Air Pollution Affects Babies Worst During Second Trimester

Women who are exposed to significant levels of air pollution, especially during their second trimester, are more likely to give birth to children who have asthma, researchers have determined.

According to the findings of a new study presented at the 2014 American Thoracic Society International Conference, of all windows of time during pregnancy, the second trimester is when unborn children are most susceptible to the pollutants that their mother's breath.

"We know that mothers' exposure to air pollution during pregnancy can affect lung development of their babies and lead to subsequent respiratory disorders, including asthma, although little is known about whether timing of the exposure is important to consider," lead author Yueh-Hsiu Mathilda Chiu said in an American Thoracic Society (ATC) release.

To determine that the second trimester is when unborn children are most vulnerable, Chiu and her team followed 430 mother-child pairs before and after birth for seven years. They measured high risk air pollutants these mothers experienced while pregnant, focusing on automotive and industrial sources in particular, as these types of air pollutants have been identified as fine-but-toxic particulates that can be inhaled deep into the lungs - resulting in the greatest health risks.

Researchers found that even compared to children of women who face the greatest overall exposure to pollutants, children who were exposed to the highest concentration of pollutants during the second trimester were the most likely to develop lung conditions like asthma.

This news comes in the wake of a recent World Health Organization (WHO) report, which showed that while more countries are concerned about air quality, only one in 10 urbanites across the world are breathing air that meets recommended safety levels.

Studies presented at any conference are generally viewed as preliminary findings until they have been published in a peer-reviewed scientific journal.