Autrefois constituйes uniquement de papier et de tabac, les cigarettes ont depuis les annйes 60 de plus en plus d ajouts divers et variйs. Au total plus de 4 000 substances chimiques inhalйes par la fumйe de cigarettes, dont plus de 60 classйes cancйrigиnes par le Comitй International de Recherche sur le Cancer.
Un professeur de chimie de l’Ecole de Mйdecine de Paris du nom de Louis Nicolas Vauquelin, dйcouvrit en 1909, un principe actif azotй dans les feuilles de tabac. Grвce а ses recherches, la nicotine fut dйcelйe quelques annйes plus tard dans le tabac. On sait aujourd hui qu elle reprйsente environ 5% du poids de la plante et que le tabac est la seule plante….
La cigarette est le principal dйbouchй du tabac brut. Elle reprйsente 90% des utilisations mondiales. Et pourtant elle ne fut que rйcemment inventйe, vers 1850, et ne devint produit de consommation courante qu au XXe siиcle. Dйfinie comme une petit boudin de tabac hachй entourй d une feuille de papier fin , la cigarette n en suit pourtant pas moins un…
How smoking during pregnancy affects you and your baby
Ob gyn Robert Welch has helped thousands of women with high risk pregnancies realize their dreams of a healthy baby. But even after all those successes, there’s still one situation that truly scares him a pregnant woman who can’t quit smoking.
“Smoking cigarettes is probably the No. 1 cause of adverse outcomes for babies,” says Welch, who’s the chairman of the Department of Obstetrics and Gynecology at Providence Hospital in Southfield, Michigan. He’s seen the complications far too many times babies born prematurely, babies born too small, babies who die before they can be born at all. In his view, pregnancies would be safer and babies would be healthier if pregnant smokers could somehow swap their habit for a serious disease such as diabetes or high blood pressure.
“I can control those conditions with medications,” Welch says. But when a pregnant woman smokes, he says, nothing can protect her baby from danger.
Why is it so dangerous to smoke during pregnancy?
Cigarette smoke contains more than 4,000 chemicals, including truly nasty things like cyanide, lead, and at least 60 cancer causing compounds. When you smoke during pregnancy, that toxic brew gets into your bloodstream, your baby’s only source of oxygen and nutrients.
While none of those 4,000 plus chemicals is good for your baby (you would never add a dollop of lead and cyanide to his strained peaches), two compounds are especially harmful nicotine and carbon monoxide. These two toxins account for almost every smoking related complication in pregnancy, says ob gyn James Christmas, director of Maternal Fetal Medicine for Commonwealth Perinatal Associates at Henrico Doctors’ Hospital in Richmond, Virginia.
The most serious complications including stillbirth, premature delivery, and low birth weight can be chalked up to the fact that nicotine and carbon monoxide work together to reduce your baby’s supply of oxygen. Nicotine chokes off oxygen by narrowing blood vessels throughout your body, including the ones in the umbilical cord. It’s a little like forcing your baby to breathe through a narrow straw. To make matters worse, the red blood cells that carry oxygen start to pick up molecules of carbon monoxide instead. Suddenly, that narrow straw doesn’t even hold as much oxygen as it should.
How will smoking affect my baby?
A shortage of oxygen can have devastating effects on your baby’s growth and development. On average, smoking during pregnancy doubles the chances that a baby will be born too early or weigh less than 5 1/2 pounds at birth. Smoking also more than doubles the risk of stillbirth.
Every cigarette you smoke increases the risks to your pregnancy. A few cigarettes a day are safer than a whole pack, but the difference isn’t as great as you might think. A smoker’s body is especially sensitive to the first doses of nicotine each day, and even just one or two cigarettes will significantly tighten blood vessels. That’s why even a “light” habit can have an outsize effect on your baby’s health.
How smoking affects your baby
Weight and size
On average, a pack a day habit during pregnancy will shave about a half pound from a baby’s birth weight. Smoking two packs a day throughout your pregnancy could make your baby a full pound or more lighter. While some women may welcome the prospect of delivering a smaller baby, stunting a baby’s growth in the womb can have negative consequences that last a lifetime.
Body and lungs
Undersize babies tend to have underdeveloped bodies. Their lungs may not be ready to work on their own, which means they may spend their first days or weeks attached to a respirator. After they’re breathing on their own (or even if they did from the start), these babies may have continuing breathing problems because of delayed lung development or other adverse effects of nicotine. Children whose mothers smoked during pregnancy are especially vulnerable to asthma, and have double or even triple the risk of sudden infant death syndrome (SIDS).
Babies whose mother smoked in the first trimester of pregnancy are more likely to have a heart defect at birth.
In a U.S. Centers for Disease Control and Prevention (CDC) study published in February 2011, these babies’ risk of having certain types of congenital heart defects was 20 to 70 percent higher than it was for babies whose moms didn’t smoke. The defects included those that obstruct the flow of blood from the right side of the heart into the lungs (right ventricular outflow tract obstructions) and openings between the upper chambers of the heart (atrial septal defects).
Researchers analyzed data on 2,525 babies who had heart defects at birth and 3,435 healthy babies born in Baltimore and Washington, D.C., between 1981 and 1989.
Smoking during pregnancy can have lifelong effects on your baby’s brain. Children of pregnant smokers are especially likely to have learning disorders, behavioral problems, and relatively low IQs.