Problems in Prenatal
Development
Miscarriage
• Loss of a baby PRIOR TO the 20th week
of pregnancy.
Stillbirth
Death of a baby AFTER the 20th week of
pregnancy.
Birth Defects
PKU
• Inability of body to process a common
protein.
Sickle Cell Anemia
• Malformed red blood cells interfere with
oxygen supply.
• http://www.webmd.com/video/sicklecell-miracle
Tay-Sachs Disease
• Lack of a certain blood chemical makes
body unable to process certain fats in
the brain and nerve cells.
Down Syndrome
• Extra chromosome 21 typically results in
mental retardation.
• http://www.webmd.com/video/downsyndrome-test
Causes of Birth
Defects
Environment
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Poor nutrition
Diseases
Harmful substances
Medicines
Exposure to hazards such as radiation
Heredity
• Inheritance of two defective recessive
genes.
• Inheritance of one defective dominant
gene.
Errors in Chromosomes
• Having too few or too many
chromosomes, broken or rearranged
chromosomes.
Interaction of Heredity and
Environment
• Inherited genetic predisposition toward
a defect coupled with exposure during
pregnancy to certain medications,
infections, or harmful substances.
What does a Genetic Counselor
Do?
• Uses information from physical exams
and medical history to assess a
couple’s risk for having a child with
certain birth defects.
Prenatal Tests
Alpha-fetoprotein (AFP)
• Mother’s blood is tested to detect
abnormal levels of protein AFP
• No known risk
Ultrasound or sonogram
• Sound waves are used
to make a video image
of the unborn baby.
• No known risk
• http://www.muscheal
th.com/video/Default
.aspx?videoid=1005
5
Mrs. Cissel’s Grandson
Baby Cohen
Amniocentesis
• A small amount of
amniotic fluid is
removed and tested.
• Some risk to fetus.
• http://www.muscheal
th.com/video/Default
.aspx?videoid=1005
5
Chorionic Villi Sampling
• Samples of tissue from
the membrane that
encases the fetus are
removed and tested.
• Greater risk than
amniocentesis
• http://www.muschealth.
com/video/Default.aspx
?videoid=10055
Avoiding Dangers
to the Baby
Alcohol
• Fetal Alcohol Syndrome
– Incurable condition found in some children
of mothers who consumed alcohol during
pregnancy
– Wide range of physical and mental
disabilities that last a lifetime
– Facial deformity, delayed physical growth,
heart defects, & hyperactivity
• Mental retardation and severe learning
problems
• Alcohol interferes with tissue growth
and development
• Brain tissue is easily injured by alcohol
• Poor coordination and difficulty
controlling behavior
Other Harmful Drugs
• Medicines – both over-the-counter and
prescription
• Caffeine – found in some foods and
beverages
• Nicotine and other toxic chemicals
found in cigarettes
• Illegal drugs and inhalants
X Rays
• Radiation can cause birth defects
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Hazardous Chemicals and
Substances
Paint
Pesticides used to exterminate bugs
Lead (in water and paint)
Carbon monoxide
Mercury (found in fish, such as swordfish and
shark)
• Solvents, paint thinners, and formaldehyde
(used in some workplaces)
Infections
• Some pose a greater risk than others
Rubella
• Can cause severe birth defects
• First three months most critical
– Blindness
– Deafness
– Heart disease
– Mental retardation
Toxoplasmosis
• An infection caused by a parasite
• Can cause blindness, hearing loss, & learning
disabilities
• Death or long-term mental disabilities
• Miscarriage or stillbirth
• A pregnant woman should never clean a cat’s
litter box, eat undercooked meat, and should
wash hands thoroughly and immediately after
touching raw meat.
Chicken Pox
• If an expectant mother gets chicken pox
during the first half of her pregnancy,
her baby is at slight risk of getting a
condition called “congenital varicella
syndrome”
– Scarring of the skin, limb defects, eye
problems, and other serious abnormalities,
miscarriage
Sexually Transmitted Diseases
• Some can be passed on to the child
during the birth process
– Syphilis, gonorrhea, hepatitis B, genital
herpes, AIDS, and Chlamydia
– Newborns are treated with a solution that
will kill any gonorrhea germs that could
cause blindness
AIDS
• 35 to 65% risk the virus will be passed
on to the baby.
• Attacks the brain
• The infected babies often have seizures
and retarded mental development.