Antenatal Care - High Risk Pregnancy Flashcards
What are the two main options for diagnostic testing for foetal abnormalities?
Chorionic villus sampling (CVS)
Amniocentesis
When can CVS be done?
Between 11 and 13+6 weeks
What can amniocentesis be done?
After 15 weeks
What are the risks associated with diagnostic tests?
Miscarriage
- 2% for CVS
- 1% for amniocentesis
Also risk of amniotic fluid embolism with CVS
When are diagnostic tests offered to women?
If she is considered to be at increased risk of foetus having a genetic syndrome e.g.
- high risk at Down’s screening
- abnormality at foetal anomaly scan
- known genetic condition in mother or father
Which other screening test is available for genetic conditions, but not on the NHS?
Non-invasive prenatal testing (NIPT)
- analyses foetal DNA in mother’s blood
What is the benefit of NIPT?
More sensitive than 1st trimester down’s screening
–> reduces number of false positives, therefore reduces number of women undergoing CVS or amniocentesis
What are the risk factors for multiple pregnancy?
Assisted conception Ethnicity (African) Family history on maternal side Increasing maternal age Increasing parity Tall women > short women
How is zygosity described in multiple pregnancy?
Monozygotic - splitting of a single fertilised egg
Dizygotic - fertilisation of 2 ova by 2 sperm
How is Chorionicity described in multiple pregnancy?
(1 placenta or 2 placentas)
Dichorionic - always dichorionic diamniotic Monochorionic: - monochorionic monoamniotic - monochorionic diamniotic conjoined twins
Which type of twins are at the highest risk of complications?
Monochorionic/monozygous twins
–> twin-twin transfusion syndrome
What are the signs and symptoms of multiple pregnancy?
Exaggerated pregnancy symptoms e.g. sickness/hyperemesis gravidarum
High AFP
Large for dates uterus
Multiple fetal poles
How is antenatal care different for multiple pregnancy?
Consultant led care
Every 2 weeks for monochorionic pregnancy, every 4 weeks for dichorionic pregnancy
Iron + folic acid supplements
Low dose aspirin to prevent hypertensive disorders
From 16th week, USS every 2 weeks
What is twin-twin transfusion syndrome (TTTS)?
Disproportionate blood supply to foetuses in monochorionic pregnancies
- donor twin has reduced blood supply
- recipient twin has increased blood supply
What are the features of the donor twin in TTTS?
Reduced growth + development
Decreased urine output –> anaemia + oligohydramnios
What are the features of the recipient twin in TTTS?
Increased urinary output –> polyhydramnios, polycythaemia + eventually heart failure
How is TTTS treated?
Fetoscopic laser ablation recommended before 26 weeks
When would a C-section be planned for multiple pregnancy?
Triplets or more
Monochorionic monoamniotic twins
Other twins - mother’s choice
What are the options for delivery of a baby in breech position?
Vaginal/external cephalic version
or Elective C-section
(maternal choice)
When would external cephalic version be offered for breech presentation?
At/after 36 weeks
breech is normal up to 36 weeks
When is a pregnancy considered ‘prolonged’?
After 42 weeks
What are the risks of prolonged pregnancy?
Increased risk of stillbirth
Meconium aspiration –> respiratory distress
When is induction of labour offered to prevent prolonged pregnancy?
Between 41-42 weeks
How is a pregnancy dated during the first trimester (usually booking visit)?
Crown-rump length on USS
How is foetal growth assessed during the third trimester?
Abdominal circumference, head circumference + femur length
–> equation calculated an estimated foetal weight
Which scans are safe during pregnancy?
USS
MRI
How many scans does an uncomplicated pregnancy usually get?
2
- booking + anomaly
- foetal growth scans only done in high risk pregnancies
How is foetal growth monitored in low risk pregnancies?
Symphyseal fundal height (SFH)
- if too large or small, referred for a growth scan
What is the definition of stillbirth?
Baby born with no signs of life at or after 28 weeks gestation
What are the definitions of neonatal mortality, early neonatal mortality + later neonatal mortality?
Noeonatal mortality: - death of a live born baby within 28 days of life Early: - death within 7 days Late: - death after 7 days, before 28 days
