Antenatal screening Flashcards
What history points are required in the booking appointment
- Obstetric history
- Medical and surgical history
- Medications and allergies
- Mental health
- Family history
- Social history
- History of domestic abuse or violence
- Safety
- History of FGM
What investigations are performed in the booking appointment
History
Weight
Height
Blood pressure
What are some important mental health questions asked in the booking appointment
- Any new feelings that make you anxious or disturbed?
- Suicide or self harm?
- Feelings of incompetency as a mother?
- Feeling estranged from the baby?
What are the criteria for oral glucose tolerance testing in pregnancy
- BMI > 30
- Previous macrosomic baby >4.5kg
- Family history of diabetes (1st relative)
- History of PCOS
- Ethnic family origin from area of high diabetes prevalence
What are the main screening tests offered during pregnancy
- Infection
- Anaemia
- Rhesus status
- Haemoglobinopathy
- Down’s, Edward’s and Patau’s syndrome
- Foetal anomalies
What is involved in antenatal infection screening
- Urine - Mid-stream urine sent
- Blood - HIV, Syphilis, Hepatitis B
When is anaemia screening performed in pregnancy
FBC at booking scan and 28 weeks
What are the 2 conditions screened for in haemoglobinopathy screening
Sickle-cell disease
Thalassaemia
What is involved in haemoglobinopathy screening
Family origin questionnaire
Blood tests
When is rhesus antibody screening performed in pregnancy
Blood grouping at booking and 28 weeks
What is done if the mother is found to be rhesus D-negative
- Offer anti-D to prevent maternal antibody formation
- Routine prophylaxis at 28 weeks
- Additional anti-D for potentially sensitising events
Describe the levels of trisomy screening in pregnancy
- Quadruple screening
If high risk on 1. then:
- NIPT
If high risk on 2. then:
- Invasive foetal genetic testing (CVS or amniocentesis)
What is used in the quadruple trisomy screen?
Crown-Rump length
Nuchal translucency
HCG levels
PAPP-A levels
What is nuchal translucency
The thickness of fluid behind a babies neck
When is quadruple trisomy screening done in pregnancy
11 - 13+6 weeks
What is a normal NT value (If CRL is 45-84mm)?
<3.5mm
What are some reasons why NT may not be measured?
- User error (Very specific measurement)
- Baby too small
- Baby in an unsuitable position
What are the risks of higher NT values
When is 2nd trimester trisomy screening offered?
If booking was too late for 1st trimester screening
If NT was not obtained during 1st trimester
What is screened for in 1st trimester trisomy screening
Trisomy 13 - Patau’s syndrome
Trisomy 18 - Edward’s syndrome
Trisomy 21 - Down’s syndrome
What is screened for in 2nd semester trisomy screening
Trisomy 21 - Down’s syndrome
What tests are done in 2nd trimester trisomy screening
HCG and AFP
When is 2nd trimester trisomy screening performed
15-20 weeks
What risk of trisomy is considered high risk
1/150 chance
What is the risk scale on trisomy screening
1/5000 - 1/2
What does NIPT stand for
Non-invasive prenatal testing
What is involved in NIPT
Maternal blood sample to detect cell free foetal DNA from the placenta
What are the 2 main forms of invasive foetal genetic testing
Chorionic villous sampling (CVS)
Amniocentesis
When is CVS performed
11-14 weeks
When is amniocentesis performed?
> 15 weeks
What is the miscarriage rate of CVS
<2%
What is the miscarriage rate of Amniocentesis
<1%
Is local anaesthetic required in invasive foetal genetic testing
CVS - Local anaesthetic
Amniocentesis - No anaesthetic
When is the mid-trimester anomaly screening performed?
18 - 20+6 weeks
What are the benefits of the foetal anomaly screening programme (FASP)
Reduces mortality and morbidity and may allow in-utero management
What 11 conditions are screened for on the FASP scan
- Anencephaly
- Open spina bifida
- Cleft lip
- Diaphragmatic hernia
- Gastroschisis
- Exomphalos
- Serious cardiac abnormalities
- Bilateral renal agenesis
- Lethal skeletal dysplasia
- Edward’s syndrome (T18)
- Patau’s syndrome (T13)
What is open spina bifida
A congenital condition in which there is failure of the neural tube to close, meaning the spinal cord comes outside of the foetal spine in a sac
What is gastroschisis
A birth defect where there is a hole in the abdominal (belly) wall beside the belly button. This results in the baby’s intestines extending outside of the baby’s body. Sometimes other organs, such as the stomach and liver, can be found outside of the baby’s body.
