The results are somewhat surprising. Children born of smoking mothers have lower infant mortality and higher birth weights than those of non-smoking mothers. Hormesis?
Here is the paradox then: Mother’s smoking is believed to reduce the health of the infant, but infant mortality among babies from smoking mothers is much lower than it is in the general population. This is not an isolated finding, but one that has been observed and confirmed on various occasions, and has led even behemoths in the field of statistics (like R.A. Fisher), to conclude that smoking during pregnancy may indeed have beneficial effects for babies; at least for those with low birth-weight, who are exactly those at a greater risk of death.