Smoking and pregnancy

I cannot stand to see a pregnant women smoking!! There is a women that works in the hospital I do that is pregnant and you can see her outside at any given moment smoking. A person in the medical profesion smoking while pregnant!!!!
Yes we all know the dangers of smoking, everyone knows it's bad for us, blah blah blah ... we even know the dangers of second hand smoke. So why on earth would someone be so selfish to smoke while carrying a baby??? That poor child has no say in what is going on, the danger it is being put in. The mere 2,500 chemicals being put into that unborn childs system could potentially kill it!!!
Smoking during pregnancy not only increases the risk of having a baby with a low birth rate, but it greatly increases the risk of having a baby pre term (prior to 37 weeks).
Let's talk birth defects, etc ... cleft lip, cleft palate, cerebal palsy, mental retardation, learning difficulties, behavioral problems, asthma, ear infections, and tonsilities. They are TWICE as likely to die from SIDS (Sudden Infant Death Sydrom).

That's all just the tip of the iceburg ... so my quetion is WHY??? Why be so selfish to potentially harm an unborn child???