Postnatal toxicity of carbon monoxide after pre- and postnatal exposure

Rats were exposed prenatally through 21 days postnatally to 230 ppm carbon monoxide (CO). Offspring weights at 1 day and 5 days were depressed, and values for carboxyhemoglobin, hematocrit, hemoglobin, and heart weight: body weight ratio were elevated, compared to controls. At 21 days survival was markedly reduced in CO-exposed rats (36%) compared to controls (94%). These results, in view of other studies involving only prenatal or neonatal exposure at higher CO levels, suggest that neonatal and postnatal toxicity of CO may be enhanced by prenatal exposure.