Effect of chronic maternal exposure to low carbon monoxide concentrations on the foetus

The effect of maternal exposure to low carbon monoxide concentrations, throughout gestation, was studied in 21 pregnant Buscat rabbits and was compared with seven pregnant controls. Exposure of pregnant rabbits to 100 p.p.m. CO [parts per million by volume] in atmospheric air resulted in a mean maternal carboxyhaemoglobin level of 10.6% and a mean foetal level of 15.4% compared to control values of 1.1 and 1.3% maternal and foetal carboxyhaemoglobin in non-exposed animals. A significant increase in resorption sites and intrauterine foetal deaths and a significant reduction in the litter size and in foetal birth weght was demostrated in carbon monoxide-exposed animals when compared with controls. Neuropathological changes were observed in the foetal brain in 7% of co-exposed foetuses