Behavior problems associated with exposure to phthalates before birth.

Engel, SM, A Miodovnik, RL Canfield, C Zhu, MJ Silva, AM Calafat and MS Wolff. Prenatal phthalate exposure is associated with childhood behavior and executive functioning. Environmental Health Perspectives http://dx.doi.org/10.1289/ehp.0901470.

A new study has found an association between children’s potential for developing disruptive behavior disorders and exposure before birth to the types of phthalates found in fragrances, shampoos, lotions and cosmetics.

The pregnant women who had higher levels of these chemicals in their urine during their third trimester of pregnancy were more likely to have a child who scored below average on behavior and executive functioning tests at 4-9 years of age. The test scores are known to be correlated with clinical diagnoses of behavior or conduct problems and attention-deficit hyperactivity disorders.

This is the first study to examine prenatal exposures to the phthalates and behavior in children. It is among a few studies that are beginning to show a relationship between phthalates and increasing rates of behavioral and neurodevelopmental disorder in children.

The results raise concerns about exposure to phthalates and suggests that exposure to lotions, shampoos and other personal care products during pregnancy may lead to effects on the development of the fetus.

Phthalates are a wide class of chemicals used in many household and consumer products. Phthalates can be grouped according to their size. Some types – the small phthalates – are routinely found in pesticides and personal care products, including many shampoos, fragrances and cosmetics. Other types – the large phthalates, such as DEHP – soften plastics and are found in plastic tubing, some soft toys and construction materials such as vinyl flooring and wall coverings.

Exposure through breathing, eating or skin contact is common due to their widespread use. They do not have long lifetimes in the body but metabolites have been measured in urine, blood, amniotic fluid and breast milk. Prior animal and human research have linked the additives to health effects, including reproductive changes in boys and behavorial problems.

Scientists monitor exposure to these chemicals by looking for their metabolites in urine. The researchers used this approach. They measured the levels of phthalates in the urine of pregnant women who were participating in the Mount Sinai Children’s Environmental Health Study. Parents completed a  standardized questionnaire and survey that assessed their children's cognitive and behavioral development between the ages of 4 and 9.

In general, they found that children whose mothers had higher levels of the low-molecular weight phthalates in their blood during the third trimester of pregnancy had conduct, aggression and attention deficits in later childhood. Some of the effects of these chemicals appeared to be greater in boys than girls – especially aggression, attention problems and hyperactivity.

Other types of phthalates – the high-molecular weight phthalates – more commonly used in tubing and vinyl flooring did not appear to impact cognition and behavior.

Previous studies have found links between phthalate exposure and alterations in circulating levels of thyroid hormones. These hormones are essential to normal development, including brain and sexual development, and this is particularly important in children. Thus, the results may be related to alterations in thyroid hormone homeostasis.

Although social factors were statistically controlled for, the study relied on parent memories and reporting. The authors suggest further research in this area, and if necessary, measures to reduce exposure.