"........tobacco is the only legally available consumer product which kills people when it is entirely used as intended....." The Oxford Medical Companion 1994 

Pregnancy 

You already know that smoking when you're pregnant isn't good, but stopping is never easy. 

The following links will help you make a start......

20 Reasons  20 great reasons not to smoke when you are pregnant
Fact or Fiction? The answers to your smoking during pregnancy questions
Reasons for Staying Stopped  Tips and hints on how to stay stopped once the baby is born
Coping with Cravings & Setbacks Cravings only last a few minutes - learn how to cope with them