Another published study, "Smoking Cessation Reduces Postoperative Complications: A Systematic Review and Meta-analysis," examined six randomized trials and 15 observational studies to look at the effects of preoperative smoking cessation on postoperative complications. The findings were: 1) taken together, the studies demonstrated decreased the likelihood of postoperative complications in patients who ceased smoking prior to surgery; 2) overall, each week of cessation prior to surgery increased the magnitude of the effect by 19%. A significant positive effect was noted in trials where smoking cessation occurred at least four weeks prior to surgery; 3) For the six randomized trials, they demonstrated on average a relative risk reduction of 41% for postoperative complications. 
It is recommended that you first try to quit without medication. However, if you are unable to quit, you may use nicotine replacement therapy (gum, lozenges, mouth spray, patches, or an inhalator) to help you. While using these products is considered safer than smoking, even this smaller amount of nicotine may not be entirely risk-free for your baby.
If you are pregnant, it is important to consult your doctor before using nicotine replacement therapy to discuss the risks and benefits of using it. Pregnant women should also seek assistance from the Quitline and its advisors for alternative quitting methods.