Thimerosal exposure (from tetanus-diphtheria vaccine) during pregnancy and neurodevelopment of breastfed infants at 6 months.
OBJECTIVE
We studied the effect on neurodevelopment of infants who are exposed to thimerosal in tetanus-diphtheria (Td) vaccines during pregnancy.


METHODS
We compared Gesell Developmental Schedules (GDS) of exclusive breastfed infants at 6 months born to mothers who received Td (1 to 3 doses) against those who were born to mothers who did not take such vaccines.


RESULTS
Compared with the group of infants not exposed to ethylmercury in utero, the infants of exposed mothers showed no significant difference in neurodevelopment delays. Although there was a significant correlation between hair-Hg of mothers and hair-Hg of neonates (Spearman r = 0.353; p = 0.0011), there was no significant correlation between the level of in utero exposure to ethylmercury in Td vaccines and neonate's hair-Hg concentrations (Spearman r = 0.060; p = 0.5922). However, regression analysis showed that GDS at 6 months was significantly associated with total mercury concentration of neonate's hair but was not sensitive to the number of vaccines taken by the mother.


CONCLUSIONS
Early neurodevelopment of exclusively breastfed infants is sensitive to in utero exposure to mercury, but maternal thimerosal exposure in tetanus-diphtheria vaccines per se cannot portend clinical neurodevelopment delays measured by GDS at 6 months.
Marques
R C
RC
Fundação Universidade Federal de Rondônia. Porto Velho, RO, Brasil.
Dórea
J G
JG
Bernardi
J V E
JV
D000293:Adolescent; D000328:Adult; D001942:Breast Feeding; D002658:Developmental Disabilities / Q000139:chemically induced*; D004168:Diphtheria Toxoid / Q000009:adverse effects; D005260:Female; D006197:Hair / Q000737:chemistry; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009483:Neuropsychological Tests; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D012044:Regression Analysis; D013745:Tetanus Toxoid / Q000009:adverse effects; D013849:Thimerosal / Q000009:adverse effects* / Q000032:analysis; D055815:Young Adult
D004168:Diphtheria Toxoid; D011310:Preservatives, Pharmaceutical; D013745:Tetanus Toxoid; D013849:Thimerosal