Heart defects in children linked to environmental toxin exposure during pregnancy

A study shows that environmental toxin exposure during pregnancy is linked with heart defects in children.

Congenital heart defects in children may be associated with a mother's exposure to specific mixtures of environmental toxins during pregnancy, according to research recently presented at the Scientific Sessions conference sponsored by the American Heart Association.

Congenital heart defects occur when the heart or blood vessels near the heart fail to develop normally before birth. Defects may be caused by chromosomal abnormalities, but the cause is unknown in most cases, according to the research.

Researchers examined patterns of congenital heart defects incidence and presence of environmental toxins in Alberta, Canada. The ongoing research seeks to determine if pregnant women’s proximity to organic compounds and metals emitted in the air impacts the risk of heart defects in their children.

“Although still in the early stage, this research suggests some chemical emissions -- particularly, industrial air emissions -- may be linked to heart abnormalities that develop while the heart is forming in the womb,” said lead researcher Dr. Deliwe P. Ngwezi, a student and research fellow in pediatric cardiology at the University of Alberta in Canada.

The study is based on congenital heart defects diagnosed in 2004 through 2011 and chemical emissions recorded by a Canadian agency tracking pollutants.

Researchers looked at three chemical categories, but only one group showed a strong correlation with rates of congenital heart defects.

Ngwezi said the group of chemicals consists of a mixture of organic compounds and metals namely: benzene, butadiene, carbon disulphide, chloroform, ethylene oxide, hexachlorobenzene, tetrachloroethane, methanol, sulphur dioxide, toluene, lead, mercury and cadmium.

Congenital heart defect rates have gradually decreased in Canada since 2006, which is about the time the government tightened regulations to reduce industrial air emissions, Ngwezi said.

The heart defect decreases were mainly associated with heart defects resulting in holes between the upper and lower heart chambers and malformations of the cardiac outflow tracts Ngwezi said.

“For now, consumers and health care providers should be educated about the potential toll of pollutants on the developing heart,” she said. “As we have observed in the preliminary results, when the emissions decrease, the rates of congenital heart defects also decrease.”

This study, she said, should draw attention to the increasing evidence about the impact of environmental pollution on birth defects.

Limitations of the study include that observations were made at a group level, not according to individual risk and the self-reported industry data that is monitored and collected annually by the government, Ngwezi said.

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Pediatric migraines may be caused by environment

Different environmental factors, such as sleep deprivation, diet, and school, could play a role in pediatric migraines.

Environmental stressors play a large role in triggering migraines in children, according to Dr. Eric Pearlman.

"Migraine is definitely a pediatric disorder. It peaks in young adulthood, but it definitely occurs in kids," Dr. Pearlman, chair of the department of pediatrics at Mercer University in Savannah, Ga., said at the annual meeting of the American Academy of Pediatrics.

Epidemiologic data suggest that migraine occurs in 10.5% of 10- to 15-year-old children and 3% of 7-year-olds, and that headaches – possibly including migraines – occur in 4% of 3-year-olds. By about 13 years of age, the prevalence of migraines starts reaching adult levels of about 6% in males, and 18% in females.

Environmental factors such as sleep deprivation, dehydration, dietary factors, school stressors, hidden stressors (like peers), and hormonal fluctuations represent triggers that can be particularly pronounced in children, he noted.

With International Classification of Headache Disorders, third edition (ICHD-III) criteria, migraines can be differentiated from acute, acute recurrent, and chronic progressive or chronic nonprogressive headaches if a child has experienced at least five attacks lasting up to 72 hours (whether untreated or unsuccessfully treated), if nausea and/or vomiting or photophobia and phonophobia are present, and if the child has at least two of four characteristics, including unilateral location, pulsating quality, moderate to severe intensity, and a tendency to be aggravated by – or avoid – routine physical activity.

In children, photophobia and phonophobia can be inferred (if they report having to lie down in a dark, quiet room, for example), as many have difficulty describing or understanding these symptoms

Unilateral headaches are rare in children, Dr. Pearlman noted.

If a diagnosis of migraine is established, it is important to make the diagnosis known to the child, and to educate the child about the condition and treatments.

Consider providing handouts and referring to websites (such as theAmerican Headache Society or the National Headache Foundationsites), to help educate patients and to manage their expectations, as they need to understand you cannot cure their migraine, he advised.

Involving both the patient and their parents in decision making can improve compliance with treatment recommendations, he said.

Pharmacologic interventions can include nonspecific short-term therapies, migraine-specific therapies, and preventive treatment.

Nonspecific short-term therapies may include acetaminophen, nonsteroidal anti-inflammatory drugs, or combination drugs. Migraine-specific therapies include ergotamine and dihydroergotamine, and the "triptans."

Seven triptans are available, including two that are approved for use in children; rizitriptan (Maxalt) is approved for children older than age 6 years, and almitriptan (Axert) is approved for those aged 12-17 years.

Maxalt comes in both an oral and orally disintegrating form, and is available as a generic drug. Generic sumitriptan (Imitrex) also is available.

"There are good data for most of the triptans for adolescents aged 12 and older," Dr. Pearlman said.

Rescue medications for those who have an inadequate response to short-term therapy can include a combination of an analgesic like a nonsteroidal and an antiemetic, or an opiate and an antiemetic if the patient used a nonsteroidal initially. Rescue medications may be needed "because nothing is going to work 100% of the time," he said.

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