Pregnant women who are exposed to higher levels of an increasingly controversial chemical in certain plastics may deliver their babies slightly earlier than women with less exposure, hints a new study.

"The magnitude of the effects seen," the study team writes in the latest issue of Pediatrics, "might be associated with adverse health effects in newborns."

The chemical, DEHP - short for di (2-ethylhexyl) phthalate - is a "plasticizer" used widely in consumer products to help make vinyl plastic soft and flexible. "Exposures (to DEHP) are ubiquitous," says Dr Robin M. Whyatt from the Columbia Center for Children's Environmental Health in New York City. DEHP breakdown products "have been detected in 95 percent of the general US population".