Experts don't know exactly which components of smoke have what effects, but we do know that these toxins get into the mother's blood and cross the placenta. In addition, they cause decreased blood flow and reduced oxygen supply to the fetus. Smoking also reduces vitamin C levels, among other vitamin levels. If you smoke during pregnancy, your baby may suffer from growth retardation, mental disorders, placental complications such as abruptio placenta and placenta previa, miscarriage, or even death. You, meanwhile, may experience symptoms ranging from shortness of breath to vaginal bleeding.
Significant effects can occur with less than half a pack of cigarettes daily.
If you or your husband smokes, you may have a harder time becoming pregnant. Male smokers have been found to have lower sperm counts, and in at least one study, odd-shaped sperm. Once you do get pregnant, miscarriages are more common. There is also some evidence that smoking increases the incidence of tubal pregnancy, which can be very dangerous for the mother. A recent 10-year study of nearly 248,000 women by the U.S. Centers for Disease Control in Atlanta confirms that low birth weight is also tied to smoking during pregnancy.