Pregnancy and smoking, harmful to smoke during pregnancy?, How smoking harms the unborn baby

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Pregnancy and smoking

Pregnancy is about creating a new life, but ultimately it is the mother’s decision whether or not to continue smoking. Your pregnancy can be a powerful motivation to give up smoking, because you’re making this choice on behalf of your unborn child who is completely dependent on you.
Pre-pregnancy

Smoking makes it harder to conceive, irrespective of which partner smokes.

Both female and male smokers have lower fertility levels, while adults who were born to mothers who smoked have less chance of becoming a parent themselves. Smoking also reduces the chances of IVF succeeding.

It’s thought nicotine reduces a woman’s fertility by affecting the production of hormones that are necessary for pregnancy. Smoking also impedes the transportation of the egg through the Fallopian tubes to the womb.

Male smokers tend to have a sperm count that is 15 per cent lower than that of non-smokers. Smoking can also:

* reduce the amount of semen
* harm the motility of sperm, ie their ability to move around
* affect their shape.

Smoking can also affect the blood vessels that supply the penis, causing erection problems.

If you’re trying for a baby, all of the above could impair fertility.

Quitting smoking will increase your ability to conceive and your likelihood of success with IVF.
Why is it harmful to smoke during pregnancy?

A baby in the womb gets everything from its mother. Nutrients and oxygen come via the placenta and umbilical cord. Smoking not only exposes the foetus to toxins in tobacco smoke, but it also damages placental function.

When a person smokes, some of the oxygen in their blood is replaced by carbon monoxide. If a pregnant woman smokes, her blood and therefore her child’s blood will contain less oxygen than normal. This can cause the foetal heart rate to rise as baby struggles to get enough oxygen.

The particles in tobacco smoke contain different toxic substances that change the blood’s ability to work in a healthy and normal manner. This can affect the placenta that feeds the baby.
How smoking harms the unborn baby

Babies born to mothers who smoke:

* are more likely to be born prematurely and with a low birth weight (below 2.5kg or 5lb 8oz).
* have a birth weight on average 200g (7oz) less than those born to non-smokers. This effect increases proportionally – the more the mother smokes, the less the child weighs.
* have organs that are smaller on average than babies born to non-smokers.
* have poorer lung function.
* are twice as likely to die from cot death. There seems to be a direct link between cot death and parents smoking.
* are ill more frequently. Babies born to women who smoked 15 cigarettes or more a day during pregnancy are taken into hospital twice as often during the first eight months of life.
* get painful diseases such as inflammation of the middle ear and asthmatic bronchitis more frequently in early childhood.
* are more likely to become smokers themselves in later years.

In addition, pregnant women who smoke increase their risk of early miscarriage.

In later pregnancy, smoking mothers are at increased risk of the baby’s placenta coming away from the womb before the baby is born (placental abruption). This may cause the baby to be born prematurely, starve of oxygen, or even to die in the womb (stillborn).
I’m pregnant and still smoking

It is never too late to stop smoking. Every cigarette you decide not to smoke will help your and baby’s health.

Much of the damage caused by smoking can be reversed because your body is a living organism that has the ability to heal itself.

Women who stopped smoking at the halfway point in their pregnancy gave birth to babies with the same average weight as women who had not smoked at all during pregnancy.

You may be tempted just to cut down, but many smokers find they inhale more deeply when smoking fewer cigarettes. So though the number of cigarettes decreases, the intake of damaging substances doesn’t because residues are concentrated towards the butt.

Other studies show that even moderate cigarette smoking is damaging to the foetus, making quitting the most important thing you can do to improve your and baby’s health.
How to stop smoking

You can get support and advice about stopping smoking from your midwife, antenatal clinic or GP. Evidence shows that counselling by qualified health professionals can double quit rates for pregnant women.

Nicotine replacement therapy (NRT) should not ideally be used by pregnant women as an aid to stopping smoking. But for the heaviest smokers who are unable to give up using willpower alone, NRT will deliver less nicotine than cigarettes and none of the other disease-causing agents, eg tar.

You should only use NRT while pregnant after carefully discussing all the risks and benefits with your doctor.

All infos

Smoking During Pregnancy
Smoking is a major public health problem. All smokers face an increased risk of lung cancer, other lung diseases, and cardiovascular and other disorders. Smoking during pregnancy can harm the health of both a woman and her unborn baby. Currently, at least 10 percent of women in the United States smoke during pregnancy (1).

In the United States and in other industrialized countries, 18 percent of women smoke (2). This proportion is somewhat smaller in developing countries where only 8 percent of women smoke (3). Statistics from the United States are compelling. According to the U.S. Public Health Service (4), if all pregnant women in this country stopped smoking, there would be an estimated:
11 percent reduction in stillbirths
5 percent reduction in newborn deaths
Cigarette smoke contains more than 2,500 chemicals. It is not known for certain which of these chemicals are harmful to the developing baby, but both nicotine and carbon monoxide play a role in causing adverse pregnancy outcomes.
How can smoking harm the newborn?
Smoking nearly doubles a woman’s risk of having a low-birthweight baby. In 2004, 11.9 percent of babies born to smokers in the United States were of low birthweight (less than 5½ pounds), compared to 7.2 percent of babies of nonsmokers (1). Low birthweight can result from poor growth before birth, preterm delivery or a combination of both. Smoking has long been known to slow fetal growth. Smoking also increases the risk of preterm delivery (before 37 weeks of gestation) (5). Premature and low-birthweight babies face an increased risk of serious health problems during the newborn period, chronic lifelong disabilities (such as cerebral palsy, mental retardation and learning problems), and even death.

The more a pregnant woman smokes, the greater her risk of having a low-birthweight baby. However, if a woman stops smoking even by the end of her second trimester of pregnancy, she is no more likely to have a low-birthweight baby than a woman who never smoked (6).

A recent study suggests that women who smoke anytime during the month before pregnancy to the end of the first trimester are more likely to have a baby with birth defects, particularly congenital heart defects (7). The risk of heart defects appears to increase with the number of cigarettes a woman smokes.

Can smoking cause pregnancy complications?
Smoking is associated with a number of pregnancy complications. Smoking cigarettes doubles a woman’s risk of developing placental problems (4). These include:

Placenta previa (a low-lying placenta that covers part or all of the opening of the uterus)
Placental abruption (in which the placenta peels away, partially or almost completely, from the uterine wall before delivery)
Both can result in heavy bleeding during delivery that can endanger mother and baby, although cesarean delivery can prevent most deaths.

Smoking in pregnancy increases a woman’s risk of premature rupture of the membranes (PROM), when the sac that holds the baby inside the uterus breaks before completion of 37 weeks of pregnancy (4). (Usually, when it breaks, normal labor ensues within a few hours.) If the rupture occurs before 37 weeks of pregnancy, it often results in the birth of a premature baby.

Does smoking affect fertility?
Cigarette smoking can cause reproductive problems before a woman even becomes pregnant. Studies show that women who smoke may have more trouble conceiving than nonsmokers (4). Studies suggest that fertility returns to normal after a woman stops smoking.

Does smoking during pregnancy cause other problems in babies or young children?
A 2003 study suggests that babies of mothers who smoke during pregnancy undergo withdrawal-like symptoms similar to those seen in babies of mothers who use some illicit drugs (8). For example, babies of smokers appear to be more jittery and difficult to soothe than babies of nonsmokers.

Babies whose mothers smoked during pregnancy are up to three times as likely to die from sudden infant death syndrome (SIDS) as babies of nonsmokers (5).

Can exposure to secondhand smoke during pregnancy harm the baby?
Studies suggest that babies of women who are regularly exposed to secondhand smoke during pregnancy may have reduced growth and may be more likely to be born with low birthweight (5). Pregnant women should avoid exposure to other people’s smoke.

How can a woman stop smoking?
The March of Dimes recommends that women stop smoking before they become pregnant and do not smoke throughout pregnancy and after the baby is born. A woman’s health care provider can refer her to a smoking-cessation program or suggest other ways to help her quit. The March of Dimes supports a 5- to 15-minute, 5-step counseling approach called “The 5 A’s,” which is performed by the health care provider during routine prenatal visits. This approach has been shown to improve smoking cessation rates among pregnant women by at least 30 percent (9).

Studies suggest that certain factors make it more likely that a woman will be successful in her efforts to quit smoking during pregnancy. These include:

Attempting to quit in the past
Having a partner who doesn’t smoke
Getting support from family or other important people in her life
Understanding the harmful effects of smoking
How does exposure to smoke after birth affect a baby?
It is important to stay smoke-free after the baby is born. Parents should refrain from smoking in the home and should ask visitors to do the same. Babies who are exposed to smoke suffer from more lower-respiratory illnesses (such as bronchitis and pneumonia) and ear infections than do other babies. Babies who are exposed to their parents’ smoke after birth also may face an increased risk of asthma and SIDS.

Smoking harms a mother’s health, too. Smokers have an increased risk of lung and other cancers, heart disease, stroke and emphysema (a potentially disabling and, sometimes, deadly lung condition). Quitting smoking makes parents healthier and better role models for their children.

Does the March of Dimes fund research on the risks of smoking during pregnancy?
The March of Dimes has long supported research on the risks of smoking during pregnancy. In the 1970s, March of Dimes-supported research suggested that nicotine and carbon monoxide reduce the supply of oxygen to the baby, perhaps explaining how these chemicals in cigarette smoke reduce fetal growth.

In 2002, a March of Dimes grantee published a study that may shed light on why some women who smoke cigarettes during pregnancy have low-birthweight babies and others do not (10). The researcher reported that pregnant women who smoke are more likely to have a premature or low-birthweight baby if they have either of two common genetic traits (which influence the body’s ability to dispose of certain chemicals). These findings could lead to better ways to identify and treat women at high risk of having a low-birthweight baby.

A current March of Dimes grantee is investigating whether smoking at a critical stage of embryonic palate development increases the risk of cleft lip/palate.

What resources are available for pregnant women?

American Legacy Foundation
www.smokefree.gov/
1800quitnow.cancer.gov/
A toll-free quit line (800)-QUITNOW (784-8669)
What resources are available for health care providers?
The American College of Obstetricians and Gynecologists provides information for health care providers to assist them as they help patients stop smoking.
Smoking Cessation for Pregnancy and Beyond is a free CME course for health care providers available from Dartmouth Medical School.

References
Martin, J.A., et al. Births: Final Data for 2004. National Vital Statistics Reports, volume 55, number 1, September 29, 2006.
Centers for Disease Control and Prevention (CDC). Smoking and Tobacco Fact Sheet: Women and Smoking. February 28, 2007.
World Health Organization (WHO). Women and the Tobacco Epidemic: Challenges for the 21st Century. 2001.
U.S. Department of Health and Human Services. The Health Consequences of Smoking: A Report of the Surgeon General, 2004. Centers for Disease Control and Prevention, Office on Smoking and Health, Atlanta Georgia, May 2004.
Centers for Disease Control and Prevention (CDC). What Do We Know About Tobacco Use and Pregnancy. June 11, 2007.
American College of Obstetricians and Gynecologists (ACOG). Smoking Cessation during Pregnancy. ACOG Committee Opinion, number 316, October 2005.
Malik, S., et al. Maternal Smoking and Congenital Heart Defects. Pediatrics, volume 121, number 4, April 2008, pages e810-e816.
Law, K.L., et al. Smoking During Pregnancy and Newborn Neurobehavior. Pediatrics, volume 111, number 6, June 2003, pages 1318-1323.
Centers for Disease Control and Prevention (CDC). Preventing Smoking During Pregnancy. November 2005.
Wang, X., et al. Maternal Cigarette Smoking, Metabolic Gene Polymorphism, and Infant Birth Weight. Journal of the American Medical Association, volume 287, number 2, January 9, 2002, pages 195-202.