Birth outcomes of cases with left-sided obstructive defects of the heartin the function of maternal socio-demographic factors: a population-based case-control study

Maternal reproductive history and the risk of congenital heart defects in offspring: a systematic review and meta-analysis

Epidemiological studies have reported conflicting results on the association of congenital heart defect (CHD) risk in offspring with a maternal history of prior pregnancies and abortions, but no meta-analysis has been reported. We searched MEDLINE and EMBASE from their inception to April 14, 2014, for relevant studies that assessed the association between maternal reproductive history and CHD risk. Two authors independently assessed eligibility and extracted data. Fixed-effects or random-effects models were used to calculate the pooled odds ratios (ORs). Among 1,599 references, 17 case-control studies and one nested case-control study were included in this meta-analysis. The summary OR for the ever versus nulligravidity was 1.18 (95% CI 1.03-1.34). A dose-response analysis also indicated a positive effect of maternal gravidity on CHD risk, and the summary OR for each increment in number of pregnancies was 1.13 (95% CI 1.08-1.18). A history of abortion was associated with a 24% higher risk of CHD, OR = 1.24 (95% CI 1.11-1.38). When stratified by abortion category, CHD risk increased by 18 and 58% with a history of spontaneous abortion and induced abortion, respectively. The summary OR for each increment of one abortion was 1.28 (95% CI 1.18-1.40). In summary, this study provides evidence that increased maternal gravidity was positively associated with a risk of CHDs in offspring. Meanwhile, our results demonstrate a positive association of any history of abortion with an increased risk of 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.

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 factors in the origin of congenital left-ventricular outflow-tract obstruction defects of the heart: a population-based case-control study

The aim of our project was to study possible etiological factors in the origin of congenital heart defects (CHDs) because in the majority of patients the underlying causes are unclear. Cases with different CHD entities as homogeneously as possible were planned for evaluation in the population-based large data set of the Hungarian Case Control Surveillance of Congenital Abnormalities. Dead or surgically corrected 302 live-born cases with different types of left-ventricular outflow tract obstructive defects (LVOT, i.e., valvular aortic stenosis 76, hypoplastic left heart syndrome 76, coarctation of the aorta 113, and other congenital anomalies of aorta 32) were compared with 469 matched controls, 38,151 controls without any defects, and 20,750 malformed controls with other isolated defects. Medically recorded pregnancy complications and chronic diseases were evaluated based on prenatal maternity logbooks, whereas acute diseases, drug treatments, and folic acid/multivitamin supplementation were analyzed both on the basis of retrospective maternal information and medical records. The results of the study showed the role of maternal diabetes in the origin of LVOT in general, while panic disorder was associated with a higher risk of hypoplastic left heart syndrome and ampicillin treatment with a higher risk of coarctation of the aorta (COA). High doses of folic acid had a protective effect regarding the manifestation of LVOT, particularly COA. In conclusion, only a minor portion of causes was shown in our study; thus, further studies are needed to understand better the underlying causal factors in the origin of LVOT.