Many doctors suggest smoking is worse for you and your baby than serious diseases like diabetes. There is absolutely nothing you can do to protect your baby from smoking besides quitting. Cigarettes have over 4,000 different chemicals that are harmful for your baby, things such as lead and cyanide. By far the two most harmful are nicotine and carbon monoxide. If you smoke a pack a day during pregnancy you will shave a half of a pound off of your baby’s birth weight, and two pack a day shave off one pound on average. The nicotine and carbon monoxide choke off oxygen and blood from your baby making it much harder for your baby to develop. Different birth defects include heart problems, reduced weight, less developed body and lungs, and it increases the rate of stillborn and premature babies. Smoking can also cause learning disabilities and is proven to lower their IQ greatly. Talk to your physician on methods that can help you successfully quit smoking.