The mother and her baby are connected by the umbilical cord which is a path way of supply of anything from the mother to the unborn baby so any thing a mother has passes to the baby.
The correct order is Ovulation, Fertilization. Implantation, Development of the embryo and then fetus, then birth, there is dilatation of the cervix followed by birth. After birth the umbilical cord is cut then there is expulsion of the placenta.
It causes breathing problems, cancers, organ damage, changes your appearance for the worst, it smells bad, some of your friends may not want to be around you as much if they can't stand the smoke (like asthmatics), it can kill you, leaves a bad taste in your mouth, it costs a lot of money long term, and it is an addiction that is very hard to get rid of. The worst part is that you can also injure those around you in the same way with secondhand smoking.
The choice to use and continue to use a tobacco product depends on many thing, from personal ones such as self-image to social ones.