Chapter 4.2Problems in Prenatal Development

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

Dealing with Grief Very unexpected and

painful for the parents. Attachment during

pregnancy Grief similar to the

loss of a child already born

Support

Birth Defects Some babies survive pregnancy but with serious

problems. 120,000 babies are born each year in the United

States with birth defects

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

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

Birth Defects Cerebral Palsy Cleft lip/palate Cystic Fibrosis Down Syndrome Muscular Dystrophy PKU Sickle Cell Anemia

Spina Bifida Tay-Sachs

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

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

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.

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

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

Prenatal Tests More than 100 kinds of birth defects can now be detected before a

baby is born. Alpha-fetoprotein (AFP)

Performed 15-20 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

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