Genetics

1. Amniotic Fluid Test
Amniocentesis

2. Amnion;
 A membrane that closely covers
the embryo when first formed.
 It fills with the amniotic fluid which causes
the amnion to expand and become
the amniotic sac which serves to provide a
protective environment for the developing
embryo or fetus.

3. What is amniocentesis?
 A prenatal procedure that is performed in
order to remove and examine fluid from the
amniotic sac that surrounds the developing
fetus.
 An ultrasound is used to determine a safe
spot for the insertion of the needle.
 Fluid is sent to laboratory for analysis and
detection of chromosomal abnormalities, as
well as fetus lungs maturity

4. Needs for Amniocentesis;
 Based on the developing fetus.
 Amniocentesis determines abnormalities in
gene pairing.
 Assesses the maturity of the baby’s lungs.
 Diagnose or rule out a uterine infection.
 Checks the health of the developing fetus,
including blood sensitization (blood RH)
mixing of parent and fetus blood.

5. How is it performed?
 A needle is inserted into mothers abdomen.
 A small amount of fluid(20 ml) which contains
fetal tissues is sampled from the amniotic sac.
 After centrifugation fetal cells are separated.
(sex determination and DNA analysis).
 Growth for weeks in culture medium to detect
metabolic disorders.
 Most common abnormalities detected are
Down syndrome.

6. Amniocentesis Benefits;
 Informs expecting parents of the possible
chromosomal abnormalities within 15-25
weeks of pregnancy.
 Detects the following gene abnormalities:
– Mental retardation
– Down Syndrome ( Trisomy 21, three copies
of the chromosome)
– Turners Syndrome (absence of sex
chromosome X)

7. – Klienfelters (XXY)
– Cystic Fibrosis ( Mucus membranes cloud
lungs, chronic lung disease.)
– Sickle Cell Disease (Hemoglobin S) (
crescent shaped blood cells deliver less
oxygen to bodies tissue)
– Cleft palate.

8. Amniocentesis Risks;
 Increased risk factors:
– Obesity
– Previous abdominal surgery.
 Possible complications include:
– Miscarriage ( Less than 1% chance)
– Bleeding, cramping, and leaking of vaginal
fluids.
– Infection.
– Harm to the fetus from needle penetration.
– Blood mixing.