Lecture 19: Birth Defects Flashcards
What is a “birth defect?”
abnormality or structure, function or metabolism present at birth that results in physical or mental disabilities or death
What is a “congenital” effect?
a physical anomaly which is recognizable at birth
What are some single gene defects?
5
- Tay-Sachs
- Achondroplasia
- Cystic Fibrosis
- Hemophilia
- Duchenne Muscular Dystrophy
What are chromosomal defects?
too many or two few chromosomes (aneuploidy), or with one or more chromosomes that are broken or rearranged
What are some examples of chromosomal defects?
- Trisomy 21 (down syndrome)
- Trisomy 18 or 13
- Missing or extra chromosomes (e.g., Turner syndrome)
What are some environmental factors of birth defects?
- Teratogens
- Alcohol
- Drugs/ Medication
- Infetions
How much folic acid should a pregnant woman take?
between 400 micrograms to 4mg
When does Neural Tube Formation takes place?
15-28 days of development, from fertilization
What happens during “Anencephaly?”
- Upper part of neural tube does not close all the way
- Baby is born without parts of brain and skull
What happens during “Spina Bifida?”
- It can happen anywhere along spine where lower part of neural tube does not close all the way
- Causes physical and mental disabilities that range from mild to severe
Folic acid is necessary for DNA____, DNA_____ and DNA_____ and it acts as a co-factor in ______reactions
synthesis, repair, methylation
biological
Folic acid is important for rapid ____ and _____
division; growth
How can birth defects be diagnosed BEFORE birth?
4
- Blood tests
- Ultrasound
- Chorionic Villus Sampling
- Amniocentesis
What does Cell-free fetal DNA accomplish?
- most reliable for sex determination
- Use to diagnose Trisomy 21 and 18 and single gene defects of parental origin
What are the 2 types of blood tests done in First-Trimester ultra-screen?
- Pregnancy-associated Plasma Protein A (PAPP-A)
Human Chorionic Gonadotropin (hCG)
What is the type of blood tests done in Second trimester? Quad Screen?
- Alpha-Fetoprotein (AFP)
- hCG, Estriol and possibly inhibin
What does the 1st Trimester US accomplish?
6
- Dates of pregnancy
- detects HB
- Detects Fetal movement
- Determines the # of fetuses and identify placental structures
- Diagnose ectopic or miscarriage
- Nuchal Translucency Screen
What does the 2nd Trimester US accomplish?
8
- Examine fetal anatomy for presence of abnormalities
- Check amount of amniotic fluid
- Examine blood flow patterns
- Observe fetal behavior and activity
- Examine Placenta
- Measure length of cervix
- Monitor fetal growth
- Discover sex of fetus around 14 weeks
What does the 3rd Trimester US accomplish?
4
- Monitor Fetal Growth
- Check amount of amniotic fluid
- Determine position of fetus
- Assess placenta
What does Chorionic Villus Sampling (CVS) do? What does it not do?
- Takes sample of placental tissue under ultrasound, and tests for chromosomal abnormalities and other genetic defects.
- Does not provide information on neural tube defects
What does an Amniocentesis discover? what does it show?
- Amniotic fluid contains cells shed by the fetus and AFP
- Provides neural tube defects, chromosomal abnormalities and other genetic defects
What are some arguments in favor of parental screening?
5
- Pursue potential interventions that may exist
- Being planning for a child with special needs
- Start addressing anticipated lifestyle changes
- Identify support groups and resources
- Make decisions about carrying child to term
What are some arguments against parental screening?
3
- parents should accept of results regardless of outcome
- Making decisions about carrying child to term is not an option due to personal, moral or religious reasons
- Testing may pose risk of harming developing baby
What is Phenylketonuria (PKU)?
- Babies cannot process phenylalanine
- can build up in blood stream causing brain damage and mental retardation
