Antenatal testing Flashcards
What are some important things to cover in prenatal health education?
- Health education
- Weight, age
- Diet
- Vaccinations
- Activity/exercise
- Alcohol/ drugs
What is antenatal testing?
- Health education
- Antenatal examination
- General and obstetric testing
- Dating scan (10-11 wks) , anomaly scan (@19 weeks)
- Screening
- Biochemical/combined scan
- Lab investigations
- Glucose screen, vaccinations, known disease
- Health education
TORCHES
What are the 5 infections that pregnant women need to be vaccinated against?
TORCHES:
-Toxoplasmosis
- Others (syphillis, hep B)
- Rubella
- Cytomegalovitus (CMV)
- Herpes Simplex/ HIV
What is Down’s syndrome?
- Congenital disorder dues to trisomy of chromosome 21 - additional copy
- Prior to or at conception, a pair od 21st chromosomes in either the sperm or the egg fails to separate. As the embryo develops , the extra chromosome is replicated in every cell of the bofy
- An increase in risk with maternal age but >90% pregnancies occur in women under 35 therefore screening needed for the large low risk population
How do you test for Downs syndrome?
- No way of testing definitively for DS before prehnancy
- Amniocentesis not suitable for mass screening
- The combined test (combines ultrasound anf biochemical markers with maternal age)
- Biochemical- maternal serum levels of pregnancy associated plasma protein-A (PAPP-A) serum and free Beta hCG.
- Ultrasound is nuchal translucency
- In pregnancies with down’s PAPP-A usually low while Beta hCG is raised
- Carried out between 10-13 weeks of pregnancy
What is the nuchal translucency test?
What does the nuchal translucency test for?
The nuchal translucency test measures the nuchal fold thickness. This is an area of tissue at the back of an unborn baby’s neck. Measuring this thickness helps assess the risk for Down syndrome and other genetic problems in the baby.
What are Diagnostic Tests - Amnio vs CVS
Amniocentesis
Amniocentesis
Diagnostic Tests -Amnio vs CVS
Chrionic villus sampling
Amniotic fluid
Fluid removed by ulatrasound-guided needle
inserted into uterus
Only a small amount of amniotic fluid is
required
Applicable to a wide range of pregnancies (12 to 34 weeks)
Definitive results by qPCR within 24 h
90 - 100% accurate in the detection of major
autosomal trisomies
* Trisomy 21 (Down’s syndrome)
* Trisomy 18 (Edwards syndrom)
* Trisomy 13 (Patau syndrom)
Sex chromosome aneuploidy
* 11-14 weeks
Chorionic villi sample removed from developing placenta (tran abdominally or transcervically under US control).
Fetal cells sampled from the placenta
Result reported in —3 days
Rapid decision-making if condition
identified
What are antenatal screening advantages?
- Earlier screening in 1st trimester is an advantage
( If HIV positive, or have Hep B or C positive, CVS or amniocentesis might increase the
risk of passing these on to the baby. ) - Information earlier, more options for parents
Reduced number of invasive procedures
May detect other anomalies (or risk for) at time of scan and increased risk of - Adverse pregnancy outcome—referral for 2nd
trimester
Good time to date pregnancy accurately
What are the haemolytic diseases of the newborn?
- Red blood cells of the foetus/ newborn attacked by maternally-derived antibodies
- Maternal antibodies produced as a direct result of a blood group incompatibility between the mother and foetus with ans directed against the Rh antigen on fetal erythrocytes
- If a blood group is Rh (rhesus) negative, an inhection of anti-D immunoglobulin to prevent you from developing antibodies against your baby’s blodo cells in future pregnancies.
What happens when a father is Rh positive and the mother is Rh negative?
- Rh positive father = one copy of RhD gene
- 1/2 children Rh Positive
- 1/2 children Rh Negative
- Two copies of RhD gene = ALL children Rh Positive
