, using the generalized estimating equation method, to adjust for relevant covariates. Five hundred nine women with SLE had 719 children, whereas 5824 matched controls had 8493 children. In comparison with controls, children born to women with SLE experienced more CHD (5.2% [95% confidence interval (CI), 3.7-7.1] versus 1.9% [95% CI, 1.6-2.2], difference 3.3% [95% CI, 1.9-5.2]). In multivariable analyses, children born to women with SLE had a substantially increased risk of CHD (odds ratio, 2.62; 95% CI, 1.77-3.88) in comparison with controls. In addition, in comparison with controls, offspring of SLE mothers had a substantially increased risk of having a CHD repair procedure (odds ratio, 5.82; 95% CI, 1.77-19.09).

CONCLUSIONS

In comparison with children from the general population, children born to women with SLE have an increased risk of CHD, and an increased risk of having a CHD repair procedure, as well.

Maternal parity and the risk of congenital heart defects in offspring: a dose-response meta-analysis of epidemiological observational studies

Background

Epidemiological studies have reported conflicting results regarding maternal parity and the risk of congenital heart defects (CHDs). However, a meta-analysis of the association between maternal parity and CHDs in offspring has not been conducted.

Methods

We searched MEDLINE and EMBASE for articles catalogued between their inception and March 8, 2014; we identified relevant published studies that assessed the association between maternal parity and CHD risk. Two authors independently assessed the eligibility of the retrieved articles and extracted data from them. Study-specific relative risk estimates were pooled by random-effects or fixed-effects models. From the 11272 references, a total of 16 case-control studies and 3 cohort studies were enrolled in this meta-analysis.

Results

The overall relative risk of CHD in parous versus nulliparous women was 1.01 (95% CI, 0.97–1.06; Q = 32.34; P = 0.006; I² = 53.6%). Furthermore, we observed a significant association between the highest versus lowest parity number, with an overall RR = 1.20 (95% CI, 1.10–1.31; (Q = 74.61, P<0.001, I² = 82.6%). A dose–response analysis also indicated a positive effect of maternal parity on CHD risk, and the overall increase in relative risk per one live birth was 1.06 (95% CI, 1.02–1.09); Q = 68.09; P<0.001; I² = 80.9%). We conducted stratified and meta-regression analyses to identify the origin of the heterogeneity among studies. A Galbraith plot was created to graphically assess the sources of heterogeneity.

Conclusion

In summary, this meta-analysis provided a robust estimate of the positive association between maternal parity and risk of CHD.

Risk of congenital malformations for asthmatic pregnant women using a long-acting β₂-agonist and inhaled corticosteroid combination versus higher-dose inhaled corticosteroid monotherapy

BACKGROUND

Current recommendations for managing persistent asthma during pregnancy when low-dose inhaled corticosteroids (ICSs) are insufficient include adding a long-acting β₂-agonist (LABA) or increasing the ICS dose. However, there are no data to help clinicians evaluate the safest regimen during pregnancy.

OBJECTIVE

We sought to compare the risk of major congenital malformations in asthmatic women exposed to a LABA plus ICS combination and those exposed to ICS monotherapy at higher doses during the first trimester.

METHODS

A cohort of asthmatic pregnant women exposed to ICSs during the first trimester who delivered between January 1990 and March 2009 was established. The primary outcome was major malformation recorded at birth or during the first year of life. Two subcohorts were established as follows: (1) users of a LABA plus low-dose ICS combination or users of a medium-dose ICS and (2) users of a LABA plus medium-dose ICS combination or users of a high-dose ICS. Generalized estimating equations were used to compare the risk of major malformations between the groups.

RESULTS

In one subcohort there were 643 women who used a LABA plus low-dose ICS and 305 who used a medium-dose ICS; the other subcohort included 198 users of a LABA plus medium-dose ICS and 156 users of a high-dose ICS. The prevalence of major malformations was 6.9% and 7.2%, respectively. The adjusted odds ratio for major malformations was 1.1 (95% CI, 0.6-1.9) when a LABA plus low-dose ICS was used compared with a medium-dose ICS and 1.2 (95% CI, 0.5-2.7) when a LABA plus medium-dose ICS was used compared with a high-dose ICS.

CONCLUSION

The risk of major malformations was similar with a LABA plus ICS combination and ICS monotherapy at higher doses, suggesting that both therapeutic options can be considered during pregnancy.

Receipt of prescription contraception by commercially insured women with chronic medical conditions

OBJECTIVE

To assess differences in receipt of prescription contraception among women with and without chronic medical conditions.

METHODS

This observational study used 3 years of administrative claims records for insured women aged 21-45 years who were enrolled in a commercial insurance company in Michigan between 2004 and 2009. Women were considered to have a chronic medical condition if they had at least two claims for one of the following conditions, in order of prevalence in our study population: hypertension, asthma, hypothyroidism, diabetes, obesity, rheumatoid arthritis, inflammatory bowel disease, or systemic lupus erythematosus. Our primary outcome was receipt of prescription contraception, defined by a pharmacy claim or diagnostic or procedural code. We used multivariable logistic regression to estimate the association of chronic condition status with the odds of receiving prescription contraception within 3 years adjusting for age, community-level socioeconomic status, total outpatient visits, and cervical cancer screening.

RESULTS

Of 11,649 women studied, 16.0% (n=1,862) had at least one of the chronic conditions we considered. Of those with a chronic condition, 33.5% (n=623) received prescription contraception during the 3-year study period compared with 41.1% (n=4,018) of those without a chronic condition (P<.001). After adjusting for covariates, women with a chronic condition remained less likely than women without a chronic condition to have received prescription contraception (adjusted odds ratio 0.85, 95% confidence interval 0.76-0.96, P=.010).

CONCLUSION

Despite a greater risk for adverse outcomes with an unplanned pregnancy, women with these chronic conditions were less likely to receive prescription contraception.

LEVEL OF EVIDENCE

III.

Risk of birth defects associated with maternal pregestational diabetes

Maternal diabetes preceding pregnancy may increase the risk of birth defects in the offspring, but not all studies confirm this association, which has shown considerable variation over time, and the effect of having type 1 versus type 2 diabetes is unclear. We conducted a population-based cohort study in the Northern Italy Emilia-Romagna region linking administrative databases with a Birth Defects Registry. From hospital discharge records we identified all diabetic pregnancies during 1997-2010, and a population of non-diabetic parturients matched for age, residence, year and delivery hospital. We collected available information on education, smoking and drug prescriptions, from which we inferred the type of diabetes. We found 62 malformed infants out of 2,269 births among diabetic women, and 162 out of 10,648 births among non-diabetic women. The age-standardized prevalence ratio (PR) of malformation associated with maternal pregestational diabetes was 1.79 (95 % confidence interval 1.34-2.39), a value that varied little by age. Type of diabetes strongly influenced the PR, with higher values related to type 2 diabetic women. Most major subgroups of anomalies had PRs above 1, including cardiovascular, genitourinary, musculoskeletal, and chromosomal abnormalities. There was an unusually high PR for the rare defect 'extra-ribs', but it was based on only two cases. This study indicates that maternal pregestational type 2 diabetes is associated with a higher prevalence of specific birth defects in offspring, whereas for type 1 diabetic mothers, particularly in recent years, the association was unremarkable.

N-Acetylcysteine prevents congenital heart defects induced by pregestational diabetes

BACKGROUND

Pregestational diabetes is a major risk factor of congenital heart defects (CHDs). Glutathione is depleted and reactive oxygen species (ROS) production is elevated in diabetes. In the present study, we aimed to examine whether treatment with N-acetylcysteine (NAC), which increases glutathione synthesis and inhibits ROS production, prevents CHDs induced by pregestational diabetes.

METHODS

Female mice were treated with streptozotocin (STZ) to induce pregestational diabetes prior to breeding with normal males to produce offspring. Some diabetic mice were treated with N-acetylcysteine (NAC) in drinking water from E0.5 to the end of gestation or harvesting of the embryos. CHDs were identified by histology. ROS levels, cell proliferation and gene expression in the fetal heart were analyzed.

RESULTS

Our data show that pregestational diabetes resulted in CHDs in 58% of the offspring, including ventricular septal defect (VSD), atrial septal defect (ASD), atrioventricular septal defects (AVSD), transposition of great arteries (TGA), double outlet right ventricle (DORV) and tetralogy of Fallot (TOF). Treatment with NAC in drinking water in pregestational diabetic mice completely eliminated the incidence of AVSD, TGA, TOF and significantly diminished the incidence of ASD and VSD. Furthermore, pregestational diabetes increased ROS, impaired cell proliferation, and altered Gata4, Gata5 and Vegf-a expression in the fetal heart of diabetic offspring, which were all prevented by NAC treatment.

CONCLUSIONS

Treatment with NAC increases GSH levels, decreases ROS levels in the fetal heart and prevents the development of CHDs in the offspring of pregestational diabetes. Our study suggests that NAC may have therapeutic potential in the prevention of CHDs induced by pregestational diabetes.