Antenatal Screening Flashcards
What antenatal tests are usually done?
ABO; Rhesus
Syphilis; Rubella; HIV; Hep B&C;
Urinalysis; MSSU C&S
Ultrasound
What does ultrasound look for?
Confirm viability
Number of fetuses
Confirm gestation
In the first trimester, what can be used to look for Down’s risk?
Measure of skin thickness behind fetal neck using ultrasound (Nuchal thickness; NT)
In the second trimester, what can be used to look for Down’s risk?
Blood sample at 15-20 weeks
Assay of HCG and AFP
What would be a high level of risk of Down’s, needing further investigation e.g. amniocentesis
1/250
When is amniocentesis normally performed, and what is the miscarriage rate?
after 15 weeks
Carries a miscarriage rate of 1%
When is chorionic villus sampling normally performed, and what is the miscarriage rate?
Usually performed after 12 weeks
Carries a miscarriage rate of 2%
What does amniocentesis take cells from?
skin/hair
What does chorionic villus sampling take cells from?
placenta
What characterizes Trisomy 18 (Edward’s syndrome)?
IUGR
Single umbilical artery
overlapping clenched fists
Rockerbottom feet
What BMI may cause a pre term birth?
What drug may be particularly causative of pre term birth?
cocaine
What age group are prone to pre term birth?
teenagers
What twins are at a higher risk of pregnancy complications?
monochorionic/monozygous
How can you tell chorionicity before birth?
shape and thickness of membrane
