Baby lotion, powder and shampoo can lead to higher concentrations in an infant's body of phthalates, chemicals linked to allergies and altered reproductive development, a study showed.
The study conducted at the University of Washington and Seattle Children's Hospital Research Institute found that babies treated with common infant care products such as lotion, shampoo, and powder were more likely to have phthalates in their urine than other babies.
Researchers at the university measured the levels of nine different phthalates in urine samples collected from 163 infants, aged two months to 28 months, and had the babies' mothers fill out questionnaires on their use of infant care products in the previous 24 hours.
The scientists found that at least one phthalate was present in every baby's urine sample, and that using baby powder, lotion and shampoo were strongly associated with higher phthalate levels in the urine.
"This is troubling, because phthalate exposure in early childhood has been associated with altered hormone concentrations as well as increased allergies, runny nose, and eczema," said the study's lead author Sheela Sathyanarayana, a professor of pediatrics at the University of Washington medical school.
Animal-based studies of phthalates have found that the synthetic chemicals can harm reproductive system development, and studies in humans have found that prenatal exposure or exposure through breast milk can alter hormone concentrations, the study says.
"Babies may be more at risk than children or adults because their reproductive, endocrine and immune systems are still developing," Sathyanarayana said.
Phthalates are man-made chemicals commonly found in personal care and other household products, including plastic children's toys, lubricants, and chemical stabilisers in cosmetics and personal care products.
In 2006, the European Union banned the use of six phthalate softeners in polyvinyl chloride toys designed to be placed in the mouth by children younger than three.
More research is needed to determine if exposing very young children to phthalates is linked with reproductive or other problems, says the study, which was published in the scientific journal Pediatrics.