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Can birth defects be treated before birth? Prenatal surgery

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Title: Can birth defects be treated before birth? Prenatal surgery


1
Can birth defects be prevented?
How many babies in the United States are born
each year with birth defects?
Does moderate or light drinking during pregnancy
harm the baby?
Can birth defects be treated BEFORE BIRTH?
Acne Medicine?
Which EXTRA chromosome does a person with Down
Syndrome have?
When do chromosomal abnormalities usually occur?
body chemistry?
What is Achondroplasia?
What are TERATOGENS?
How many genes do each of us have?
CAN DIABETES AFFECT PREGNANCY?
What causes birth defects?
folic acid?
ULTRASOUND
What are the most common birth defects?
2
FACTS
  • About 120,000 babies (1 in 33) in the United
    States are born each year with birth defects.
  • A birth defect is an abnormality of structure,
    function or metabolism (body chemistry) present
    at birth that results in physical or mental
    disabilities or death.
  • Several thousand different birth defects have
    been identified.
  • Birth defects are the leading cause of death in
    the first year of life.

BACK
3
What causes birth defects?
  • Both genetic and environmental factors, or a
    combination of these factors, can cause birth
    defects.
  • However, the causes of about 70 percent of birth
    defects are unknown.

BACK
4
Single gene defects
  • In many cases, a single gene change can cause
    birth defects.
  • Every human being has about 20,000 to 25,000
    genes that determine traits like eye and hair
    color.
  • Genes also direct the growth and development of
    every part of our physical and biochemical
    systems.
  • Genes are packaged into each of the 46
    chromosomes inside our cells.

BACK
5
Single gene defects
  • Each child gets half its genes from each parent.
    A person can inherit a genetic disease when one
    parent (who may or may not have the disease)
    passes along a single faulty gene.
  • This is called dominant inheritance. Examples
    include
  • Achondroplasia (a form of dwarfism)
  • Marfan syndrome (a connective tissue disease)

BACK
6
Single gene defects
  • Many other genetic diseases are inherited when
    both parents (who do not have the disease) carry
    an abnormality in the same gene and pass it on to
    a child. This is called recessive inheritance.
  • Examples include
  • Tay-Sachs disease (a fatal nervous system
    disorder)
  • Cystic fibrosis (a serious disorder of lungs and
    other organs, affecting mainly Caucasians)

7
Single gene defects
  • There also is a form of inheritance called
    X-linked, in which sons can inherit a genetic
    disease from a mother who carries the gene
    (usually with no effect on her own health).
  • Examples include
  • Hemophilia (a blood-clotting disorder)
  • Duchenne muscular dystrophy (progressive muscle
    weakness)

8
Chromosomal birth defects
  • Abnormalities in the number or structure of
    chromosomes can cause many birth defects.
  • Chromosomal abnormalities usually result from an
    error that occurred when an egg or sperm cell was
    developing.
  • As a result of this error, a baby can be born
    with too many or too few chromosomes, or with one
    or more chromosomes that are broken or
    rearranged.

9
Chromosomal birth defects
  • Down syndrome, in which a baby is born with an
    extra chromosome 21, is one of the most common
    chromosomal abnormalities.
  • Children with Down syndrome have varying degrees
    of mental retardation, characteristic facial
    features and, often, heart defects and other
    problems.
  • Babies born with extra copies of chromosome 18 or
    13 have multiple birth defects and often die in
    the first months of life.
  • Extra copies of most other chromosomes rarely
    allow survival to live birth and are common
    causes of miscarriage.

10
Chromosomal birth defects
  • Missing or extra sex chromosomes (X and Y) affect
    sexual development and may cause infertility,
    growth abnormalities and behavioral and learning
    problems.
  • However, most affected individuals live fairly
    normal lives.
  • Examples include
  • Turner syndrome (in which a girl is missing all
    or part of an X chromosome) and
  • Klinefelter syndrome (in which a boy has one or
    more extra X chromosomes).  

11
Environmental factors
  • Environmental substances that can cause birth
    defects are called teratogens.
  • These include
  • alcohol,
  • certain drugs/medications,
  • infections, and
  • certain chemicals.

12
Environmental factors
  • Each year between 1,000 and 6,000 babies are born
    with fetal alcohol syndrome (FAS) in this
    country.
  • FAS is a pattern of mental and physical birth
    defects that is common in babies of mothers who
    drink heavily during pregnancy.
  • Women who are pregnant or planning pregnancy
    should not drink any alcohol.
  • Even moderate or light drinking during pregnancy
    may harm the baby.

13
Environmental factors
  • Some drugs and medications can contribute to
    birth defects.
  • For example, the acne drug isotretinoin (sold
    under the brand names Accutane, Amnesteem,
    Claravis and Sotret) poses a high risk of serious
    birth defects. A woman who is pregnant or who
    could become pregnant should never use this drug.
  • Illicit drugs such as cocaine also may pose a
    risk.

14
Environmental factors
  • Certain infections can result in birth defects
    when a woman contracts them during pregnancy.
  • About 40,000 babies a year (about 1 percent of
    all newborns in this country) are born with a
    viral infection called cytomegalovirus (CMV). A
  • About 1 in 10 infected babies develop serious
    disabilities, including mental retardation and
    loss of vision and hearing.
  • Pregnant women often get CMV from young children
    who have few or no symptoms.

15
Environmental factors
  • Sexually transmitted infections in the mother
    also can endanger the fetus and newborn.
  • For example, untreated syphilis can result in
    stillbirth, newborn death or bone defects.
  • About 412 babies were affected by congenital
    syphilis in 2002.

16
Multi-factorial birth defects
  • Some birth defects appear to be caused by a
    combination of one or more genes and
    environmental exposures. This is called
    multi-factorial inheritance.
  • In some cases, an individual may inherit one or
    more genes that make him more likely to have a
    birth defect if he is exposed to certain
    environmental substances (such as cigarette
    smoke).
  • These individuals have a genetic predisposition
    to a birth defect.
  • But if the individual is not exposed to the
    environmental substance before birth, he probably
    wont have the birth defect.

17
Multi-factorial birth defects
  • Examples of multi-factorial birth defects
    include
  • Cleft lip/palate (opening in the lip and/or roof
    of the mouth)
  • Neural tube defects (serious birth defects of the
    brain and spinal cord, including spina bifida and
    anencephaly)
  • Heart defects

18
What are the most common birth defects?
  • Cleft lip/palate and Down syndrome are among the
    most common birth defects in the United States.
  • About 6,800 babies are born with cleft lip/palate
    each year. Cleft lip/palate can cause problems
    with eating, speech and language.
  • Some affected babies have a small cleft that can
    be corrected with one surgical procedure, while
    others have severe clefts and need multiple
    surgeries.
  • About 5,500 babies are born each year with Down
    syndrome.

19
What are the most common birth defects?
  • About 1,900 babies are born with a serious heart
    defect called transposition of the great arteries
    each year.
  • Many more babies are born with other serious
    heart defects. While advances in surgery have
    dramatically improved the outlook for affected
    babies, heart defects remain the leading cause of
    birth defect-related infant deaths.
  • Health care providers usually do not know what
    causes a babys heart to form abnormally,
    although both genetic and environmental factors
    play a role.  .

20
What are the most common birth defects?
  • Spina bifida (open spine) occurs in about 1,300
    babies each year.
  • Affected babies have varying degrees of paralysis
    and bladder and bowel problems.
  • Both genetic and environmental factors (including
    insufficient amounts of a vitamin called folic
    acid) appear to play a role.

21
What are the most common birth defects?
  • Other common birth defects include
    musculoskeletal defects (including arm and leg
    defects), gastrointestinal defects (including
    defects of the esophagus, stomach and intestines)
    and eye defects.
  • These birth defects usually are multi-factorial.

22
What are birth defects of body chemistry?
  • In 2002, about 3,000 babies were born with
    disorders affecting body chemistry (metabolic
    disorders).
  • These disorders are not visible, but they can be
    harmful or even fatal.

23
What are birth defects of body chemistry?
  • Most disorders of body chemistry are recessive
    genetic diseases.
  • These diseases result from the inability of cells
    to produce enzymes (proteins) needed to change
    certain chemicals into others, or to carry
    substances from one place to another. An example
    is
  • Tay-Sachs disease. Affected babies lack an
    enzyme needed to break down certain fatty
    substances in brain cells. These substances build
    up and destroy brain cells, resulting in
    blindness, paralysis and death by age 5.

24
What are birth defects of body chemistry?
  • Another example is phenylketonuria (PKU).
    Affected babies cannot process a part of protein,
    which builds up and damages the brain.
  • Newborn screening tests routinely detect babies
    with PKU, so they can be placed on a special diet
    that prevents mental retardation.
  • The March of Dimes recommends that all newborns
    be screened for 29 disorders (including hearing
    loss) for which effective treatment is available.

25
Can birth defects be prevented?
  • There are a number of steps a woman can take to
    reduce her risk of having a baby with a birth
    defect.
  • One important step is a preconception visit with
    her health care provider. During this visit, the
    provider can identify, and often treat, health
    conditions that can pose a risk in pregnancy,
    such as high blood pressure or diabetes.
  • The provider can provide advice on lifestyle
    factors, such as quitting smoking and avoiding
    alcohol, and occupational exposures that can pose
    pregnancy risks. The provider also can make sure
    that any medications a woman takes are safe
    during pregnancy.
  • All of these steps help prevent birth defects.

26
Can birth defects be prevented?
  • A preconception visit is especially crucial for
    women with chronic health conditions, like
    diabetes, high blood pressure and epilepsy, which
    can affect pregnancy.
  • For example, women with diabetes who have poor
    blood sugar control are several times more likely
    than women without diabetes to have a baby with a
    serious birth defect.
  • However, if their blood sugar levels are well
    controlled starting before pregnancy, they are
    almost as likely to have a healthy baby as women
    without diabetes.

27
Can birth defects be prevented?
  • At a preconception visit, the provider can check
    to see if a womans vaccinations are up to date.
  • If she is not immune to rubella and chickenpox,
    she should be vaccinated before pregnancy.
  • With widespread childhood vaccination, rubella is
    now uncommon. However, if a pregnant woman comes
    down with the disease, it poses a high risk of
    birth defects.
  • Chickenpox also can cause birth defects, though
    the risk is low.
  • A woman should wait for one month after being
    vaccinated before trying to become pregnant.

28
Can birth defects be prevented?
  • The provider also will ask a woman about her
    health history, as well as that of her partner
    and her family.
  • This may help the provider identify risk factors
    for birth defects or inherited genetic
    conditions.
  • The provider may refer couples with risk factors
    to a genetic counselor.
  • A genetic counselor can discuss the risks of
    birth defects in their children and arrange for
    blood tests (such as carrier tests), when needed.

29
Can birth defects be prevented?
  • All women who could become pregnant should take a
    daily multivitamin containing 400 micrograms of
    the B-vitamin folic acid.
  • Studies show that taking this vitamin before and
    during early pregnancy reduces the risk of having
    a baby with neural tube defects (spina bifida and
    anencephaly).
  • If a woman already has had a pregnancy affected
    by one of these birth defects, she should consult
    her provider before pregnancy about how much
    folic acid to take.
  • Generally a higher dose, 4 milligrams, is
    recommended Women with diabetes or epilepsy or
    who are obese are at increased risk of these
    birth defects. They should ask their providers
    before pregnancy about whether they should take
    the larger dose of folic acid.

30
Can birth defects be prevented?
  • A woman who is pregnant or planning pregnancy
    should avoid drinking alcohol, smoking and using
    drugs.
  • All of these can cause birth defects and other
    pregnancy complications. She should not take any
    medication (prescription, over-the-counter or
    herbal) without first checking with her health
    care provider.
  • She should also avoid changing the cats litter
    box or eating raw or undercooked meat. These are
    possible sources of an infection called
    toxoplasmosis that can cause birth defects.

31
Can some birth defects be diagnosed before birth?
  • Some birth defects can be diagnosed before birth
    using one or more prenatal tests, including
    ultrasound, amniocentesis and chorionic villus
    sampling (CVS).
  • Ultrasound can help diagnose structural birth
    defects, such as spina bifida, heart defects and
    some urinary tract defects.

32
Can some birth defects be diagnosed before birth?
  • Amniocentesis and CVS are used to diagnose or
    rule out chromosomal abnormalities, such as Down
    syndrome, and numerous genetic birth defects.
  • Most women have screening tests (blood tests) to
    see if they are at increased risk of certain
    birth defects, including Down syndrome and spina
    bifida.
  • These screening tests cannot diagnose a
    condition, but they can suggest that further
    diagnostic testing is needed.

33
Can birth defects be treated before birth?
  • A small percentage of couples learn through
    prenatal diagnosis that their baby has a birth
    defect.
  • While this news can be devastating, prenatal
    diagnosis sometimes can improve the outlook for
    the baby.
  • It is now possible to treat some birth defects
    before birth.
  • For example,
  • biotin dependence and methylmalonic academia (two
    life-threatening inherited disorders of body
    chemistry) have been diagnosed by amniocentesis
    and treated in the womb, resulting in the births
    of healthy babies.

34
Can birth defects be treated before birth?
  • Prenatal surgery has saved babies with urinary
    tract blockages and rare tumors of the lung. More
    than 300 babies have undergone experimental
    prenatal surgery to repair spina bifida before
    birth. Prenatal surgery poses a number of serious
    risks for mother and baby, including preterm
    birth.
  • (The National Institutes of Health is currently
    conducting a study through 2007 to compare the
    safety and effectiveness of surgery before and
    after birth for babies with spina bifida. For
    information contact http//www.spinabifidamoms.com
    /.)
  • Doctors also have saved babies with serious heart
    rhythm disturbances by treating the pregnant
    woman with medications.

35
Can birth defects be treated before birth?
  • However, even when a fetus has a condition for
    which prenatal treatment is not yet possible,
    prenatal diagnosis permits parents to prepare
    themselves emotionally, and to plan with their
    provider the safest timing, hospital facility and
    method of delivery.
  • Couples who have had a baby with a birth defect,
    or who have a family history of birth defects,
    should consider consulting a genetic counselor.
    These health professionals help families
    understand what is known about the causes of a
    birth defect, and the chances of the birth defect
    recurring in another pregnancy.
  • Genetic counselors can provide referrals to
    medical experts as well as to appropriate support
    groups in the community. The National Society of
    Genetic Counselors provides the names and contact
    information of genetic counselors.
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