Birth Defects

Birth Defects

• An abnormality that affects the structure or function of the body.

• Everyone is born with some type of imperfection (birthmark for example).

• Birth defects are children born with more serious problems.

Causes of Birth Defects

• Heredity– Inherited from one or both parents

• Environment–Controllable factors in the environment

• A combination of both heredity and the environment.

Environmental Influences

• Harmful substances taken by the mother–Over-the-counter medications–Prescription medications– Illegal drugs– Tobacco–Alcohol

Environmental Influences

• When the mother consumes harmful substances, the following can happen to the fetus:– Slow the fetal growth–Cause low birth weight babies–Varying levels of mental retardation–Malformations

Environmental Influences

• Toxoplasmosis• Hepatitis C• HIV and AIDS• Fifth disease• Chickenpox

• Cytomegalovirus• Group B

streptococcus• Rubella (German

measles)• Influenza

Diseases or infections from the mother

Helping to Prevent Birth Defects

• Avoid exposure to X-rays, pollutants, and toxic substances.

• Get appropriate rest and follow stress management techniques.

• Age of the mother–Risk for genetic birth defects increase if the

age of the mother is over 35.– Example – Down Syndrome

Helping to Prevent Birth Defects

• Seek early and continual medical attention/prenatal care.– Early = By the 13th week of pregnancy–Continual = At least 13 total visits over the

course of 40 weeks of pregnancy.• Maintain a proper diet.– The placenta does not transfer essential

nutrients to the fetus if a woman is undernourished.

Helping to Prevent Birth Defects

• Exercise–Walking and swimming

• Appropriate weight gain–24-30 pounds during pregnancy.

Helping to Prevent Birth Defects

• Receive proper immunizations prior to becoming pregnant.–Receiving the Rubella vaccine may be

dangerous for women who are pregnant.• Do not contract an STD/STI– Those infections are passed onto the fetus.

Folic Acid

• Helps to prevent neural tube defects.• Women of childbearing age who have

inadequate folate intakes are more likely to give birth to babies with neural tube damage.

• 400 micrograms of folic acid daily from supplements or fortified foods is recommended.

Folic Acid

• Neural tube damage occurs during the first weeks of pregnancy before a woman may realize she is pregnant.

• This may be prevented as a mother takes folic acid prior to conception.

Detecting Birth Defects

• Ultrasound–Utilizes sound waves to detect the health

and development of the fetus.• Amniocentesis– Inserting a needle through the abdominal

wall and into the uterus and withdrawing some amniotic fluid to detect birth defects.

Method of Inheritance

• Recessive Inheritance• Dominant Inheritance• Multi-factorial Inheritance• Chromosomal Error• Congenital Malformation• Blood Disorder• Prenatal Damage• Metabolic Disorder• X-Linked (Sex-Linked)

Recessive Inheritance

• Both genes in a pair must be defective to cause disease.

• People with only one defective gene in the pair are considered carriers.

• Examples include:– Sickle cell anemia–Cystic fibrosis

Dominant Inheritance

• The mutated gene is a dominant gene located on one of the nonsex chromosomes.

• You need only one mutated gene to be affected by this type of disorder.

• Examples include:–Huntington’s Disease

Multi-Factorial Inheritance

• Many factors are involved – heredity and environmental

• Combination of genes from both parents, in addition to unknown environmental factors, produce the

trait or condition.• Examples include:–Cleft lip/palate–Club hand/foot–Neural tube defects–Cerebral Palsy–Muscular

Dystrophy

Chromosomal Error

• The fertilized egg cell contains chromosomes in an abnormal structure, number, or arrangement.

• Examples include:–Down’s Syndrome

Congenital Malformation

• A condition that is present at birth.• Examples include:–Heart defects–Neural tube defects– Extra body parts (such as a finger)

Blood Disorder

• Affect any of the three main components of blood

• Red blood cells: Carry oxygen to the body’s tissues

• White blood cells: Fight infection• Platelets: Help blood to clot• Examples include:–Hemophilia and Anemia

Prenatal Damage

• Exposure to harmful agents during critical prenatal development which causes damage to the embryo or fetus before birth.

• Examples include:– Fetal alcohol syndrome– STD’s and STI’s

Metabolic Disorder

• Genetic conditions that result in metabolism problems.

• Metabolism: The chemical reactions taking place in the body to convert or use energy.

• Major examples of metabolism include:– Breaking down the carbohydrates, proteins and

fats in food to release energy.– Transforming excess nitrogen into waste products

excreted in urine

Metabolic Disorder

• Major examples of metabolism also include:–Breaking down or converting chemicals into

other substances and transporting them inside cells

• Examples include:– Tay-Sachs disease–PKU

X-Linked (Sex-Linked)

• Traits carried on the X chromosomes which makes females the carriers but the defect show up in the males.

• Examples include:–Hemophilia–Colorblindness–Muscular Dystrophy

Influences on Birth Defects

• Heredity–Down’s Syndrome–PKU–Muscular Dystrophy–Colorblindness–Hemophilia–Cystic Fibrosis

Influences on Birth Defects

• Environmental– Fetal alcohol syndrome (FAS)– STD/STI related

Influences on Birth Defects

• Combination of Heredity and Environmental–Cleft lip/palate–Club hand/foot–Cerebral palsy–Neural tube defects

Summary

• There are many factors that influence birth defects.

• Some you can prevent while others you cannot.

• Become aware of what you can do now to prepare to have a healthy child.

Birth Defects Presentations

• You will split into 12 groups.• Each group will research one birth defect.• You will then present your findings to the class

the next time we meet.• The class will take notes from your

presentation.