What Percentage of Babies Are Born With Some Kind of Birth Defect?

Birth Defects

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Photo by: Jaimie Duplass

A birth defect is an abnormality in the torso structure or chemistry of a newborn child. It may be caused past hereditary factors (that is, by genetic causes), by environmental influences that affect the embryo or fetus in the mother'due south womb, or past a combination of factors. Often, the cause of a nativity defect is unknown.

KEYWORDS

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Genetics

Pregnancy

Amniocentesis

Infant bloodshed

Nascency defects sometimes are called congenital anomalies (kon-JEN-i-tal a-NAM-a-leez). Congenital means present at nativity, and anomalies are abnormalities or irregularities. An abnormality present at nascence usually is not considered a nativity defect unless it results in a disease or in a concrete or mental inability. For example, birthmarks are seldom considered nascence defects because they unremarkably do not cause health problems.

The March of Dimes estimates that iii to 5 percent of babies built-in in the U.s.a. accept some type of nascence defect. Some nascency defects, such every bit fissure palate, occur infrequently. Others, such equally some built heart defects, are more common. Some hereditary defects are more mutual in certain populations than in others. For case, sickle-jail cell anemia, an inherited blood affliction, occurs mainly in people of African ancestry, whereas Tay-Sachs illness, a fatal disorder of body chemical science, primarily affects people of eastern European Jewish beginnings.

How Do Hereditary Factors Crusade Birth Defects?

Each of us has genes ^* that are inherited from our parents. The genes occur in pairs along threadlike bodies called chromosomes ^* , which are located in the nucleus ^* of each cell in the body. Genes make up one's mind our inborn characteristics, or traits. These traits include how nosotros look and how the chemic substances in our bodies function. In the case of nascence defects, the genes also may determine abnormalities if they are faulty in some fashion.

Mendelian inheritance patterns

The simplest patterns of birth defect inheritance are called Mendelian, named for the Austrian monk Gregor Mendel who observed them in the nineteenth century. In Mendelian inheritance, traits (including defects) can be transmitted by way of ascendant or recessive genes.

It works this way: A child inherits two copies of each gene, one from the mother and one from the male parent. If a defective factor is dominant, a child who inherits even one copy of it will have the defect. That is because the lacking copy "dominates," or overwhelms, the normal copy inherited from the other parent. Simply if a defective gene is recessive, the child would accept to inherit two lacking copies—i from the mother and one from the father—in order to have the defect. A person who inherited but ane defective copy would be healthy but could pass the defective re-create on to his or her own children. These kinds of inheritance patterns cause what researchers call autosomal (aw-to-SO-mal) birth defects.

Examples of autosomal ascendant nascence defects are Huntington's disease, a nervous organisation disorder, and Marfan syndrome, which is characterized past tallness, elongated bones, and heart bug. Some birth defects, such as Huntington'due south disease, may non show symptoms for many years.

Other nascence defects are adamant by genes located on the Ten chromosome (the Ten and Y chromosomes determine the sexual practice of an infant). Such abnormalities are said to be X-linked. Hemophilia, a claret disorder, and color blindness are examples of 10-linked nascency defects.

^* genes are chemicals in the body that help determine a person's characteristics, such every bit pilus or middle colour. They are inherited from a person's parents and are contained in the chromosomes constitute in the cells of the trunk.

^* chromosomes are thread-similar structures inside cells on which the genes are located.

^* nucleus is the part of the cell that contains its genetic information.

Many hereditary nascence defects, however, are not simply dominant, recessive, or X-linked. They may exist produced instead by multiple faulty genes.

Chromosome abnormalities

Some birth defects are caused by extra, missing, incomplete, or misshapen chromosomes. Down syndrome, one of the most mutual nascency defects, usually is caused by the presence of an extra chromosome in the cells. Downwardly syndrome produces mental retardation, short stature, and distinctive facial features. Defects involving the sex activity chromosomes tin can produce problems in sexual development, including sterility, which is an disability to have children.

How Practice Environmental Factors Cause Nativity Defects?

Birth defects also can be acquired by environmental factors, either lone or together with faulty genes. "Environmental" hither refers to the environment in the mother's uterus, or womb, rather than to the globe's surroundings. However, scientists are studying the possible influence on birth defects of poisons in the earth's surround.

Pregnant women who swallow excessive amounts of booze during the early stages of pregnancy risk having babies with fetal booze syndrome. Children with this disorder may have various defects in growth, facial advent, and mental ability. Scientists are studying whether even moderate use of alcohol can damage a fetus. Smoking during pregnancy increases the likelihood that the baby volition have lower than normal weight at birth, increasing the risk of defects.

Some illnesses in a significant adult female can cause damage to the fetus. For example, German measles (rubella) can cause deafness, blindness, and heart defects in the newborn. Sexually transmitted diseases also can be transmitted to the fetus or to the newborn at birth.

Certain medications accept been linked to nascence defects. The most famous is the drug thalidomide (tha-LID-o-mide), a sedative that in the early 1960s was plant to cause greatly shortened artillery and legs in many newborn infants. Many other medications, including tranquilizers and antibacterial and anticancer drugs, can cause congenital abnormalities.

Other environmental factors believed to increase the adventure of birth defects include poor nutrition and the age of the mother. For instance, the older a significant woman is, the more probable she is to give birth to a child with Down syndrome. If the expectant mother is 35 or older, experts recommend that the fetus be tested.

How Practice Doctors Diagnose Birth Defects?

Some birth defects tin be diagnosed while the child is yet in its female parent'south womb. A process chosen ultrasound, which uses sound waves to produce an image of a fetus on a screen, tin detect some malformations. For example, a defect called spina bifida, in which a part of the spinal cord is exposed, tin can be discovered by ultrasound.

The U.S. and the World

• An estimated 515,000 people worldwide died of birth defects in 1998. Almost 93 percent of those deaths were in low-and center-income nations.
• More than 28 million people worldwide live with birth defects, and about 93 percent alive in countries with low or middle income.
• Nascence defects are the leading cause of babe mortality in the United States. In 1997,6,178 children died before their first birthdays considering they had ane or more birth defects. That number is 22 percent of all children who died underage ane.
• The most common birth defects involve the heart. About 28 percent of the children under age 1 who died of nascency defects in 1997 had issues with their hearts. The 2d most mutual category comprised defects of the respiratory arrangement, accounting for about 16 percent of the deaths that year.
• The decease rate from nativity defects in the The states dropped 37.7 per centum between 1979 and 1997. One reason for the decrease is improved medical care for infants with birth defects.
• Children with nascency defects who survive their showtime year still may die of complications from the defects later in life. In 1997,11,912 people of all ages died of nascence defects, with only near half under age i.
• Almost 150,000 babies a twelvemonth are born with a nascence defect in the United States. The charge per unit in the mid-1990s put the Us twenty-5th in the world, with twice as many birth defects per one,000 alive births as the nation with the lowest rate, Japan.

In a procedure called amniocentesis (am-nee-o-sen-TEE-sister), a small sample of fluid surrounding the fetus is removed through a needle and examined. This test is useful in detecting inborn metabolic (body chemistry) defects and abnormalities in the chromosomes.

Many birth defects tin be diagnosed by a physician's concrete test of a newborn baby. Other tests, including x-rays, may exist ordered if doctors suspect a birth defect; blood tests can notice certain disorders of the blood or body chemistry. Many infants with defects can develop normally if they receive prompt treatment.

How Do Doctors Care for Birth Defects?

Not every birth defect affects the quality of life of the person who has it. Some birth defects have little effect, except perhaps on appearance.

Several birth defects can exist treated to prevent or reduce their harmful effects. Surgeons can perform operations to right such malformations as clubfoot, scissure palate, crevice lip, and structural defects in the heart and digestive tract. Treatment can lessen the symptoms of cystic fibrosis, an inherited illness that interferes with breathing. In some cases, disorders such equally hydrocephalus (hy-dro-SEF-a-lus), a dissentious buildup of fluid in the head, can be remedied even earlier birth.

Doctors tin can sometimes treat inborn disorders of trunk chemistry with medications and special diets. For example, prompt treatment can prevent brain damage in phenylketonuria (fen-il-kee-to-NOOR-ee-a), or PKU, a metabolic defect that can produce severe mental retardation. Special education, rehabilitation, and the employ of special devices and machines can aid to starting time some mental and concrete handicaps, such equally blindness and deafness.

Thalidomide and
Phocomelia

Thalidomide is a sedative, a medication prescribed to at-home the nerves. If taken in the early months of pregnancy it tin can cause a birth defect called phocomelia (fo-ko-MEE-lee-a), in which the arms, legs, or both are very curt and underdeveloped.

Thalidomide was prescribed for pregnant women in Europe in the late 1950s and early on 1960s until it was linked to phocomelia in thousands of newborn babies. Fortunately for Americans, thalidomide never was sold in the United States because the U.S. Food and Drug Administration refused to approve information technology. An employee of this federal agency, Dr. Frances Kelsey, insisted that thalidomide's prophylactic had not been proven. Many people recollect Dr. Kelsey saved hundreds or fifty-fifty thousands of children from severe nativity defects.

The thalidomide tragedy led to an increase in government control over the marketing of drugs throughout the world, and the employ of thalidomide is now banned or strictly controlled in near countries.

Thalidomide may testify helpful in the treatment of such serious diseases every bit AIDS and leprosy, and researchers are continuing to report its therapeutic uses.

How Do Doctors and Parents-to-Exist
Forestall Nativity Defects?

No ane tin guarantee that a baby will be built-in "perfect" and salubrious. However, at that place are ways to minimize the likelihood of having a child with a

Professional lawn tennis instructor Butch Lumpkin was born with the short arms and deformed fingers characteristic of phocomelia, which resulted from the use of Thalidomide during pregnancy.

UPI/Corbis-Bettmnann.

preventable nativity defect. Some of the most of import ways involve lifestyle. A prospective mother should sympathize that many things she does may have an upshot on the new life growing inside her:

• Pregnant women should non smoke or beverage alcoholic beverages, nor should they use drugs of whatsoever kind unless prescribed past a doctor.
• Certain vitamins, if taken in proper amounts by the female parent-to-be, can aid prevent some nativity defects. For example, folate (folic acid) taken during pregnancy tin can aid prevent certain defects of the spinal column and central nervous system, including spina bifida.
• Vaccination well before pregnancy can preclude nascence defects that might occur if the mother were to develop German measles while pregnant.

Couples should seek genetic counseling earlier planning to have a child if the mother, father, or relatives have hereditary abnormalities.

Resource

Books

Kidd, J. S., and R. A. Kidd. Life Lines: The Story of the New Genetics. New York: Facts on File, 1999. This survey for young adults discusses the evolution of the written report of genetics.

Marshall, Elizabeth L. The Human Genome Project: Cracking the Lawmaking Inside Us. New York: Franklin Watts, 1997. A look at this international project and the scientists doing the research.

Organizations

U.S. Centers for Disease Command and Prevention (CDC). CDC posts several fact sheets about birth defects at its website.
http://www.cdc.gov/health/diseases.htm
http://world wide web.cdc.gov/nceh/programs/infants/brthdfct/prevent/bd_rev.htm

The March of Dimes Birth Defects Foundation, 1275 Mamaroneck Avenue, White Plains, NY 10605. The mission of this national system is to meliorate the wellness of babies by preventing birth defects and infant mortality. Its website offers information on the cause and prevention of nascency defects.
Telephone 888-663-4637
http://www.modimes.org

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Source: http://www.humanillnesses.com/original/At-Ca/Birth-Defects.html

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