Birth Defects The Basics

Birth Defects Definition: An abnormality of structure, function or body metabolism which often results in a physical or mental handicap, shorter life or is fatal.

Classifications of Birth Defects 1. Structural - Club foot, clef palate 2. Metabolic -Heart/Circulatory 3. Congenital -Syphilis, HIV 4. Chromosomal -Down Syndrome 5. Other -FAS

Causes of Birth Defects and Percentages of Occurrence 1- Heredity 20% 2- Environment 3- Combination 60%

Prenatal Time Period Most Sensitive to Development The first trimester is the most important time period for prenatal development Baby develops all of its body systems in the first six weeks. Nourishment very important- Know you’re pregnant?

Factors Affecting Birth Defects 1- Heredity 2- Environment 3- When you catch it- can it be resolved?

Environmental Influences Lack of early medical attention Disease or infections of the mother medications: only under the care of your Doctor everything crosses the placenta Harmful substances ingested by the mother drugs, nicotine, alcohol causes slower fetal growth and transfers to the kidneys of the fetus causing damage

Environmental Influences Exposure to X-rays, pollutants, toxic substances Lack of folate, folic acid, folacin Lack of Exercise Helps with circulation Poor diet If the mother goes without so does the fetus

Environmental Influences Submersion in hot water Proper immunizations Too much, too little weight gain 24-30 lbs

Environmental Birth Defects Neural Tube Defects brain and spinal cord damage from lack of folic acid in the mother’s diet Fetal Alcohol Syndrome (FAS) physical and mental birth defects caused by excessive or steady alcohol consumption 100% preventable

Birth Defects- Heredity If you know you’re at-risk, talk with your Doctor before getting pregnant. Tests useful in detecting birth defects Ultrasound: sound waves produce a video image of the fetus Amniocentesis: needle in abdominal wall to withdraw amniotic fluid. 3-4 weeks Chorionic Villa Sampling: needle through vagina, cervix, and uterus to take cells from placenta- quick results

Sex-Linked Defects Color Blindness Baldness Etc.

The Rh Factor Blood cells of baby or mother crosses over to the other. Problem when they baby and mother are not the same blood factor Rh+ Rh-

An introduction to Genetics Heredity An introduction to Genetics

What are Genes? Genes are inherited traits Physical characteristics passed on to children contributed by both parents. There are 23 pairs of chromosomes in a fertilized cell- for a total of 46 chromosomes. - contained in the nucleus

Parents Children 2 b 1 a 4 d 3 c

a b 4 3 c 1 d 2

Woman’s sex cell: Ovum/Egg Man’s sex cell: Sperm

TWINS!!! Monozygotic: Siamese Twins: Dizygotic: Identical twins: Fertilized eggs splits. Siamese Twins: Monozygotic, but the egg does not complete the seperation of the cell- still attached somewhere. Dizygotic: Fraternal Twins: Two separate eggs are fertilized.

Factors to Increase Chances of Having Twins History of twins in family Taking increased amount of hormones Use of artificial hormones Ages 32-36 +

GENES Dominant Gene Dominant Inheritance Recessive Gene: Stronger gene- characteristics is produced. Dominant Inheritance Dd x dd 50/50 chance of inheriting a trait Recessive Gene: Weaker gene- they do not produce characteristics, but are carried only to produce when both parents carry. Dd x dd Recessive Inheritance Rr x Rr 50% chance

Terms Syndrome: Carrier: Congenital Malformation or Birth Defect Set of characteristics that identify a certain condition or characteristic Carrier: Person who carries and passes on a disease or condition without having it himself. Congenital Malformation or Birth Defect Defect present at birth Multifactoral defects: interaction of many genes with other genes or environmental factors. Chromosomal error: Fertilized egg cell contains chromosomes in an abnormal number, structure or arrangement.