RESUMO
OBJECTIVES: To estimate the association between major types of congenital heart defects (CHD) and spontaneous preterm birth, and to assess the potential underlying mechanisms. STUDY DESIGN: This nationwide, registry-based study included a cohort of all singleton pregnancies in Denmark from 1997 to 2013. The association between CHD and spontaneous preterm birth was estimated by multivariable Cox regression, adjusted for potential confounders. The following potential mechanisms were examined: maternal genetics (sibling analyses), polyhydramnios, preterm prelabor rupture of membranes, preeclampsia, and indicators of fetal and placental growth. RESULTS: The study included 1 040 474 births. Compared with the general population, CHD was associated with an increased risk of spontaneous preterm birth, adjusted hazard ratio 2.1 (95% CI, 1.9-2.4). Several subtypes were associated with increased risks, including pulmonary stenosis combined with a septal defect, 5.2 (95% CI, 3.7-7.5); pulmonary stenosis or atresia, 3.1 (95% CI, 2.4-4.1); tetralogy of Fallot 2.5 (95% CI, 1.6-3.8); coarctation or interrupted aortic arch 2.2 (95% CI, 1.5-3.2); and hypoplastic left heart syndrome, 2.0 (95% CI, 1.0-4.1). Overall, preterm prelabor rupture of membranes mediated more than one-half of the association. Maternal genetics, polyhydramnios, or indicators of fetal or placental growth did not explain the reported associations. CONCLUSIONS: CHD, especially right ventricular outflow tract obstructions, were associated with an increased risk of spontaneous preterm birth. The risk was carried by the CHD and not by maternal genetics. Moreover, preterm prelabor rupture of membranes was identified as a potential underlying mechanism.
Assuntos
Cardiopatias Congênitas/epidemiologia , Nascimento Prematuro/epidemiologia , Adulto , Estudos de Coortes , Dinamarca/epidemiologia , Feminino , Ruptura Prematura de Membranas Fetais/epidemiologia , Humanos , Masculino , Gravidez , Atresia Pulmonar/epidemiologia , Estenose da Valva Pulmonar/epidemiologia , Sistema de Registros , RiscoAssuntos
Cardiopatias Congênitas , Nascimento Prematuro , Feminino , Humanos , Recém-Nascido , GravidezRESUMO
OBJECTIVES: To estimate the association between congenital heart defects (CHD) and indices of fetal growth in Down and 22q11.2 deletion syndromes. STUDY DESIGN: We established 2 Danish nationwide cohorts of newborn singletons with either Down syndrome (n = 670) or 22q11.2 deletion syndrome (n = 155), born 1997-2011. In both cohorts, we analyzed the association between CHD, CHD severity, and indices of fetal growth by multivariable linear regression adjusted for potential confounders. We report mean differences in gestational age specific z-scores compared with newborns without CHD. RESULTS: Down syndrome and 22q11.2 deletion syndrome were both associated with lower mean birth weight and head circumference z-scores. We found no association between CHD or CHD severity and indices of fetal growth. In Down syndrome, the association between any CHD and the mean difference in head circumference z-score was 0.03 (95% CI -0.12, 0.18), and the estimate regarding birth weight z-score was 0.09 (95% CI -0.08, 0.25). The corresponding estimates in 22q11.2 deletion syndrome were 0.00 (95% CI -0.33, 0.32) and -0.09 (95% CI -0.45, 0.26). CONCLUSIONS: We found no association between CHD and fetal growth measures in newborns with Down syndrome or 22q11.2 deletion syndrome. Thus, in certain subtypes of CHD, the contribution of genetic factors to prenatal growth impairment may be more important than circulatory disturbances.