*sighs*
R-E-A-D your article, or at least just the title.
The developing baby cannot feel smoke in the womb.
It is absorbed throught the mother's lungs. Thus any reaction to the noxious chemicals absorbed would be through the umbilical cord or perhaps (to a lesser degree) through the amniotic fluid.
Not sure about when recognizing mother's voice begins, but reaction to sound happens earlier. Music listened to during preganancies are favored after the baby is born, as well as even the type of food the mother eats, among other things.