O&G Written - Antenatal care Flashcards
Ways to estimate EDD?
Nagle’s rule: LMP - 3 months + 7 days + 1 year
- if cycle >28 days, add on the no. of days
- opposite if cycle <28 days
USS
- 11-13+6 week using Crown-rump length
- 14-20 weeks using head circumference
Routine booking IX
Urine dip + culture FBC Antibody screen Syphillis serology Rubella IgG HIV + Hep B testing offered USS \+/- Hb electrophoresis
Folic acid supplementation advice
Should be started pre-conception + continued until 12 weeks gestation
Normally take 0.4mg/day
High risk take 5mg
- BMI > 30
- diabetes
- sickle cell disease
- malabsorption
- anti-epileptic medication
Vitamin D supplementation advice
10 ug (400 units) for all women
25ug for high risk:
- BMI >30
- South Asian or Afro-Caribbean
- Low sunlight exposure
- Increased risk pre-eclampsia
Role of 20 week USS
identify foetal abnormalities e.g., cardiac or renal defect
+/- cervical length assessment to identify pregnancy at risk of pre-term delivery
+/- uterine artery resistance measurement to identify at risk of growth restriction + pre-eclampsia
Anti-D administration timeline
1st dose at 28 weeks
2nd dose at 34 weeks
Combined test components
Nuchal translucency
b-hCG
PAPP-A
+ maternal age
What does combined test screen for?
Trisomy 21 (Down’s syndrome)
+ Edwards (Tri18), Patau (Tri13)
Components of triple & quadruple test?
Beta-hCG
Unconjugated oestradiol
Alpha feto protein
+ Inhibin A in quadruple
possible in utero therapies
Anti-arrythmic ddrugs - flecainide, digoxin
NSAIDs for polyhydramnios
Laswer tx for twin-twin transfusion syndrome
Amnioreduction for polyhydramnios
Pleuroamniotic shunt for hydros / effusions
Vesicoamniotic shunt for urethral valve
Blood & platelet transfusion
Tracheal occlusion for diaphragmatic hernia (stimulates lung growth)
Valvoplasty for critical aortic stenosis
Cord occlusion for mono chorionic twins
Open NTD surgery
Timing of amniocentesis
Done from 15-20 weeks
Timing of chorionic villus sampling
Between 11-13+6 (10-15 weeks)
Technically can be done up until end of pregnancy
Miscarriage rate in invasive diagnostic testing
Amniocentesis = 1%
Chorionic villus sampling may be slightly higher but is done earlier when baseline spontaneous miscarriages are more common
Cut off for high risk of Down’s syndrome in Combined test?
> 1 in 150
Go on to have non invasive cell free foetal DNA +/- invasive diagnostic testing