Clinical Aspects of O+G Flashcards
What form of imaging is predominantly used in O+G?
US
Evaluate the different imaging modalities which may be used in pregnancy.
• X-Ray
- Away from pelvis, negligible
- Avoid radiation of breast tissue and uterus
• MR
- No evidence of harm
• CT (+ CTPA)
- Increased risk (10%) of breast cancer
- Relative risk is 1.1x
• V:Q Scan
- No established risk
- Lower sensitivity and specificity cf CTPA
• US
- No direct harm
- False positive risks e.g. ovarian cysts of unknown significance anxiety or unnecessary intervention
State 3 things which may be looked for when ultrasound scanning the uterus.
• Uterine anomalies – bicornuate uterus
• Uterine tumours – fibroids
• Cervix – length predictor for onset of labour
- Important if premature/late miscarriage
• Uterine artery blood supply – predictor for pre-eclampsia
State 5 things a healthcare worker may be looking for when imaging a foetus with ultrasound.
- ‘Alive’ or not
- Location: IU/Ectopic
- Size of foetus (Crown-Rump Length – CRL)
- Number of foetuses and type
- Anatomical structures
• Foetal anomaly screening (18-21 weeks): head/cerebral hemispheres/lateral ventricles/cerebellum/foetal face/limbs/hands/feet/diaphragm/kidneys and bladder/spine
• Growth: Abdominal and head circumference/femur length + Estimated foetal weight
• Wellbeing: Liquor volume and Foetal blood flow measurements (blood flow; absent flow in diastole ≈ high placental resistance)
- Can check Middle Cerebral Artery (foetal anaemia or hypoxia) or Ductus Venosus (reversal of wave form in pre-terminal hypoxia)
• Presentation (cephalic vs breech or transverse vs oblique)
• Position of head in labour (e.g. if occiputs transverse before using forceps)
Describe antenatal care.
Medical care provided to detect and manage pre-existing maternal/foetal disorders that may affect the pregnancy or foetal wellbeing.
Outline what is done at an antenatal booking visit.
- Full history, full examination
- Fundal height should be taken (cm)
- Blood tests: ABO, Rhesus, STI screening, HBV, HCV, ßhCG and PAPP-A
- Early pregnancy US scan: viability, number of foetuses, gestation, nuchal translucency
Which blood tests are conducted at the booking visit?
• Blood tests: ABO, Rhesus, STI screening, HBV, HCV, ßhCG and PAPP-A
What does the early pregnancy scan look at?
viability, number of foetuses, gestation, nuchal translucency
When is the booking visit scheduled for?
12/40
Upon follow-up visits, what is conducted?
- Full history, full examination
- Fundal height should be taken (cm), Liqor volume, foetal lie, presentation, foetal HR
- Mid-pregnancy scan (20 weeks): microencephaly, short limbs, brain anomalies, cardiac anomalies; placental position
- Quadruple blood tests: ßhCG, AFP, inhibin-A, unconjugated estriol (uE3)
When is the Quadruple test scheduled for?
around 20 weeks
What does the Quadruple test assess?
uE3
AFP
ßhCG
Inhibin-A
When is the mid-pregnancy scan indicated?
• Mid-pregnancy scan (20 weeks): microencephaly, short limbs, brain anomalies, cardiac anomalies; placental position
What does the mid-pregnancy scan look for?
microencephaly, short limbs, brain anomalies, cardiac anomalies; placental position
Most are seen after 20 weeks however cardiac abnormalities are seen after 12 weeks
What is the risk threshold for investigating the risk of Down Syndrome in a foetus.
1 in 250
Describe CVS and the risks.
= Removal of chorionic villi cells from placenta to genetically analyse (12 weeks onwards)
- Miscarriage rate of 2% (2/100)
Describe Amniocentesis and the risks.
Removal of amniotic fluid from the uterus to genetically analyse cells (15 weeks onwards)
- Miscarriage rate of 1% (1/100)
Describe pre-implantation genetic diagnosis.
Genetic test using FISH on embryo prior to re-implanting. This requires ART such as IVF.
Evaluate the benefits and drawbacks of PIGD.
Benefits:
- Assurance
- Less likely to require TOP
Drawbacks:
- Invasive
- Costly
- Risk of multiparity
State the indications for PIGD.
- Parental chromosomal abnormality
- Robertsonian translocation
- Reciprocal translocation
- X-linked disorders
- Genetic disorders
List 3 principles of safe prescribing in pregnancy
- Establish exposure to medication: exposure; gestational age; PMHx; FHx; Check drug information; Background risk
- Intended continuation/initiation of medication: Benefits > costs; try to avoid 1/3 use; Use drugs known in pregnancy; Absence of data ≠ safety
- ICE and pre-conception planning/first consultation/background screening + check
List 3 drugs you should not prescribe when breastfeeding.
MTX Cyclophosphamide Lithium Metronidazole Chloramphenicol Aminoglycosie
What if foetotoxicity?
toxic functional damage occurring with exposure to medication in later pregnancy
What is teratotoxicty?
potential for drug cause foetal malformations affecting embryo 3-8 weeks after conception
