Antenatal Care and Screening Flashcards
What are some important points to raise during pre-pregnancy counselling with a mother that has known medical problems?
- Want to try optimize health during pregnancy (eg. lower HbA1c)
- Stop / change any unsuitable medication (eg. ACE-I for hypertension)
- Advise regarding complications due to medical problem (effect on child / worsening of maternal disease in pregnancy)
- Advise against pregnancy? (eg. significant cardiac disease associated with maternal mortality)
Why is it important to ask about previous pregnancies during pre-pregnancy counselling?
Because you can preemptively deal with pregnancy issues or plan pregnancy accordingly:
- Pre-eclampsia: 150mg aspirin during pregnancy
- Previous caesarean section may opt for repeat caesarean
What are some important things to investigate during antenatal examination?
- Longitudinal or transverse lie of baby
- Fetal presentation: breech (foot or buttocks presenting instead of head) or vertex
- Listen to foetal heart
- Assess size of baby
When is screening for infection carried out during pregnancy? What are some commonly tested for pathogens?
During the 1st trimester
- Hepatitis B (can immunize baby if infected)
- Syphilis (penicillin)
- HIV (can attempt to reduce vertical transmission)
- MSSU (UTI)
- Rubella
What is isoimmunization? Give an example
The development of antibodies against blood groups
Eg. When a rhesus negative woman is carrying a rhesus positive baby & some of the baby’s blood cells make it into maternal circulation (miscarriage / haemorrhage) the mother produces anti-D antibodies
In subsequent pregnancies the anti-D antibodies can cross into the foetal circulation, destroy foetal blood cells and cause anaemia in the child
How can rhesus isoimmunization be treated? Who is treatment offered to?
Passive immunization can be provided which allows foetal RBC’s to be destroyed before the mother can provide an immune response to them
Offered to all Rh negative women prophylactically and after possible sensitizing events
When is screening done for iron deficiency anaemia and isoimmunization during pregnancy?
Performed in 1st trimester and at 28 weeks
What sort of anomalies does the first visit ultrasound scan test for? When is it performed?
Ideally performed between 11 & 14 weeks gestation
- Ensures viable pregnancy
- Multiple pregnancy?
- Identifies obvious abnormalities
What chromosomal abnormality characterizes down syndrome? What are some factors that may increase the risk of having a baby with downs?
3 copies of chromosome 21 (trisomy 21)
- Advanced maternal age at time of pregnancy and family history of chromosomal abnormality increases risk
What does a Nuchal translucency scan test for? When is it done?
Can detect some genetic abnormalities such as Downs syndrome
Done in first trimester
If Nuchal Translucency scan isn’t possible, what is another option for screening?
Second trimester biochemical screening
After initial screening tests are done, what are the net steps?
If the risk is > 1:150 further testing is offered
Eg: amniocentesis / CVS
What is a CVS test?
Chorionic villus sampling
Checks if baby has genetic or chromosomal conditions
How does the doctor determine whether to do a CVS or amniocentesis as part of further genetic testing? How safe are these procedures?
CVS - done between 10 & 14 weeks
Amniocentesis - done from 15 weeks onwards
CVS - 1-2% chance of miscarriage, Amnio - 1% chance
What is non-invasive prenatal testing?
Maternal blood taken and foetal cell free DNA examined
Checks for chromosomal abnormalities, further testing recommended if high risk
