Cigarette Smoking

Cigarette smoking can have serious effects on you and your developing baby. Stop smoking before or during pregnancy; fetal and infant mortality rates increase by more than 50% in first-time pregnant women who smoke more than a pack of cigarettes a day.
Tobacco smoke contains harmful substances, including nicotine, carbon monoxide, hydrogen cyanide, tars, resins and some cancercausing agents. When you inhale cigarette smoke, it crosses the placenta to your baby with all the additional substances, which may harm the fetus.
The problem is so serious that warnings for pregnant women appear on every cigarette package:

SURGEON GENERAL'S WARNING: Smoking by pregnant women may result in fetal injury, premature birth and low birthweight.
Effects on the Fetus. A pregnant woman who smokes reduces her fetus's oxygen supply by as much as half because carbon monoxide in cigarette smoke displaces oxygen in the mother's bloodstream. Toxins in cigarette smoke narrow blood vessels. Smoking can damage the placenta and hinder the baby's growth.

Infants born to mothers who smoke weigh less than other babies, which can cause problems. Increased incidence of reading disorders have been noted in children born to mothers who smoked during pregnancy. Hyperactivity (minimal-brain-dysfunction syndrome) is also more common in children born to women who smoke.

If a woman smokes during pregnancy, the substances she inhales interfere with her body's absorption of vitamins Band C and folic acid, and increase her risk of pregnancy-related complications. Smoking has been associated with specific birth defects, including cleft palate, heart defects and neural-tube defects, such as spina bifida.

Effects on the Pregnant Woman. Serious pregnancy complications are more common among women who smoke than among women who don't. The risk of developing placental abruption increases by 25% in moderate smokers and 65% in heavy smokers. Placenta previa occurs 25% more often in moderate smokers and 90% more often in heavy smokers. (For further information on these problems, see pages 265 and 266.) Cigarette smoking increases the risk of miscarriage, premature rupture of membranes and fetal death or death of a baby soon after birth. Risk is directly related to the number of cigarettes a woman smokes each day. Risk can be even greater if you smoke more than a pack of cigarettes a day.

The best thing to do is quit smoking completely before and during pregnancy. If you can't quit totally, reduce the number of cigarettes you smoke to help reduce your risks.
Effects of Secondary Smoke. Exposure to secondary smoke increases a nonsmoker's risk of giving birth to a low-birth-weight baby. Researchers have found significant levels of nicotine in the hair of newborns exposed to passive smoke for at least 3 hours a day during pregnancy. Ask your husband, family members, friends and coworkers to stop smoking around you while you're pregnant. Avoid situations that expose you to secondary smoke!