Pregnant women, who are exposed to higher levels of common chemicals such as phthalates are at a greater risk of delivering premature babies, according to a University of Michigan School of Public Health and Brigham and Women's Hospital in Boston study.

The researchers said that phthalates can be found in a variety of common products such as lotions, perfumes and deodorants. Contaminated food and water also contain the chemical.

Apart from causing preterm births, phthalates is also known to cause disrupted thyroid hormone levels, breast cancer and the uterine disorder known as endometriosis.

"Preterm birth is a major public health challenge. Rates are significantly higher than they were 20 years ago and we don't know why. Other interventions have had limited effectiveness, and this helps shed light on a potential for environmental influences," John Meeker, associate professor of environmental health sciences and associate dean for research at the U-M School of Public Health and the principal investigator of the study said in a statement.

"Next, we need to look at how pregnant women are exposed, and at what stage of pregnancy, to help inform exposure and risk prevention strategies."

For the study, the scientists compared 130 women who had a preterm delivery (before 37 weeks of pregnancy) with 352 women who had a normal delivery at the Brigham and Women's Hospital from 2006-08. Phthalate levels were measured in urine samples taken three times during pregnancy. The 130 mothers who delivered prior to 37 weeks showed significantly higher concentrations of phthalate-linked compounds or 'metabolites.'

"This is by no means the cause of premature birth, but it is a possible contributor-which is important because it is potentially modifiable," Dr. Thomas McElrath, a physician-scientist and key co-investigator on the study said in the statement. "This finding may be dramatic but women should not be alarmed. This is only the first step in a long research process that will be needed to clarify and confirm these results. It is simply too early to suggest making changes in prenatal care based on this study."

The finding has been published online Nov. 18 in the journal JAMA Pediatrics.