3. antenatal screening Flashcards
what are 3 downsides to screening
- false positives
- harm from screening or further tests
- cost
what is FPR
false-positive ratio
The ratio of patients who are disease-free but test positive for an illness, as a result of error, to all patients who do not have the disease
what theory is used to estimate the probability of a diagnosis, given the appearance of specific signs, symptoms, or test outcomes.
bayes theorem
sickle cell and thalassaemia:
who gets screened, when and how is it done?
- pregnant women (also based on ethnic origin)
- pre-conception to 10 weeks
- blood test
if a pregnant woman tests positive for sick cell/thalassaemia:
what prenatal diagnosis is used?
CVS (Chorionic villus sampling)
amniocentesis
if a pregnant woman tests positive for sick cell/thalassaemia:
what would happen if the fetus is affected
termination
early specialist care
infectious disease:
-who gets screened and when does it happen
all women
at booking
infectious disease screening:
what gets screened for and how
HIV, Hep B syphilis
serology (diagnostic examination of blood serum)
what are the next steps if tested positive for HIV?
- maternal treatment
- high risk antenatal care
- prevent transmission to neonate
what are the next steps if tested positive for Hep B
- change antenatal care prevent transmission
- neonate receives vaccine
what are the next steps if tested positive for syphilis
maternal treatment to prevent congenital syphilis
chromosomal abnormalities:
- who gets screened
- when does it happen
all preg woman
between 11+0-13+6
chromosomal abnormalities:
how is screening performed
combined test:
- fetal nuchal translucency (fluid @ back of neck)
- maternal serum - beta-hCG and PAPP_A
how is the risk of trisomy 21 increased
with maternal age
what BRAIN abnormalities can be detected by US
acrania
holoprosencephaly
