22 February 2013. More than 40 solvents are known to cause toxicity to the brain, but medical reports on neurological symptoms mainly regard adults. Because the chemical properties of solvents make them capable of passing into the brain, and through the placenta, their possible toxicity to the developing brain should be a serious concern. So far, the main evidence on neurotoxicity relates to toluene, because this solvent has been used for sniffing. Much of the literature on occupational exposures regards mixtures of solvents, where it is not possible to determine how much each solvent contributed to the damage.

A new report from France now links women’s exposures during pregnancy to solvents at work to their children’s development at age two years. At this age, cognitive testing can be challenging and may not reveal much about a child’s later development. So the researchers focused on behavioral assessment. If the mother was exposed to solvents at work, the child had a greater risk of attention deficits and aggressive behavior, as determined by questionnaire. More frequent exposure also resulted in greater abnormalities. Still, although highly plausible, the results must be considered preliminary, as the long-term implications are unknown. Hopefully, future follow-up of the 3,000 children in Brittany will provide more solid data on the extent of any solvent-related brain drain.

What is particularly worrying about this report is that one out of five women reported solvent exposures while they were pregnant, and that this happened in common jobs, such as nurse or other hospital employee, chemist, cleaner, hairdresser, and beautician. Measurement of solvent breakdown products in the urine confirmed the women’s own reports on being solvent-exposed. About half of the women worked throughout the first two semesters (the first 28 weeks) of the pregnancy.

This study deserves to be extended and replicated, so that we can get a better understanding of solvents as brain drainers. In the meantime, we should prevent solvents from coming near any developing brains. A US colleague recently suggested that pregnant women should not be responsible for filling the car at the gas station. That would be an easy first step.