Neonatal development altered by maternal sulfur dioxide exposure

Sulfur dioxide (SO2) is one of the commonly encountered environmental contaminants. Experiments were carried out to test for neonatal behavioral alterations associated with maternal SO2 exposure. Pregnant CD-I mice were exposed to 0, 32, or 65 PPM SO2 in environmental chambers from gestation day 7 to 18 (plug = day 1). The SO2 air flow was set at 500 ml/min. Food and water were available at all times. The dams were allowed to deliver and neonatal behavioral development of the pups was studied. Maternal SO2 exposure did not affect the mean number of live pups born/litter; however, the exposure at the high level significantly decreased the mean pup weight on day 1 of birth. SO2 exposure at both levels significantly increased the time required for the righting reflex on day 1 of birth and negative geotaxis on day 10 of birth. The SO2 exposure did not affect the aerial righting score of the pups on day 12 of birth. The data suggest that maternal SO2 exposure can affect the neuromuscular coordination and may produce deficits in the functional capability of the developing offspring. The functional deficits appear to be associated with the birth weight of the offspring.