The effects of seafood contaminants in maternal diet during pregnancy on neonatal neurologic function were examined in 182 singleton term births in the Faeroe Islands, and reported from the Institute of Public Health, Odense University, Denmark. Maternal serum, hair, and milk and umbilical cord blood were analysed for contaminants, Each infant’s neurologic optimality score (NOS) was determined at 2 weeks of age and adjusted for gestational age. Exposures to methylmercury and polychlorinated phenols and cord blood fatty acid concentrations were increased in proportion to maternal seafood intake. Thyroid function tests were normal. A 10-fold increase of cord-blood mercury concentration was correlated with a decrease in NOS of 2.0 (P= .03). [1]

COMMENT. Increased exposures to methylmercury from maternal seafood intake are associated with a significant decrease in neonatal neurologic optimality scores and an increased risk of neurodevelopmental deficit. The NOS used in this study is based on the Prechtl exam technique and includes functional abilities, reflexes and tone, and behavior. The NOS is the number of items rated optimal out of 60. In the Faeroe Islands, whale meat is the source of methylmercury in the diet. For previous reports of neuropsychological effects of methylmercury and PCP exposures see Progress in Pediatric Neurology III, PNB Publ, 1997;pp278-280.

Iatrogenic exposure to mercury after hepatitis B vaccination in preterm infants is reported by Stajich GV et al. [2]. Thimerosal, a mercury-derived preservative, has been used in some vaccines since the 1930s. Thimerosal is composed of 49.6% ethylmercury, which behaves like methylmercury. According to a review editorial by Pless R and Risher JF [3], infants may be exposed to cumulative doses of mercury from vaccines in the first 6 months, exceeding the EPA limit of 0.1 mcg/kg/d for chronic daily exposure to methylmercury. The Advisory Committee on Immunization Practices has recommended that hepatitis B vaccine used in infants at birth should not contain thimerosal.