The idea of just quitting to get pregnant or having a baby can pose a risk after the baby is delivered. You can figure now that the risks are now gone, you quit for the important time period. But still keep in mind that even though you did your baby a favor by quitting, you really did yourself the bigger favor.
For not only did you reduce the risk to your baby, you reduced your risk of being sicker throughout your life and eventually dying prematurely--you increased your ability to be active with your baby, throughout his or her life, even when your baby becomes an adult. You increased the odds that you will be around to see your baby eventually have children of his or her own, and even then you can be an active participant in yet another generation, as opposed to an elderly person on oxygen who watches family events from the sidelines, if you can even go to see them at all.
Quitting for pregnancy is a reason to start your quit. Staying off though is more comprehensive than this. There are many other benefits that go along with staying an ex-smoker that will stick with you throughout your entire life. To keep these benefits, always remember that the best way to improve "your" overall health and quality of life is to never take another puff!
Joel