Problems in Prenatal Development Chapter 4.2 Problems 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 Spina Bifida Cleft lip/palate Tay-Sachs Cystic Fibrosis Down Syndrome Muscular Dystrophy PKU Sickle Cell Anemia

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