Association between maternal exposure to gaseous pollutants and atrial septal defect in China: A nationwide population-based study

BACKGROUND

The association between maternal exposure to gaseous air pollutants and congenital heart defects (CHD) remains unclear. The concentration-response relationship and the time windows of susceptibility to gaseous pollutants may vary by pollutant species and CHD subtypes.

OBJECTIVE

We aimed to examine the relationship between maternal exposures to four species of gaseous pollutants (NO₂, O₃, SO₂, and CO) and atrial septal defect (ASD), which is a common subtype of CHD, and to determine the critical time windows of susceptibility for each gaseous pollutant.

METHODS

Among 1,253,633 infants born between October 1, 2013 and December 31, 2016 in China, 1937 newborns were diagnosed with isolated ASD, a prevalence of 1.55‰. Maternal exposures to the gaseous pollutants were estimated by matching the geocoded maternal addresses with the gridded ambient concentrations. The adjusted odds ratios (aOR) between exposures and ASD were quantified by using mixed-effects logistic regression models.

RESULTS

We found significantly positive associations between ASD and maternal exposures to NO₂, O₃, SO₂, and CO during entire pregnancy, first-, second-, and third-trimester. However, no statistically significant association was found between maternal exposure to PM_2.5, PM_2.5-10 and ASD risk (P > 0.05). In the fully adjusted model with respect to average exposure over entire pregnancy, the adjusted odds ratios (aOR) for each 10 μg/m³ increment of NO₂, O₃, SO₂ were 1.33 (95% CI: 1.22-1.45), 1.13 (95% CI: 1.10-1.16), 1.28 (95% CI: 1.20-1.35), respectively; the aOR for each 100 μg/m³ increment of CO was 1.10 (95% CI: 1.06-1.15). The observed concentration-response relationships varied by exposure periods and pollutants, with the strongest association for NO₂ during the 1st-8th embryology weeks, for O₃ during the third trimester, for SO₂ during the second trimester, and for CO without obvious variation.

CONCLUSIONS

The findings suggest an increased risk of ASD in association with maternal exposures to four common gaseous pollutants. From the perspective of birth defects prevention and ASD risk mitigation, it is critical to reduce maternal exposure to gaseous pollutants especially during the most susceptible time windows.

Transient platypnea-orthodeoxia-like syndrome induced by propafenone overdose in a young woman with Ebstein's anomaly

In this report we describe the case of a 37-year-old white woman with Ebstein's anomaly, who developed a rare syndrome called platypnea-orthodeoxia, characterized by massive right-to-left interatrial shunting with transient profound hypoxia and cyanosis. This shunt of blood via a patent foramen ovale occurred in the presence of a normal pulmonary artery pressure, and was probably precipitated by a propafenone overdose. This drug caused biventricular dysfunction, due to its negative inotropic effect, and hypotension, due to its peripheral vasodilatory effect. These effects gave rise to an increase in the right atrial pressure and a decrease in the left one with a consequent stretching of the foramen ovale and the creation of massive right-to-left shunting. In our case this interatrial shunt was very accurately detected at bubble contrast echocardiography.

Atrioventricular septal defect with separate right and left atrioventricular valvar orifices in a patient with foetal hydantoin syndrome

The teratogenic properties of phenytoin, including cardiac malformations, have been previously documented. We report one patient with foetal hydantoin syndrome and atrioventricular septal defect with common atrioventricular junction but separate right and left atrioventricular valves, an association that has not been described, to the best of our knowledge.

Congenital complete absence (bilateral agenesis) of the diaphragm: a rare variant of congenital diaphragmatic hernia

Although congenital diaphragmatic hernia is one of the most common congenital anomalies, complete bilateral absence of the diaphragm is a very rare variant, with six cases reported in the literature. A 1040 g black male infant was born at 27 weeks' gestation to a 28-year-old black woman with a history of minimal prenatal care and cocaine abuse during pregnancy. Apgar scores were 2/1/1/0/1 at 1, 5, 10, 15, and 20 minutes, respectively and efforts to resuscitate him were unsuccessful. He died at 2 1/2 hours of age. Autopsy showed complete absence of the diaphragm, pulmonary hypoplasia, and an atrial septal defect of the heart. Cytogenetic studies showed normal male karyotype. We suggest that decreased or interrupted blood supply to the developing diaphragm of this infant may have interrupted normal embryogenesis in the early developmental stages.

Fetal cardiovascular morphology of interrupted aortic arch type B in rats

Interrupted aortic arch type B associated with ventricular septal defect (n = 17) or atrioventricular septal defect (n = 2) was induced in 19 of 300 fetuses by maternal administration of bis-diamine on the 9th and 10th day of pregnancy. After rapid whole-body freezing on the 21st day, the fetuses were studied by means of serial cross-sectional photographs of the frozen thorax. In fetuses with interrupted aortic arch, the ascending aorta was small, and the ratio of its diameter to the diameter of the pulmonary trunk was 0.64 +/- 0.03 (mean +/- SEM) in contrast to 0.96 +/- 0.02 in the control. The aortic arch was interrupted distal to the left common carotid artery (type B of Cerolia and Patton) in all cases.

Hormonal versus genetic factors in limb and heart anomalies

Three men, aged 18, 21 and 27 years, underwent surgery for atrial septal defect of the ostium secundum. All had bilateral absence of the forearm and thumb, with the rest of the hand directly attached to the upper arm. The patients had been exposed to synthetic progestogens during early intrauterine development. The oldest patient is described, together with a 6-year-old boy with limb reduction and Fallot's tetralogy who was exposed to the contraceptive pill during the first 2 months of gestation. During surgery he was found to have atrial septal defect of the ostium secundum. The most plausible diagnosis in such cases is the Holt-Oram syndrome, but the teratogenic effect of the synthetic hormones may be an important aetiological factor. Both hypotheses are discussed.

Severe cardiac and ophthalmologic malformations in an infant exposed to diphenylhydantoin in utero

A newborn male infant with multiple congenital malformations including lethal cardiac malformations and severe ophthalmic malformations is described. The infant was exposed in utero to hydantoin. There is no other identifiable cause for the malformations apparent in the infant's or his family's history.

[Cardiovascular malformations in embryofetal alcohol syndrome (author's transl)]

17 infants and children with embryofetal alcohol syndrome were examined of cardiovascular malformations. In 8 cases heart catheterization revealed malformations, mainly atrial septum defects (in 5 of 8 cases), only in one case a ventricular septum defect, in another case an aplasia of the right pulmonary artery and in one case a mild outflow tract obstruction of the left ventricle. Congenital heart diseases can be expected in nearly 50% of the cases in embryofetal alcohol syndrome.