Maternal exposure to phthalates during pregnancy is linked to lower IQ in kids

pregnant belly
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This new study provides yet another reason to stay away from plastics and scented products as much as possible.

A new study has found that prenatal exposure to phthalates may have a significant negative impact on children’s IQ levels by age 7. Women who were exposed to the highest levels of two common household chemicals – di-n-butyl phthalate (DnBP) and di-isobutyl phthalate (DiBP) – during pregnancy had children whose IQ scores measured 6 points lower on average than those women whose exposure was reduced.

Researchers followed 328 inner-city mothers and their children who were born between 1998 and 2006. Urine samples were taken during the last trimester of pregnancy to measure phthalate content, and the children were followed up with interviews and testing at ages 3, 5, and 7.

The measurement for child IQ was based on four areas of mental functioning – the Verbal Comprehension Index, the Perceptual Reasoning Index, the Working Memory Index, and the Processing Speed Index. Researchers controlled for factors such as maternal IQ and education levels, and quality of the home environment, which are known to affect child IQ levels.

Researchers found that the children of mothers exposed during pregnancy to the highest 25 percent of concentrations of DnBP and DiBP had IQs 6.6 and 7.6 points lower, respectively, than children of mothers exposed to the lowest 25 percent of concentrations.

“A six- or seven-point decline in IQ may have substantial consequences for academic achievement and occupational potential,” says senior author Robin Whyatt.

The study’s lead author Pam Factor-Litvak points out that pregnant women in the United States are exposed daily to phthalate levels that are similar to those measured in this study.

“While there has been some regulation to ban phthalates from toys of young children, there is no legislation governing exposure during pregnancy, which is likely the most sensitive period for brain development. Indeed, phthalates are not required to be on product labeling.”

Phthalates, which are described as “a class of high production chemicals widely used as plasticizers and additives in consumer and personal care products,” are known endocrine disruptors that cause perturbations in thyroid hormones, testosterone levels, and the neurotransmitter dopamine, which, Factor-Litvak says, is “linked to inattention and hyperactivity.”

Phthalates are found in many soft plastics, scented products such as air fresheners and dryer sheets, recyclable plastics labeled as 3, 6, or 7, and can leach into food that is microwaved in plastic. All of these things are best avoided during pregnancy, and glass containers should be used in place of plastic whenever possible.

Persistent Associations between Maternal Prenatal Exposure to Phthalates on Child IQ at Age 7 Years” was published on December 10, 2014 in the online journal PLOS One.

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