Birth Defects

What are Birth Defects?

According to the March of Dimes, there are about 150,000 babies born each year in the United States that have birth defects. Birth defects are defined as abnormalities of structure, function, and/or metabolism that are present at birth. They are the results of an error in the way bone, brain, skin or tissue were developed. These abnormalities result in either a physical or a mental disability, or are fatal. According to the Center for Disease Control and Prevention (CDC), about 8,000 of these babies die in their first year of life. However, many are treatable, often immediately after birth and sometimes even before the baby is born and some can be prevented. A disorder may or may not be inherited (passed from parent to child via genes and chromosomes) but most children born with congenital defects are born to two healthy parents. Although many birth defects can be seen right away, others appear later in life even though they too were present at birth.

What are the causes?

Genetic and/or environmental factors can cause birth defects. It should be pointed out, however, that at least 60 percent of the causes of birth defects are unknown. When genetics are the cause, it is due to one missing or faulty gene. Every cell in the body has chromosomes containing genes that determine a personÕs characteristics. Each child receives half its genes from each parent. The faulty genes come from three main sources:

Dominant inheritance Ð when a child inherits a genetic disease from one parent who has the disease. This would include birth defects such as achondroplasia (a form of dwarfism) and Marfan syndrome (a disorder characterized by abnormally long fingers, arms and legs).
Recessive inheritance Ð when both parents (who are healthy) pass along a faulty gene of the same disease to the child. This includes conditions such as Tay-Sachs disease (a fatal disorder seen mainly in people of European Jewish heritage) or cystic fibrosis (a fatal disorder of the lungs and other organs affecting mainly Caucasians).
X-linked inheritance Ð where sons can inherit a genetic disease from a healthy mother who carries the gene. Examples would include hemophilia (a blood clotting disease) and Duchenne muscular dystrophy (progressive muscle weakness.

In addition, abnormalities in the number or structure of chromosomes can cause birth defects. Down syndrome is one of the most common examples. A baby born with Down syndrome has an extra chromosome 21. The risk of this type of birth defect increases with the age of the mother.

Environmental causes have to do with the motherÕs health and exposure to chemicals or diseases. For example, alcohol abuse by the mother while pregnant can cause fetal alcohol syndrome, and certain medications can cause birth defects. Mothers who use cocaine in early pregnancy increase the babyÕs risk of having a birth defect. Studies have suggested that these babies are five times more likely to be born with urinary tract defects. When a pregnant woman is exposed to certain infections, such as rubella, it can also cause birth defects.

Is there Prevention?

Although many birth defects cannot be prevented, there are precautions that a woman can take before and during pregnancy. These would include:

Make sure her vaccinations are up to date.
Make sure she has no sexually transmitted diseases.
Make sure she is getting the recommended dose of B-vitamin folic acid, (400 micrograms) in a daily vitamin or prenatal vitamin. (Higher doses of the B-vitamin folic acid are sometimes recommended if the mother has given birth to babies who have these defects, however it is imperative that a woman consult with her healthcare provider before taking any medications, including prenatal vitamins.) Studies show that taking this vitamin before and in the early weeks of pregnancy reduces the risks of certain birth defects of the brain and the spine, including spina bifida.
Consulting a genetic counselor if either parent has a history of any kind of birth defect in their families, or if they are a part of a high-risk group due to age, ethnic background, or medical history.
Avoiding Smoking
Avoiding Alcohol
Avoiding all illicit drug
Eating a healthy diet
Getting exercise and plenty of rest
Getting early and regular prenatal care

Birth Defect Categories:

Birth defects are usually grouped into three major categories:

Structural/metabolic abnormalities: structural would include heart defects and spina bifida, and the metabolic would include Tay-Sachs disease. (Tay-Sachs is a disease in which the babies lack an enzyme needed to break down certain fatty substances in the brain and nerve cells.)
Congenital infections: Rubella (German Measles) is an example of a congenital infection that can cause birth defects. Untreated syphilis is another example that can result in stillbirth, newborn death, or birth defects involving the bones. (According to the March of Dimes about one baby in 2,000 is born with congenital syphilis.)
Other conditions/causes: These would include fetal alcohol syndrome, Rh disease (which is caused by an incompatibility between the blood of the mother and the fetus, affecting approximately 4,000 infants a year. It can be prevented by giving an Rh-negative woman an injection of a blood product called immunoglobulin at 28 weeks of pregnancy and after the delivery of an Rh-positive baby.), and babies who are borne to women who used cocaine early in pregnancy.

Following are some examples of the more common birth defects and include a broad representation of organ systems that are affected.

The Nervous System

Cerebral Palsy: Cerebral palsy, also known as CP, is a term used to describe any number of various non-progressive disorders characterized by the impairment of voluntary movement. "Cerebral" means having to do with the brain, and "palsy" means problems or weaknesses with using the muscles or joints in the body. Having CP means that because of an injury to the brain, a baby is not able to use their muscles in a normal way. As the infant grows it may not be able to walk, talk, eat or play in the same way as other children. Some children with CP have learning problems, problems with vision or hearing, or even mental retardation. The more severe the brain injury, the more severe the CP. CP does not get worse over time, is not a disease or an illness, is not contagious, and while it is not something that is grown out of, most children with CP have a normal life span.

There are three main types of Cerebral palsy:

Spastic CP Ð this is when there is too much muscle tone or tightness. Movements in the legs, arms and/or back are stiff.
Ataxic CP Ð this describes low muscle tone and poor coordination of movements.
Athetoid CP (also called dyskinetic CP) Ð is characterized by fluctuations in muscle tone (varying from too tight to too loose) and sometimes is associated with uncontrolled movements. It affects the entire body, and because the muscles of the face and tongue can be affected, there can be difficulties with sucking, swallowing, and speech.
Mixed CP Ð this is when a child has both high and low muscle tone. Some of the muscles will be too tight and others will be too loose. There will be a mix of stiffness and involuntary movements. About one-fourth of all people with CP have this type of CP.

The following are some words that are used to describe the different parts of the body that are affected by CP:

Diplegia Ð only the legs are affected.
Hemiplegia Ð one half of the body is affected.
Puadriplegia Ð both arms and legs are affected (sometimes this includes the facial and torso muscles).

Treatment:

Treatment for CP should include early intervention for children younger than three and special education and related services for older children. The effects of CP can be reduced by the use of early and ongoing treatment.

Treatments may include:

Physical therapy
Occupational therapy
Speech therapy
Hearing aid
Eyeglasses or eye surgery
Joint surgery
Medications

According to the National Information Center for Children and Youth with Disabilities, about 500,000 people in America have some form of CP. Each year 8,000 infants and nearly 1,500 preschool-age children are diagnosed with CP. Children with CP benefit from educational and therapy services, which are available from birth in most states.

Prevention:

The cause of CP is not known in many cases, so there is nothing that can be done in most cases, to prevent it. Due to the increasing survival rate of very premature babies, the number of CP cases seems to be increasing. Therefore, the most helpful prevention is likely to be avoiding premature birth. Other steps might include:

Making sure you are immunized
Keep yourself healthy
Seek early and continuous prenatal care

Spina Bifida: Spina Bifida is among the most common severe birth defects in the United States, according to the March of Dimes. It affects 1,500 to 2,000 babies each year. It is the most common of a group of defects called neural tube defects (NTDs). It is often called "open spine", and it affects the backbone and sometimes the spine. In the embryo, there is a tiny ribbon of tissue that folds inward to form a tube. This structure, called the neural tube is formed by the 28th day after conception. When the neural tube does not close completely, defects can occur. There are three forms of spina bifida:

Occulta Ð there is a small defect or gap in one or more of the vertebrae of the spine. Most affected individuals have no problems.
Meningocele Ð this is the rarest form. There is a cyst or lump of membrane that surrounds the spinal cord and pokes through the open part of the spine. The cyst, can be removed surgically, allowing for normal development.
Myelomeningocele Ð this is the most severe form, in which the cyst holds both the membranes surrounding the spinal canal and the nerve roots of the spinal cord, and sometimes the cord itself. There may also be no cyst, only a fully exposed part of the spinal cord and nerves. The back can be closed surgically, although affected babies are at high risk for infection, in which case antibiotic treatment may offer temporary protection. Some degree of leg paralysis, bladder and bowel control problems may remain, despite surgery. Surgery is usually required within the first 24 to 48 hours after birth.

Spina Bifida is usually an isolated birth defect. Ninety-five percent of babies with spina bifida and other NTDs are born to parents with no family history of these disorders. It does appear to run in families, but it does not follow any particular pattern of inheritance. Spina Bifida can occur as part of a syndrome with other birth defects.

Women with diabetes and seizure disorders (treated with certain anticonvulsant medications) have an increased risk of having a baby with spina bifida.

While there is no prevention per se for spina bifida, the March of Dimes recommends that women take a multivitamin containing 400 micrograms of folic acid daily and eat a healthy diet containing foods rich in folic acid.

The key is having enough of the folic acid in the motherÕs system before pregnancy, and in the earliest weeks of pregnancy.

Early prenatal care is also highly recommended for all women who become pregnant. When spina bifida is diagnosed before birth, health care providers can give parents not only much needed information, but also support. Necessary surgery or treatment can be planned immediately for after birth if the delivery takes place in a specially equipped medical center.

Genetic counseling is recommended for parents who are at risk for having babies with spina bifida. Genetic counselors can explain prenatal testing for NTDs.

The Cardiovascular System

Truncus arteriosus: In this type of congenital heart disease, a single arterial trunk arises from the ventricle, and supply the pulmonary (lung), coronary (heart), and systemic (body) circulation. Affected people often have shortness of breath (dyspnea), fatigue and heart failure. Children with this heart disease have poor growth and physical development. Untreated, this condition can be fatal in the first few years of life.

Prevention: No known prevention

Symptoms:

Lethargic infant
Poor feeding
Shortness of breath
Fatigue
Cyanosis
Delayed growth or growth failure
Broadening of the finger tips (clubbing)

Diagnosis:

An ECG shows signs of enlargement of the heart (ventricular hypertrophy)
An X-ray of the chest shows heart enlargement
During heart catheterization, a definitive diagnosis is made by showing the abnormal appearance of the blood vessels
An echocardiogram shows a VSD (ventricular septal defect) and a single truncal artery.

Treatment:

Surgery (that could include one of two procedures: banding of the pulmonary arteries coming off the truncus, or complete repair) is needed to treat this condition. Complete repair is usually the preferred option. However, as the child grows repeat surgical procedures may be necessary. Complete repair can produce good results, while untreated cases have a poor outcome. Children with truncus arteriosus need lifelong follow-up to see how well the heart is working.

Tetralogy of Fallot: Tetralogy of Fallot is a combination of four heart defects. The two major components are a large hole, or ventricular septal defect that allows blood to pass from the right to the left ventricle without having to go through the lungs, and a narrowing (stenosis) at or just beneath the pulmonary valve. The other two components are: the right ventricle being more muscular than normal, and the aorta lying directly over the ventricular septal defect.

Tetralogy of Fallot results in cyanosis (blueness). It may appear soon after birth, in infancy or later in childhood. These babies may have episodes of blueness with rapid breathing. They may become unconscious. Older children may experience shortness of breath and episodes of fainting, while involved in exercise.

Most children with this defect have open-heart surgery before school age. The operation involves closing the ventricular septal defect and removing the obstructing muscle. After surgery, the long-term outlook varies, depending on how severe the defects were before surgery.

While most congenital heart defects cannot be prevented, there are some steps that a woman can take that may help reduce the risk. A woman should be tested before pregnancy for immunity to rubella, and vaccinated, if she is not immune. Pregnant women should avoid alcohol and drugs. Those with chronic health problems such as diabetes, seizure disorders, and PKU should consult their doctors before they attempt to conceive so that their medications can be adjusted.

Alimentary Tract

Cleft lip or palate: A cleft lip is an opening in the lip, and a cleft palate is an opening in the roof of the mouth. Clefts result from incomplete development of the lip or palate while the baby is forming before birth. BabiesÕ lips and palates develop separately during the first three months of pregnancy. In most cases, the left and right parts of the lip come together, or "fuse", creating the two vertical lines on the normal upper lip. In a similar way, the left and right parts of the palate come together to create a normal palate. The front to back line that can usually be seen along the roof of a normal mouth indicates where "fusion" occurred.

A cleft lip appears as a narrow opening or gap in the skin of the upper lip, usually all the way to the nose. The front part of the palate is bony and is called the anterior or hard palate. The rear or posterior palate is called the soft palate. A cleft palate can extend through both the hard and soft palates or there may be only partial clefting.

Both cleft lip and cleft palate can be treated. Most children born with either one or both of these conditions can have reconstructive surgery while they are still infants.

Feeding may be a problem for some babies, however special nipples and prostheses are available to ensure that these babies receive adequate nutrition until surgery can be provided.

Clefting is believed to be caused by a combination of genetic and environmental factors. The risk is higher for children whose siblings or parents have a cleft or if there is a history of clefting in the family.

There are three different categories of clefts:

Cleft lip without a cleft palate
Cleft palate with a cleft lip
Cleft lip and cleft palate together

Also, cleft can be unilateral (occurring on one side of the mouth) or bilateral (occurring on both sides of the mouth).

Treatment for clefts usually begins in infancy and often continues through early adulthood. It might include:

Dental care and orthodontia
Speech therapy
Plastic surgery
Help dealing with emotions and social issues
Continuous monitoring for hearing problems

Again, as with other birth defects, there is little know about how to prevent clefts. However, it is suggested that:

Women who are planning on a pregnancy take a multivitamin containing folic acid prior to, and during early pregnancy.
Abstain from nicotine, alcohol and other drugs during pregnancy
Checking with health care provider to ensure that any medications that are taken to treat certain conditions, such as epilepsy, are safe for pregnant women.

Pyloric stenosis: Pyloric stenosis, also known as Hypertrophic pyloric stenosis and/or gastric outlet obstruction, is a narrowing of the outlet from the stomach to the small intestine (called the pylorus) that occurs in infants. This condition is caused by a thickening of the muscles of the pylorus, which stops the stomach from emptying into the small intestine. It occurs more often in males than in females, and is thought that genetic factors may play a role, although the cause is unknown.

Symptoms appear several weeks after birth and include:

Vomiting (mild at first and becoming progressively more forceful within one half hour of feeding) Ð projectile vomiting
Infant appears to be constantly hungry
Diarrhea (loose green stools)
Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs
Dehydration (becoming more profound with the severity of the vomiting)
Failure to gain weight
Weight-loss
Abdominal fullness prematurely after meals
Belching
Apparent abdominal pain

Diagnosis:

Palpation of the abdomen reveals an olive-shaped mass during examination. A chemistry panel often reveals electrolyte imbalances.

A barium X-ray reveals a distended stomach and narrowed pylorus. An ultrasound of abdomen may also be performed.

Treatment consists of a surgical procedure to split the over-developed muscles of the pylorus. Rehydration with intravenous fluids usually takes place prior to surgery. Small, frequent feedings are usually well tolerated several hours after the surgery.

Prognosis:

There is usually complete relief of all symptoms following an adequate and successful surgical repair.

Genitourinary Renal agenesis; also known as Potter syndrome:

Potter syndrome and Potter phenotype is a complex of findings associated with renal failure that develops before an infant is born, and with a lack of amniotic fluid. Potter phenotype describes the absence of amniotic fluid (oligohydramnios). In the absence of amniotic, fluid the infant is not cushioned from the walls of the uterus. The pressure of the uterine wall causes a typical facial appearance (PotterÕs facies):

Widely separated eyes with epicanthal folds
Broad nasal bridge
Low set ears
Receding chin

Limbs may be abnormal or held in abnormal positions or contractures. Oligohydramnios also stops the development of the lungs (hypoplastic lungs). At birth, the lungs do not function properly.

The primary defect is renal failure that occurs before the baby is born. This is caused from either the failure of the kidneys to develop (bilateral renal agenesis) or from other diseases of the kidney, which cause them to fail.

Renal agenesis also refers to the absence of one or both kidneys. If one kidney is missing the prognosis is good unless there are other complications. If both kidneys are absent, death occurs shortly after birth.

Symptoms would include:

Potter facies (described above)
Absence of urine output
Respiratory distress
Stiff lungs during resuscitation effort (require high ventilation)
Oliohydramnios (absence of amniotic fluid)
Urogenital abnormalities

Treatment would include:

Resuscitation at delivery (this might be attempted pending the diagnosis)
Treatment provided for any urinary outlet obstruction

There is no known prevention, and this condition is usually fatal.

Abdominal Wall

Omphalocele: Omphalocele is a malformation in which the abdominal organs (such as the intestine and the liver), enclosed in a transparent sac, protrude through an enlargement of the opening at which the umbilical cord enters the abdomen. This may be associated with more serious abnormalities. It is a herniation of the intestine or other abdominal contents through which the umbilical root is covered only by peritoneum (the abdominal membrane) rather than skin.

There are different sizes of omphaloceles.

This condition is diagnosed via a physical examination. Testing is usually not necessary.

An omphalocele is considered a surgical emergency due to the considerations of infection and the drying out of the abdominal contents. If the abdominal cavity is too small and unable to contain the external portion of the gut, then the omphalocele is cover with a sack of biocompatible synthetic material. It is then sutured to the margins of the abdominal defect and slowly over time the volume of the sack is decreased. This causes the abdomen to stretch. When the omphalocele can comfortably fit within the abdominal cavity, the synthetic material is removed and the abdomen is closed. Complete recovery is expected. However, the health care provider should be contacted immediately, if any of these symptoms occur after returning home (following the repair):

Feeding problems
Vomiting (not normal baby spitting)
Green or yellowish green vomitus
Distended abdomen
Decreased stooling
Fever
Behavioral changes that you find worrisome

Gastroschisis: Gastroschisis is a herniation of the abdominal contents through a defect in the abdominal wall. It differs from an omphalocele in that it does not involve the umbilical cord (although it is near the cord) and the gastroschisis herniation is not covered with peritoneum.

As in omphaloceles, the abdominal cavity may be small and replacement of the bowel into the cavity may require several weeks in which the abdominal cavity is stretched to accommodate the mass.

Symptoms would include:

Lump in the abdomen
Intestine protruding through the abdominal wall near the umbilical cord (navel)
The unprotected intestine is exposed to irritating amniotic fluid, and as a result gut motility and absorption may be affected.

Treatment consists of surgically replacing the bowel into the abdomen, and the defect is then closed if there is adequate room. If the cavity is too small, a mesh sack is sutured around the margins of the abdominal defect and the edges of the defect are pulled up. Gravity draws the herniated intestine back into the abdominal cavity, slowly stretching it to the point where the defect can be closed.

Recovery is good if the abdominal cavity is relatively large enough.

Chromosomal Abnormality

Down syndrome: Down syndrome is a variable combination of birth defects including mental retardation and characteristic facial features. About 40 percent of babies with this condition also have congenital heart defects, and many have some visual and hearing impairment and/or various other health problems. There is much information available for parents, of babies who have Down syndrome that will not be covered in this article. This article will touch on the main features of this condition.

The main causes of Down syndrome occur when a child is born with three, rather than two, copies of the 21st chromosome. This is known medically as trisomy 21. Normally there are 46 chromosomes (23 pairs), half of which are inherited from each parent, the extra one being a third chromosome. It is this extra genetic material in infants with Down syndrome that disrupts their physical and cognitive development.

There are no know reasons why this syndrome occurs, however, scientists do know that women ages 35 and older have a significantly increased risk of giving birth to a child with Down syndrome. By age 40, this risk increases to about one in 100. By the age of 45, the odds are one in 30.

Not all Down syndrome infants share the same distinguishing physical characteristics. A preliminary diagnosis can usually be made at birth just by looking at the baby. If Down syndrome is suspected, a karyotype (a blood tissue sample stained to show chromosomes grouped by size, number and shape) will be performed to verify the diagnosis..

The most familiar physical traits of Down syndrome include:

Low muscle tone (muscle hypotonia)
Flat facial profile, including a somewhat depressed nasal bridge and small nose
Upward slant to the eyes (oblique palpebral fissures)
Abnormal shape and small size of the ears (dysplastic ears)
Single deep crease across the center of the palm (simian crease)
Excessive ability to extend the joints (joint hypermobility)
Fifth finger has one bending joint instead of two (dysplastic middle phalanx)
Small skin folds on the inner corners of the eyes (epicanthic folds)
Excessive space between large and second toe (sandal gap)
Enlargement of tongue in relationship to size of mouth

Children with Down syndrome can exhibit these traits in varying degrees.

In addition to the traits listed above, half of the children born with Down syndrome have congenital heart defects. The majority of these defects can be corrected, resulting in long-term health improvements. Children with Down syndrome are also susceptible to infection, respiratory problems, obstructed digestive tracts (early in infancy), and childhood leukemia. Recent medical advances have made most of these problems treatable.

People born with Down syndrome now have an average life expectancy of 55 years.

Treatment, following any necessary medical treatments, involves early intervention and inclusion. The Individuals with Disabilities Education Act (IDEA) protects the educational rights of children with disabilities. The law guarantees "a free appropriate education in the least restrictive environment" and an individualized program (IEP) for each child. This means that a child with Down syndrome could attend the same school as his/her siblings. The group notes, however, that individual pupilÕs educational needs may be met in various ways. IDEA also requires that local school districts provide free preschool services for children with disabilities starting at the age of three.

While the law does not mandate preschool services before the age of three, some states offer free early intervention from birth to age two. Such services, which can include physical, speech, and occupational therapy, is recommended as soon as possible after birth. Therapists and educators in early intervention programs can teach parents how to help their babies develop gross motor and fine motor skills, language, social development, and self-help skills.

Other

Fetal Alcohol Syndrome: Alcohol is the leading known cause of mental and physical birth defects, surpassing both spina bifida and Down syndrome. Alcohol produces more severe abnormalities in a developing fetus than heroin, cocaine, or marijuana. It is also the most common preventable cause of birth defects in the United States.

Fetal Alcohol Syndrome (FAS) is a pattern of physical, developmental, and functioning abnormalities in a child, resulting from a womanÕs drinking alcohol during pregnancy. Characteristics of children with FAS include:

Low birth weight
Small head circumference
Failure to thrive
Developmental delay
Organ dysfunction
Facial abnormalities, including smaller eye openings, flattened cheekbones, and indistinct philtrum (an underdeveloped groove between the nose and the upper lip)
Epilepsy
Poor coordination/fine motor skills
Poor socialization skills, such as difficulty building and maintaining friendships and relating to groups
Lack of imagination or curiosity
Learning difficulties, including poor memory, inability to understand concepts such as time and money, poor language comprehension, poor problem-solving skills
Behavioral problems, including hyperactivity, inability to concentrate, social withdrawal, stubbornness, impulsiveness, and anxiety.

Children with FAE (Fetal Alcohol Effects) display the same symptoms, but to a lesser degree, and are less likely to have mental retardation.

It is clear that abusing alcohol during pregnancy is dangerous. Because alcohol easily passes the placental barrier and the fetus is less equipped to eliminate alcohol than its mother, the fetus tends to receive a high concentration of alcohol, which lingers for longer periods than it would in the motherÕs system. While no evidence exists that can determine how much alcohol will produce birth defects, it is suggested by many health care providers that women who are considering becoming pregnant, or who are already pregnant abstain from any alcohol consumption.

As with any medical condition, always seek the best help and information available from your health care provider.

This article is for information only, and does not constitute medical advice.

Other Resources:

The Cleft Palate Foundation 1829 E. Franklin Street Suite 1022 Chapel Hill, NC 27514 http://www.cleftline.org/

Spina Bifida Association of America 4590 MacArthur Boulevard, NW., Suite 250 Washington, DC 20007-4226 Telephone: 202/944-3285 or 1-800-621-3141 Web address: www.sbaa.org

United Cerebral Palsy Associations, Inc. 1660 L Street NW, Suite 700 Washington, DC 20036 (800) 872-5827 (voice/TTY) (202) 776-0406 (voice) (202) 973-7197 (TTY) ucpanatl@ucpa.org (E-mail) www.ucpa.org (Web)

Easter Seals Ð National Office 230 West Monroe Street, Suite 1800 Chicago, Illinois 60606-4802 (800) 221-6827 (voice) (312) 726-6200 (voice) (312) 726-4258 (TTY) info@easterseals.org (E-mail) www.easter-seals.org (Web)

National Information Center for Children and Youth with Disabilities PO Box 1492 Washington, DC 20013 (800) 695-0285 (voice/TT) (202) 884-8200 (voice/TT) nichcy@aed.org (E-mail) www.nichy.org (Web)