New research from the University of Michigan School of Public Health has linked chemicals known as phthalates with complications of pregnancy and fetal development.

In recent years, scientists have linked chemicals known as phthalates with complications of pregnancy and fetal development.

Phthalates are chemicals used to make plastic materials more flexible and can also be found in personal care products such as perfumes, deodorants and lotions. They can enter the human body by being ingested, inhaled or through the skin. Most often phthalates are metabolized and excreted quickly, but constant contact with them means that nearly everyone in the United States is exposed, some more than others.

For the study, Meeker and his colleagues tested urine samples from nearly 500 pregnant women in the Boston area and found an association between the presence of phthalates and increased levels of biomarkers of oxidative stress.

Oxidative stress occurs when there is an imbalance between free radicals (oxygen containing molecules with one or more unpaired or "dangling" electrons) and the antioxidants that defend against them. Such imbalances have been associated with a number of adverse health conditions.

"It is not fully known what the impacts of increased oxidative stress on pregnancy might be, but this is an active area of research," researcher John Meeker said in a statement. "We recently showed in another analysis among the same cohort of women that biomarkers of oxidative stress were associated with increased risk of preterm birth. Other effects, such as adverse fetal development and maternal health complications, may also be related to oxidative stress."

Nine phthalate metabolites were measured to determine exposure levels, and two markers found to be indicative of oxidative lipid and DNA damage, known as 8-hydroxydeoxyguanosine and 8-isoprostane, respectively, also were measured.

"We found that the links between these two sets of biomarkers were very strong when adjusting our analysis for other important factors." Meeker said. "We plan to conduct more in-depth studies to shed light on how exactly this may be occurring, and the full downstream consequences of these findings."

The findings are detailed in the online journal Environmental Health Perspective.