Phenols are commonly used in cleaning products and cosmetics. They are generally considered safe in small amounts. Some phenols are considered as endocrine disruptors because of their estrogen-like activities. Exposure to them is believed to be one of the reasons for the recent rise in allergic diseases such as asthma. However, the actual clinical association between maternal exposure to phenols during pregnancy and the development of asthma in children remains unclear. Therefore, researchers in Japan conducted a study to prove this hypothesis.
Researchers collected urine samples during the first trimester of pregnancy from 3,513 mothers and measured the concentrations of 24 phenols. They also examined the association between phenol concentrations in these samples and the development of asthma in their children at the age of 4.
Results showed that most urine samples included high mean values of methylparaben, ethylparaben and propylparaben. The researchers found that the maternal group with the top 10% butylparaben in their urine had a significantly higher risk of the development of asthma in their children compared with the rest of the group.
They additionally observed asthma rates greater than 1% for samples with isopropylparaben, butylparaben, 4-t-octylphenol, 4-nonylphenol, triclocarban and bisphenol S compared with samples that did not include these phenols.
Since phenol is known to have estrogenic effects, the researchers examined the effects of phenol exposure by gender. The results showed that male children born to mothers with 4-nonylphenol had a higher risk of developing asthma.
In conclusion, the study confirmed that maternal exposure to high levels of butylparaben early in pregnancy was clearly associated with the development of asthma in children. Maternal exposure to 4-nonylphenol also increased the risk of asthma in boys. This study provides a valuable basis for developing recommendations regarding phenol exposure during pregnancy.
