Screening Flashcards
What 4 tests are done at the booking test?
- Take a history of the mother (medical, obstertric, surgical etc.)
- Examination
- Blood tests
- Ultrasound
When is the booking test done?
Between 8 and 12 weeks with the midwife
What is Naegele’s Rule?
The estimated due date based on the onset of the woman’s last menstrual period. Add on 9 months and 7 days- 280 days- to arrive at the due date
This is used up until scan is performed
What must be seen before you confirm the pregnancy as viable?
Foetal heart beat
What does this ultrasound show and what is it a sign for?
Empty gestational sac
Must rule out ectopic pregnancy
What does this US show?
Dichorionic twins
If the woman is late in arranging her booking scan, what is used to measure the gestational age and estimated delivery date?
Foetal head is measured
In a normal low risk pregnancy, what 2 scans does a woman get offered?
Booking scan (8-12 weeks)
Anomaly scan to check for abnormalities
In an antenatal appointment, which 2 things are covered in the history?
Physical and mental health of the mother
Foetal movements
What is placenta praevia?
Occurs when the placenta is low lying in the uterus and covers part of the cervix. Placenta site is identified at anomoly scan.
What is Trisomy 21?
Downs Syndrome
What is Trisomy 18?
Edward’s Syndrome
What is trisomy 13?
Patau’s Syndrome
What is NIPT?
Non-Invasive Prenatal Testing
Blood test taken from the mother in pregnancy that uses DNA technology to evaluate the chance that the baby has of having a certain choromosomal condition
Offered if there is a high chance of trisomy as a secondary screening test
What is CRL?
Crown Rump Length
Length of the embryo/foetus from top of its head to bottom of its torso
Most accurate estimation of gestational age in early pregnancy
What is amniocentesis?
Test for chromosomal abnormalitis
A small amount of amniotic fluid which contains fetal tissues is sampled from the amniotic sac.
When is amniocentesis usually performed?
Usually after 15 weeks
What is chorionic villus sampling?
A prenatal test to detect birth defects and genetic disease in the fetus.
Small sample of the chorionic villi is taken from the placenta to be further analysed usually through FISH or PCR
When is chorionic villus sampling usually carried out?
After 12 weeks
What are the major haemoglobin disorders screened for?
Sickle cell anaemia
Thalassemias
Why is it important to find out the woman’s blood group and rhesus status?
- If transfusion is need- needs matched for antibodies
- Some red cell antibodies can cause fetal anemia- a treatable and identifiable condition
- Anti-D injections can be given to prevent D antigens forming in Rh negative women
In a rhesus negative women, when would anti-D injections be given?
- Routinely from 28 weeks
- Given after any sensitising event (invasive procedure, termination of pregnancy, antepartum haemorrhage)
- Given again after birth if baby is rhesus positive
- Cord blood is tested
What are some of the risk factors for gestational diabetes?
- BMI above 30
- Previous macrosomic baby weighing 4.5kg or above
- Previous gestational diabetes
- FH of diabetes
- Minority ethic family origin with high prevelence of diabetes
What test is done if a woman has risk factors for developing gestational diabetes?
OGTT
When would ultrasound be used to measure fetal size instead of SFH?
- If woman has a single SFH which plots below the 10th centile or serial measurements which demonstrate slow or static growth by crossing centiles
- Women in whom SFH measurement may be inaccurate- BMI over 35, large fibroids, hydramnios
How much aspirin should women at high risk of pre-eclampsia take?
150mg daily, from week 12 to week 36
What are some of the high risk factors for developing pre-eclampsia?
- Hypertensive disease during a previous pregnancy
- CKD
- Autoimmune disease such as SLE or antiphospholipid syndrome
- Type 1 or Type 2 DM
- Chronic hypertension
What are some of the factors that indicate a moderate risk for pre-eclampsia?
- 1st pregnancy
- Age 40+
- Pregnancy interval of more than 10 years
- BMI of 35 or more at first visit
- Family history of pre-eclampsia
- Multiple pregnancy
If a woman has more than 1 moderate risk factor for developing pre-eclampsia, how much aspirin should they take?
75mg daily from 12 weeks till the birth
When is the anomoly scan done?
A= 12 weeks
B= 20 weeks
C= 28 weeks
20 weeks
Around 12 weeks is the booking scan and at 28 weeks the woman has blood taken to check for anaemia and red cell antibodies
