Pre-natal Tests Flashcards
What are prenatal tests?
Prenatal tests can assess the health and development of a baby during pregnancy.
→ Prenatal screening tests cannot tell if the baby has a genetic condition but they might be a good indicator to further testing that may be considered
↪ Usually low risk as they are non invasive.
↪ Includes Ultrasound, NIPT and Nuchal Screening
→ Prenatal Diagnostic tests are test that can assess the chromosomes of a baby and detect variations in chromosome or single gene (So can detect genetic disease with really high accuracy).
↪ Does not check for every possible problem
↪ Risk of miscarriage is involved.
Prenatal Tests: Ultrasound
→ Done when baby is 8-12 weeks
→ Uses harmless sound waves to create images of developing baby in uterus
→ Can confirm how much pregnancy has progressed, whether there is more than one baby and the position of the baby and the placenta
Placenta
An organ that develops during pregnancy and is attached to the wall of the uterus. The umbilical cord connects the placenta to the baby.
→ It provides oxygen and nutrients to a growing baby
→ It removes waste products from a baby’s blood.
Prenatal Tests: Non-Invasive Prenatal Testing (NIPT)
→ Can be done when the baby is 10 weeks or older
→ A sample of the mothers blood is taken as during pregnancy some of the DNA from the baby crosses into the mother’s bloodstream.
→ Can check for down syndrome and other chromosome conditions but, it can only estimate the risk of the conditions has the fetal and maternal DNA are mixed in a genetic material called cfDNA
Prenatal Tests: Nuchal Translucency
→ Can be done when the baby is 11.5-13.5 weeks old
→ Nuchal Translucency is the collection of fluid under the skin of the baby’s neck. A specialized ultrasound scan measures the amount and estimates the chance of the baby of the chromosome syndrome like down. Some times a blood test is involved
↪ Identifies 75-90% of babies with down syndrome
Prenatal Tests: Amniocentesis
→ Can be done when baby is 15-19 weeks old
→ Chromosomes are examined from the amniotic fluid that surrounds the baby in the uterus and contains cells from the baby
↪ Using ultrasound a needle is used to extract the fluid
→ Used to check from trisomy 18 or trisomy 21 are present
→ Increased risk of miscarriage.
Prenatal Tests: Chronic Villus Sampling
→ Can be done when the baby is 11-13 weeks old
→ Small piece of tissue is removed from the chorion (Apart of placenta and responsible for diffusing oxygen and nutrients).
↪ Needle is either inserted through the abdomen or vagina
→ It is done to confirm the presence of trisomy 18 or 21
→ Increased risk of miscarriage and baby limb deformity