Parents who use Johnson and Johnson’s “No More Tears” baby shampoo could get a visit from a social worker asking questions about illegal drug use, according to a surprising new study at the University of North Carolina, Chapel Hill. Researchers say baby shampoos and other soaps used to wash newborn babies may cause infants to test positive for marijuana.
Researchers found that urine samples from babies washed with any of five baby soaps — Johnson & Johnson’s Head-to-Toe Baby Wash, J&J Bedtime Bath, CVS Night-Time Baby Bath, Aveeno Soothing Relief Creamy Wash and Aveeno Wash Shampoo — tested positive for tetrahydrocannabinol (THC), the active ingredient in marijuana.
“We have identified commonly used soap and wash products used for newborn and infant care as potential causes of false positive THC screening results. Such results in this population can lead to involvement by social services or false child abuse allegations,” the researchers reported in the journal of Clinical Biochemistry. “Given these consequences, it is important for laboratories and providers to be aware of this potential source for false positive screening results and to consider confirmation before initiating interventions.”
Twelve states consider prenatal exposure to any illegal drug, including marijuana, as child abuse.
The researchers began their investigation after nurses at the UNC Chapel Hill nursery reported an unusually high number of infants testing positive for marijuana. Screening of newborns for illegal drugs is not uncommon among populations where there is a high risk of drug use. Positive results can trigger an investigation by child welfare authorities.
Researchers mixed drug-free urine samples with various products and materials found in the nursery to see which ones tested positive for THC. Shampoos were eventually found to be the cause.
The problem is not limited to the five soaps identified in the study. Researchers say any soap or shampoo containing the chemicals polyquaternium-11 and cocamidopropyl betaine could elicit positive marijuana test results. They don’t know why the chemicals interfere with the test, but believe small amounts of soap wash off the babies’ skin and contaminate their urine samples. More sophisticated testing can distinguish between true and false positives, but those tests are rarely ordered because of the cost involved.