Smoking tobacco puts toxic chemicals into your lungs and blood stream and, therefore, into your unborn child as well. Many studies worldwide document babies born prematurely as a result of the mother's inability to stop smoking and the child's inability to develop normally. As a result, the American Lung Association warns, when you smoke you risk premature delivery, birth of an underdeveloped baby or even stillbirth.
Preterm Smoking Toxicity
Cigarette smoke introduces nicotine and carbon monoxide into your lungs, your blood and your fetus. These are commonly understood to be harmful. But a 2009 report published in the journal "Reproductive Toxicology," by Dr. J. M. Rogers documented over 4,000 chemicals in cigarette smoke, including toxic heavy metals. Many of the chemicals are known carcinogens. Rogers warns that smoking causes preterm births of babies who suffer disorders which potentially threaten life-long consequences for the surviving children. Some preterm births caused by tobacco are stillborn.
Preterm Complications
An Australian study published in 2001 from Adelaide University-Women's and Children's Hospital found that heavy smoking, usually defined as 10 or more cigarettes per day, increased the risk of preterm birth. A 2005 report published in the "British Journal of Obstetrics and Gynecology" by researchers from Aarhus University Hospital in Denmark, documented a 40 percent increased risk of preterm births in smoking mothers as compared to non-smokers. Preterm is generally defined as before 37 weeks of gestation and very-preterm as before 32 weeks. A 2005 report of research carried out at the Karolinska Institute in Stockholm, Sweden, indicated that smoking mothers had an increased incidence of very-preterm delivery and a higher probability of preterm membrane rupture and third trimester bleeding. MayoClinic.com reports that preterm labor is more common in smoking mothers. It does not always result in a preterm birth but does increase risks to mothers and babies.
Low Birth Weight
The Australian study documented that the likelihood of preterm births is dose-related. The more cigarettes smoked per day, the higher the probability. This prematurity translates to low birth weight babies at delivery. However, the babies were also statistically small for gestational age indicating that smoking retards intrauterine development. A 2007 report published by the U.S. Centers for Disease Control and Prevention states that preterm babies of smoking mothers average only 5.5 lbs., about 1/2 lb. below average for nonsmoking mothers.
Stillbirths
The U.S. Centers for Disease Control and Prevention report, and many other U.S. researchers, also note that smoking mothers accounted for a higher incidence of stillbirths as well as preterm births. Their surviving babies also suffered a risk of 1.4 to 3.0 times the national average for sudden infant death syndrome or SIDS.
Cessation
The U.S. experience reported by the Centers for Disease Control and Prevention in 2007 documented that 21 percent of pregnant women smoke more than 10 cigarettes per day, qualifying as heavy smokers. Almost half of pre-pregnancy smokers quit during pregnancy and about half of those remained non-smokers six months post-delivery. Higher-education levels correlated with lower smoking incidence. The Australian study revealed that the highest incidence of both smoking and preterm births occurred among aboriginal women. This population also suffers higher rates of poor nutrition and health and lower educational achievement. The physicians conducting this study and those reporting for the CDC in the United States strongly advise intense, socially relevant anti-smoking education.
The U.S. Centers for Disease Control and Prevention urges pregnant women who want to stop smoking to consult their physician and attend smoking cessation clinics. Smokefree.gov offers step-by-step guides and expert consultations. These resources are expected to positively impact the preterm birth rate and all associated infant and maternal health problems.
References
- "Medical Journal of Australia"; The Contribution of Maternal Smoking to Preterm Birth; Chan et al.; 2001
- "BJOG: An International Journal of Obstetrics & Gynaecology"; Smoking During Pregnancy and Preterm Birth; Wisborg et al; 1996
- "Acta Obstetricia et Gynecologica Scandinavica"; Maternal Smoking and Causes of Very Preterm BirthKyrklund-Blomberg et al.; 2005
- "Reproductive Toxicology"; Tobacco and Pregnancy; JM Rogers; 2009
