1. Problems in Prenatal Development
Chapter 4.2
Problems in Prenatal Development

2. Losing A Baby Expecting Mothers worry about the health of the newborn.
Miscarriage: the developing baby dies prior to the 20th week of pregnancy
Fairly common: 15% of pregnancies
Still Birth: when the developing baby dies after the 20th week.
2% of pregnancy

3. Dealing with Grief Very unexpected and painful for the parents.
Attachment during pregnancy
Grief similar to the loss of a child already born
Support

4. Birth Defects Some babies survive pregnancy but with serious problems.
120,000 babies are born each year in the United States with birth defects

5. Types and Causes of Birth Defects
Not all birth defects are obvious at birth; sometimes it may takes years for them to be discovered.
Scientists do not fully understand the causes for most birth defects; so far they have determine that there are 4 main causes
1. Factors in the Environment
2. Hereditary
3. Errors in Chromosomes
4. Combination of Environmental and Hereditary

6. Environmental Causes Early development of embryo is critical
1. Nutritional Balance
2. Diseases or infections the mother has during pregnancy
3. Harmful Substances
Alcohol, Tobacco, Over- the-Counter Meds, Illegal Drugs
4. Medications
5. Air Pollution
6. Exposure to X-Ray or high levels of radiation

7. Birth Defects Cerebral Palsy Spina Bifida Cleft lip/palate Tay-Sachs
Cystic Fibrosis
Down Syndrome
Muscular Dystrophy
PKU
Sickle Cell Anemia

8. Hereditary Causes Half of the genes from mother; half from father
Normal for a child to get 5-6 imperfect recessive genes
If they receive the same faulty gene from both parents this may cause the child to have a birth defect.
Recessive inheritance
Tay-Sachs and Cystic Fibrosis
Sometimes a child will inherit a defective gene that is dominant
Only needed from one parent
Dominant inheritance
Huntington's Disease (middle age)
Hemophilia-prevents blood from clotting
Color Blindness

9. Errors in Chromosomes
Several types of birth defects are caused by chromosomes.
An error may occur when the egg or sperm are developing.
Too many or too few chromosomes
Down Syndrome
May have some degree of mental retardation and physical problems
1 in 800 babies
Extra copy of chromosome 21; so instead of having 2 copies- they have three.
Higher risk for mothers who have children over the age of 35

10. Interaction of Heredity and Environment
Combination of heredity and environmental factors
Example:
Inherit a tendency that may lead to heart defect and drug use will bring out that tendency earlier.
Cleft lip/Palate and Spina Bifida are examples
Inherited traits along with the use of certain medications, infections, illnesses, or tobacco and alcohol.

11. Prevention and Diagnosis
Not all causes of birth defects can be anticipated or controlled.
Several things couples can do to lessen the chances
Checkups- Evaluate their overall health before conceiving
Lifestyle Changes (Before Pregnant)
Woman unaware of being pregnant
Once pregnant
Visit physician
Prenatal care
Avoid substances

12. Genetic Counseling History of birth defects
Family history
Already have a child with birth defects
Counseling can explain options and risks
Physical Exam
Blood Samples
Testing

13. Prenatal Tests
More than 100 kinds of birth defects can now be detected before a baby is born.
Alpha-fetoprotein (AFP)
Performed weeks. AFP is a protein in the liver of the fetus. Abnormal levels can indicate birth defects.
Ultrasound
Is a test that uses sound waves to make a video image of the unborn baby.
Image is called a sonogram
Amniocentesis
Withdrawing amniotic fluid surrounding the baby.
Cells are taken in for testing
Involves some risk to the fetus and is performed only when necessary

14. Prenatal Test Continued
Chorionic Sampling
Uses a sample of the tissue from the membrane that encases the fetus to check for specific birth defects.
This is used less often because it has higher risks ; but can be done much earlier than amniocentesis
New Prenatal Diagnosis
Several methods are now in experimental stages
Someday provide more accurate information