Smoking has long been recognized as a leading contributor to death and disease worldwide. Despite the known harmful health effects of smoking, however, the March of Dimes reports that at least 10 percent of pregnant women in the United States continue to smoke during pregnancy. Numerous studies have documented the negative consequences of smoking during pregnancy, which the Centers for Disease Control and Prevention, or CDC, describes as the single most preventable cause of death and illness in mothers and their infants.
Premature Rupture of Membranes
The CDC reports that smoking results in a two-fold increase in the risk of premature rupture of membranes, which occurs when the amniotic sac holding the baby breaks before the onset of labor. If this happens prior to the 37th week of pregnancy, it can lead to the delivery of a premature infant.
Placental Abnormalities
According to the CDC, smoking during pregnancy doubles the risks of placental abruption and placenta previa in pregnant women.
Placental abruption is defined as the separation of the placenta from the wall of the uterus before delivery, while placenta previa describes a condition wherein the placenta attaches to the lower part of the uterine wall, partially or totally covering the opening of the uterus. Both can result in heavy bleeding before or during delivery, seriously endangering the life of both mother and baby.
Low Birth Weight
Smoking during pregnancy affects the delivery of oxygen to the unborn baby, which can result in impaired fetal growth. According to the March of Dimes, smoking doubles the risk of delivering a baby with low birth weight, defined as less than 5.5 lbs. or 2,500g.
Exposure of a nonsmoking pregnant woman to secondhand smoke also increases the risk of delivering a baby with low birth weight.
Premature Delivery
Smoking increases the risk of premature delivery, or birth before the 37th week of pregnancy. Low birth weight and prematurity both increase the risk of illness and death in the baby after delivery.
Other Effects of Smoking
Other significant effects associated with smoking include up to a three-fold increase in risk of sudden infant death syndrome, as reported by the CDC, and an increased probability of asthma in infants and young children, as stated by the American Lung Association. Symptoms of nicotine withdrawal can also manifest in the baby, making a newborn jittery and difficult to pacify.
Maternal smoking may also increase the risk of a miscarriage, or loss of the baby before the 20th week of pregnancy. The risk of a stillbirth, defined as fetal death after the 20th week of pregnancy, may likewise increase.
