Baby shampoos, lotions and powders may expose infants to phthalates, a class of chemicals that has been linked with reproductive problems, a small U.S. study suggests.

Phthalates (pronounced thowl-ates) are synthetic, man-made chemicals used to stabilize fragrances and make plastic bottles flexible. The study found that babies may be absorbing these chemicals into their systems.

Health Canada said in a statement that no children's toiletry products in Canada list phthalates as ingredients, and the agency says it's working on replacing a current voluntary ban on the chemical with a permanent one.

U.S. researchers tested the urine of 163 infants aged two to 28 months, 24 hours after they were shampooed with the baby shampoos, wiped with baby wipes, and had baby lotions, powders and diaper creams applied. (The name brands of the baby products the parents used were not recorded by the study authors.)

All of the urine samples contained at least one phthalate, and 80 per cent of the samples had measurable amounts of at least seven types of phthalates:

• Exposure to lotion led to higher concentrations of the metabolite monoethyl phthalate (MEP) -- which forms after exposure to diethyl phthalate (DEP) -- and monomethyl phthalate (MMP) -- which forms after exposure to dimethyl phthalate (DMP)
• Exposure to shampoo also led to higher concentrations of monomethyl phthalate
• Exposure to powder led to higher concentrations of monoisobutyl phthalate (MiBP) -- formed after exposure to di-isobutyl phthalate (DiBP)

Neither diaper cream nor infant wipe use was strongly associated with concentrations of any of the phthalate metabolites.

The more products that were used, the greater the concentration of phthalates were found. The study also found that the highest levels were most prevalent in babies younger than eight months.

The study results are found in the latest issue of Pediatrics.

Phthalates are thought to alter reproductive development. Animal studies have suggested they can cause reproductive birth defects, but their effect on humans is less well understood. Infants are considered more vulnerable to developmental and reproductive toxicity of phthalates given their immature metabolisms, the study said.

The study's lead author, Dr. Sheela Sathyanarayana, a University of Washington pediatrician, says the study was not able to offer direct evidence that the products used on the infants contained phthalates, nor could they prove that the chemicals in the babies' urine caused any harm.

Sathyanarayana notes that phthalates do not build up in the body the way certain other chemicals, such as PCBs, do.

"They are excreted in a matter of hours, to a day or so," she tells CTV. "But the issue is daily and repeated exposure, because we often use these products daily."

Family physician and consultant for Environmental Defence, Dr. Kapil Khatter, says he finds the results worrisome.

"It shows that phthalates are everywhere in terms of baby shampoo, lotions, all kinds of products from all kinds of different roots all the time. It is also important because it shows that you can absorb phthalates through your skin," he told CTV News.

"It also confirms what we thought: the younger you are the more vulnerable you may be. So a younger infant will have a higher body weight of phthalates after using the same amount of lotion and the same amount of shampoo."

Canada on phthalates

Health Canada says it's "taking action" on phthalates to protect young children.

"As it stands, no children's toiletry products in Canada list phthalates as ingredients," said the agency in a statement.

"Health Canada is nevertheless conducting a study to determine whether even trace amounts of phthalates can be found in a wide range of cosmetics, particularly fragrances used in soaps, shampoos and creams intended for infants."

• Read Health Canada's entire statement here.

In 2006, the European Union banned the use of six phthalate softeners in polyvinyl chloride toys that children younger than three may put in their mouth. But in the United States and Canada, there is no requirement that products be labelled as to their phthalate content.

As well, fragrances are considered a common source of phthalates, yet retail products aren't required to list the individual ingredients of fragrances.

"Parents may not be able to make informed choices until manufacturers are required to list phthalate contents of products," the study authors note.

"If parents want to decrease exposures, then we recommend limiting amount of infant care products used and not to apply lotions or powders unless indicated for a medical reason," the authors conclude.