Abstract
Toxaemia of pregnancy occurs in 1 out of every 10 pregnant non-smokers, compared with 1 out of every 20 smokers. This might be due to the abortifacient effect of smoking, especially in the first trimester, with consequent exclusion of presumptive candidates for toxaemia. Another interesting possibility is that the cyanides included in tobacco smoke are converted to thiocyanates and, theoretically, might offer a certain protection against thrombosis in the placenta and against toxaemia. The perinatal mortality among low-weight newborns (< 2500 g) is much higher among infants of non-smokers, as is the frequency of bleeding and infarction of the placenta. This suggests that the perinatal mortality among low-weight newborns of mothers who are non-smokers is to a larger extent due to toxaemia than is that among infants of smokers.