Research published Tuesday morning adds to the evidence that exposure to the ubiquitous chemicals called phthalates may be harmful to humans.

Phthalates, used in a vast variety of plastic products (to make them more pliable), cosmetics and even clothing such as raincoats, have been for some time suspected of causing health problems, though as this CDC report notes, research directly linking phthalates exposure to human health outcomes has been sparse.

A small study conducted by researchers at Columbia University’s Mailman School of Public Health and published in the journal Environmental Health Perspectives measured levels of four kinds of phthalates in the urine of 319 non-smoking pregnant women. When the children born of those pregnancies were three years old, the researchers assessed their mental, motor and behavioral development.

The study found that phthalates exposure during pregnancy was associated with increased risk of motor delay, a condition that could potentially translate to problems with fine and gross motor skills later in life, according to the study. One of the phthalates was associated with “significant” decreases in mental development among girls; among boys and girls, three of the phthalates were associated with behavior problems such as anxiety and depression, “emotionally reactive behavior” and withdrawn behavior.

Though phthalates may interfere with the body’s endocrine system, the study notes that science has not established a clear mechanism of action explaining how the chemicals might harm the body. Given that and other limitations of the study, the authors conclude that their findings “raise a public health concern,” but “should be interpreted with caution,” adding that additional research is warranted.