|
Environmental Risks and Pregnancy
There are more than 4 million chemical mixtures in homes and businesses in this country, with little information on the effects of most of them during pregnancy. However, a few are known to be harmful to an unborn baby. Most of these are found in the workplace, but certain environmental pollutants found in air and water, as well as chemicals used at home, may pose a risk during pregnancy.
A pregnant woman can inhale these chemicals, ingest them in food or drink, or, in some cases, absorb them through the skin. For most hazardous substances, a pregnant woman would have to be exposed to a large amount for a long time in order for them to harm her baby. Most workplaces have preventive measures to help make sure this doesn’t happen. Pregnant women can take steps to help protect themselves and their babies from pollutants and potentially risky chemicals used at home.
Stress and Prematurity
Pregnancy is a special time for a woman and her family. It is a time of many changes: in a pregnant woman’s body, in her emotions and in the life of her family. As welcome as they may be, these changes often add new stresses to the lives of busy pregnant women who already face many demands at home and at work.
Too much stress can be uncomfortable for anyone. In the short term, a high level of stress can cause fatigue, sleeplessness, anxiety, poor appetite or overeating, headaches and backaches. When a high level of stress continues for a long period, it may contribute to potentially serious health problems, such as lowered resistance to infectious diseases, high blood pressure and heart disease.
Pregnant women who experience high levels of stress also may be at increased risk of premature delivery (1). Babies born before 37 completed weeks of pregnancy are considered premature. Babies born too small and too soon are at increased risk for health problems during the newborn period, lasting disabilities (such as mental retardation and cerebral palsy), and even death.
Most women cope well with the emotional and physical changes of pregnancy and other stresses in their lives. A pregnant woman who feels she is coping well with stress taking good care of herself, feeling energized rather than drained, and functioning well at home and work) probably does not face health risks from stress.
Pregnant women who are concerned about the level of stress in their lives, and their ability to cope with it, should talk with their health care provider. A health care provider can refer a woman to resources in her community and help her take steps to reduce and cope with stress.
What types of stress may contribute to premature delivery?
The routine everyday stresses that we all face, such as work deadlines and traffic delays, probably don’t contribute much to premature birth. It’s important to keep in mind that stress is not all bad. When managed properly, a little stress can provide us with the drive to meet new challenges.
But certain types of severe or long-lasting stress may pose a risk in pregnancy. Some studies suggest that women who experience negative life events, such as divorce, death in the family, serious illness or loss of a job, may be at increased risk of premature delivery (1). It is important to remember that while these sorts of stress may increase the risk of a premature birth, most women who experience these sorts of stress do not deliver prematurely.
Women who experience a catastrophic event during pregnancy may be at increased risk for premature delivery. One study found that pregnant women who worked within two miles of the World Trade Center on September 11, 2001, had significantly shorter gestations than women who worked farther from the site (1). Another study found that pregnant women who experienced a major earthquake had shorter gestations (1).
The timing of the event may also influence pregnancy outcome. Studies suggest that women who experienced the World Trade Center attack or an earthquake in the first trimester of pregnancy tended to deliver earlier than women who experienced these catastrophic events later in pregnancy (1).
Chronic stress may play a role in premature delivery. For example, studies suggest that women who are homeless or have serious financial problems may be more likely to deliver prematurely (1). Working outside the home has not been linked to premature birth in most studies. However, women who find their jobs especially physically or emotionally stressful may face some risk (1).
Smoking During Pregnancy
In the United States more than 20 percent of women smoke. According to the World Health Organization, a similar number of women in other developed countries smoke, and about 9 percent of women in developing countries smoke. Many of these women smoke while they are pregnant. This is a major public health problem because, not only can smoking harm a woman’s health, but smoking during pregnancy can lead to pregnancy complications and serious health problems in newborns.
Statistics from the United States are compelling. If all pregnant women in the United States stopped smoking, there would be an estimated 11 percent reduction in stillbirthsand a 5 percent reduction in newborn deaths, according to the U.S. Public Health Service.1 Currently, at least 11 percent of women in the United States smoke during pregnancy.2
Cigarette smoke contains more than 2,500 chemicals. It is not known for certain which of these chemicals are harmful to a developing baby. However, both nicotine and carbon monoxide are believed to 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 2002, 12.2 percent of babies born to smokers in the United States were of low birthweight (less than 5½ pounds), compared to 7.5 percent of babies of nonsmokers.2 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. Studies also suggest that smoking increases the risk of preterm delivery37 weeks of gestation). 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 the risk to her baby. However, if a woman stops smoking by the end of her first trimester of pregnancy, she is no more likely to have a low-birthweight baby than a woman who never smoked. Even if a woman has not been able to stop smoking in her first or second trimester, stopping during the third trimester can still improve her baby’s growth.
Drinking Alcohol During Pregnancy
Drinking alcohol during pregnancy can cause physical and mental birth defects. Each year, up to 40,000 babies are born with some degree of alcohol-related damage (1, 2). Although many women are aware that heavy drinking during pregnancy can cause birth defects, many do not realize that moderate—or even light—drinking also may harm the fetus.
In fact, no level of alcohol use during pregnancy has been proven safe. Therefore, the March of Dimes recommends that pregnant women do not drink any alcohol—including beer, wine, wine coolers and hard liquor—throughout their pregnancy and while nursing. In addition, because women often do not know they are pregnant for a few months, women who may be pregnant or those who are attempting to become pregnant should abstain from drinking alcoholic beverages.
Recent government surveys indicate that about 13 percent of pregnant women drink during pregnancy (3). About 3 percent of pregnant women report binge drinking (five or more drinks on any one occasion) or frequent drinking (seven or more drinks per week) (3). Women who binge drink or drink frequently greatly increase the risk of alcohol-related damage to their babies.
When a pregnant woman drinks, alcohol passes swiftly through the placenta to her fetus. In the unborn baby's immature body, alcohol is broken down much more slowly than in an adult's body. As a result, the alcohol level of the baby's blood can be even higher and can remain elevated longer than the level in the mother's blood. This sometimes causes the baby to suffer lifelong damage.
What are the hazards of drinking alcohol during pregnancy?
Drinking alcohol during pregnancy can cause a number of birth defects, ranging from mild to severe. These include mental retardation; learning, emotional and behavioral problems; and defects involving the heart, face and other organs. The term "fetal alcohol spectrum disorder" is used to describe the many problems associated with exposure to alcohol before birth. The most severe of these is fetal alcohol syndrome (FAS), a combination of physical and mental birth defects.
Consuming alcohol during pregnancy also increases the risk of miscarriage, low birthweight(less than 5 1/2 pounds) and stillbirth. A 2002 Danish study found that women who drank five or more drinks a week were three times more likely to have a stillborn baby than women who had less than one drink a week (4).
What is fetal alcohol syndrome (FAS)?
FAS is one of the most common known causes of mental retardation, and the only cause that is entirely preventable. Studies by the Centers for Disease Control and Prevention (CDC) suggest that between 1,000 and 6,000 babies in the United States are born yearly with FAS (3).
Babies with FAS are abnormally small at birth and usually do not catch up on growth as they get older. They have characteristic facial features, including small eyes, a thin upper lip and smooth skin in place of the normal groove between the nose and upper lip. Their organs, especially the heart, may not form properly. Many babies with FAS also have a brain that is small and abnormally formed, and most have some degree of mental disability. Many have poor coordination, a short attention span and emotional and behavioral problems.
The effects of FAS last a lifetime. Even if not mentally retarded, adolescents and adults with FAS have varying degrees of psychological and behavioral problems and often find it difficult to hold down a job and live independently (3)
What are fetal alcohol effects (FAE)?
The CDC estimates that about three times the number of babies born with FAS are born with lesser degrees of alcohol-related damage (5). This condition is sometimes referred to as fetal alcohol effects (FAE). These children have some of the physical or mental birth defects associated with FAS. The Institute of Medicine uses more specific diagnostic categories for FAE, referring to the physical birth defects (such as heart defects) as alcohol-related birth defects (ARBD), and to the mental and behavioral abnormalities as alcohol-related neurodevelopmental disorders (ARND) (6).
In general, alcohol-related birth defects (such as heart and facial defects) are more likely to result from drinking during the first trimester. Drinking at any stage of pregnancy can affect the brain as well as growth (5).
During pregnancy, how much alcohol is too much?
No level of drinking alcohol has been proven safe during pregnancy. The full pattern of FAS usually occurs in offspring of women who are alcoholics or chronic alcohol abusers. These women either drink heavily (about four or five or more drinks daily) throughout pregnancy or have repeated episodes of binge drinking. However, FAS can occur in women who drink less. ARBD and ARND can occur in babies of women who drink moderately or lightly during pregnancy.
Researchers are taking a closer look at the more subtle effects of moderate and light drinking during pregnancy. A 2002 study found that 14-year-old children whose mothers drank as little as one drink a week were significantly shorter and leaner and had a smaller head circumference (a possible indicator of brain size) than children of women who did not drink at all (7). A 2001 study found that 6- and 7-year-old children of mothers who had as little as one drink a week during pregnancy were more likely than children of non-drinkers to have behavior problems, such as aggressive and delinquent behaviors. These researchers found that children whose mothers drank any alcohol during pregnancy were more than three times as likely as unexposed children to demonstrate delinquent behaviors (8).
Other researchers report behavioral and learning problems in children exposed to moderate drinking during pregnancy, including attention and memory problems, hyperactivity, impulsivity, poor social and communication skills, psychiatric problems (including mood disorders) and alcohol and drug use (1).
Is there a cure for FAS?
There is no cure for FAS. However, a recent study found that early diagnosis (before 6 years of age) and being raised in a stable, nurturing environment can improve the long-term outlook for individuals with FAS (9). Those who experienced these protective factors during their school years were two to four times more likely to avoid serious behavioral problems resulting in trouble with the law or confinement in a psychiatric institution.
References
1. Sokol, R.J., et al. Fetal Alcohol Spectrum Disorder. Journal of the American Medical Association, volume 290, number 22, December 10, 2003, pages 2996-2999.
2. National Organization on Fetal Alcohol Syndrome. Frequently Asked Questions: What are the Statistics and Facts about FAS and FASD? Accessed 8/17/04.
3. Bertrand, J., et al., National Task Force on FAS/FAE. Fetal Alcohol Syndrome: Guidelines for Referral and Diagnosis. Atlanta, GA: Centers for Disease Control and Prevention, July 2004.
4. Kesmodel, U., et al. Moderate Alcohol Intake During Pregnancy and the Risk of Stillbirth and Death in the First Year of Life. American Journal of Epidemiology, volume 155, number 4, February 15, 2002, pages 305-312.
5. Centers for Disease Control and Prevention. Frequently Asked Questions: Fetal Alcohol Syndrome. Updated 8/5/04, accessed 8/17/04.
6. Institute of Medicine. Fetal Alcohol Syndrome: Diagnosis, Epidemiology, Prevention, and Treatment. Washington, D.C., National Academy Press, 1996.
7. Day, N.L., et al. Prenatal Alcohol Exposure Predicts Continued Deficits in Offspring Size at 14 Years of Age. Alcoholism: Clinical and Experimental Research, volume 26, number 10, 2002, pages 1584-1591.
8. Sood, B., et al. Prenatal Alcohol Exposure and Childhood Behavior at Age 6 to 7. Pediatrics, volume 108, number 2, August 2001, e34.
9. Streissguth, A.P., et al. Risk Factors for Adverse Life Outcomes in Fetal Alcohol Syndrome and Fetal Alcohol Effects. Journal of Developmental and Behavioral Pediatrics, volume 25, number 4, August 2004, pages 228-238.
10. Little, R.E., et al. Maternal Alcohol Use During Breast-Feeding and Infant Mental and Motor Development at One Year. New England Journal of Medicine, volume 321, number 7, August 17, 1989, pages 425-430.
11. Meek, J.Y. American Academy of Pediatrics: New Mother's Guide to Breastfeeding. New York, NY: Bantam Books and the American Academy of Pediatrics.
09-404-00 1/05
© 2007 March of Dimes Foundation. All rights reserved.
|
