Smoking and Pregnancy Smoking affects everything about pregnancy, including fertility, conception, the fetus's development, labor, and growth during childhood. So if you're planning to have a baby, the time to quit smoking is now, not after you get pregnant. The main consequence of smoking during pregnancy is that the fetus doesn't grow adequately and is often born with a low birth weight. Studies show that children who are born with low birth weight are on the average shorter, have more respiratory problems and do poorer in school than children whose mothers didn't smoke during pregnancy. If you smoke during pregnancy, you also have a 25 percent greater chance of having a miscarriage, premature birth or a stillbirth.
Cigarette smoking interferes with the blood supply to the fetus.
Several toxins enter the fetus's blood including carbon monoxide, nicotine and cyanide, which affect the fetus's supply of nutrients and oxygen. When you smoke just two cigarrettes in a row, the oxygen you're depriving your baby of causes his heart rate to increase and affects his breathing-like motions. These are both signs of fetal distress. Even breathing smoke from others affects the fetus so to protect your baby, avoid smoky places. For more information on having a healthy baby, talk with your doctor.