Structural changes in the placenta of smoking mothers: a quantitative study.

Placentae of matched pairs of smoking and non-smoking mothers have been investigated by quantitative light microscopic techniques. A smaller diameter of the villous capillaries, a decrease in vasculosyncytial membranes and basement membrane thickening were observed in the placenta of smoking mothers. Quantitative morphometric methods showed a significant decrease in volume density of the fetal vessels in the terminal villi of the smoker's placenta. The exchange area of the smoker's placenta was shown to be decreased. The pathophysiological mechanisms leading to these changes and the possible role of toxic agents (i.e., cadmium) are discussed.