Moms' plasticizer exposure troubling for baby boys.

Sep 06, 2011

Kim, Y, EH Ha, EJ Kim, H Park, M Ha, JH Kim, YC Hong, N Chang and BN Kim. 2011. Prenatal exposure to phthalates and infant development at six months: Prospective Mothers and Children’s Environmental Health (MOCEH) Study. Environmental Health Perspectives http://dx.doi.org/10.1289/ehp.1003178.

Synopsis by Aimin Chen

A woman's exposure to commonly used plasticizers – called phthalates – during pregnancy may be associated with suboptimal development in babies, finds a South Korean study.

Increasing exposure to plastic-softening chemicals in pregnant women was associated with poorer development in their baby boys, finds a study that examined mental and motor skills in 6-month-old infants.

The results show that the higher the exposure to phthalates in the moms, the lower the scores of infant development, including both cognitive and motor behavior. However, the association was only identified in sons, not in daughters.

Given that phthalates are short-lived in people, reducing exposure in pregnant women will effectively reduce the possibility of fetal exposure to these chemicals. The study is important because it adds more evidence to the growing human health concerns about these chemicals, especially with boys.

Phthalates have many industrial and commercial applications. Some are commonly used in plastics to make them soft, flexible and less brittle. Medical tubing, toys, food containers, flooring and other plastic consumer products can contain them. They also are added to personal care items such as lipstick, nail polish and shampoo. Although phthalates do not accumulate in people, exposure to these potentially hormone-mimicking chemicals occurs every day through food, air or skin.

Animal studies suggest prenatal phthahate exposure may influence neurodevelopment and contribute to hyperactive and impulsive – ADHD-like symptoms – behavior. Similar conclusions were drawn from a study with school-aged children. Other studies identify links between phthalates and social impairments in children.

Phthalates may function as anti-androgens. That is, they block or otherwise thwart male hormones. There is also concern they may disrupt thyroid hormones and contribute to infant developmental problems. Evidence on whether they influence infant behavior is still scarce.

In this study conducted between 2006 and 2009, a group of South Korean investigators examined 460 mothers during pregnancy and their babies six months after birth. They measured the three main metabolites of DEHP and DBP phthalates – MEOHP, MEHHP and MBP – in the mom’s urine sample taken during the third trimester. Metabolites form from the original compounds after chemical changes in the body. They tested infant behavior development using the standardized assessment Bayley Scales of Infant Development. The researchers statisically compared the exposure to phthalates – as measured in the moms' urine – and infant behavior.

Further research is needed to validate these findings and confirm if the behavior patterns persist into childhood.