Pregnancy Tutorial Flashcards
What is the purpose of an early pregnancy scan?
Viable pregnancy
Multiple pregnancies
Intrauterine
Gestational age; CRL (if over 12 weeks; use head circumference)
Placental position
Any obvious anomalies (anencephaly, gastroschisis, limb defects, major heart anomalies)
What is the gestation of 6.64cm CRL?
12 + 2 weeks
How is the robustness of a screening test assessed?
Specificity (true positive / (true + false neg)
Sensitivity (true neg / (true + false pos)
What are the constituent components involved in 1st trim screening for down syndrome?
bhCG + PAPP-A
NT
Maternal age (>40)
What is nuchal translucency?
Measure of thickness behind frontal neck - fluid
From what gestation is NT valid?
11- 13 + 6 weeks
1st trim
What is considered a normal NT?
<3.5mm
Reasons for increased NT?
Chromosomal abnormalities; T 18, 21
Cardiac abnormalities
Turner’s syndrome
What is MSAFP?
Maternal serum AFP -
In what conditions is an increased MSAFP seen?
Multiple pregnancies Placental abruption Anencephaly Spina bifida Gastroschisis
What is pre-eclampsia?
Pregnancy-induced hypertension (>20 wks) in association with proteinuria (>0.3 g in 24 hours) with or without oedema
What is the pathogenesis of pre-eclampsia?
Suboptimal uteroplacental perfusion associated with a maternal inflammatory response and maternal vascular endothelial dysfunction. This in turn leads to vascular hyperpermeability, thrombophilia and hypertension, which may compensate for the reduced flow in the uterine arteries
What are the parameters for hypertension in pregnancy?
Systolic BP >140 mm Hg or diastolic BP >90 mm Hg
What is HELLP syndrome?
Haemolysis
Elevated liver enzymes
Low Platelets
Mode of action of labetalol?
Alpha and beta blocker
Mode of action of betamethasone in neonate?
Increase lung maturity (surfactant production)
Decreased NEC
Decreased intraventricular haemorrhage
Mode of action of hydralazine?
Peripheral vasodilatory via direction relaxation of vascular smooth muscle
Mode of action of magnesium sulfate?
Peripheral and cerebral vasodilator
Anticonvulsant
Membrane stabiliser
What is meant by rhesus neg?
No D antigens on the RBC of mother
What is the mode of action of anti-D?
Neutralises foetal antigens in maternal blood to prevent mother isoimmunization resulting in the production anti-D antibodies which can have catastrophic effects on future pregnancies and on neonate
What is seen in the blood of a sensitized mother?
Positive antibodies to D antigen
In an affected rhesus positive baby, what would happen to the following cord blood parameters:
Hb
Bilirubin
Coombs test
Hb; decreased
Bilirubin; increased
Coombs test; positive (detects Abs that act against the surface of RBC)
When should anti-D be given to prevent rhesus isoimmunisation following a sensitizing event?
Ideally within 72 hours
But up to 10 days
What route is anti-D given?
IM
How does the dose of anti-D differ based on gestational age?
<20 wks; 250 IU
>20 wks; 500 IU
List some sensitizing events that warrant anti-D?
Post-partum; within 24 hours of a birth of Rh +ve baby Miscarriage >12 weeks ToP at any gestation Amniocentesis Trauma to abdomen
When is routine prophylaxis given to Rh -ve women?
28 weeks; dose of 500 IU IM
Would you administer anti-D in this case: Rh -ve mother ABO compatible Rh +ve baby Coombs test -ve Infant bilirubin level normal
Yes; give postpartum to prevent isoimmunisation
Would you administer anti-D in this case: Rh -ve mother ABO incompatible Rh -ve baby Coombs test -ve Infant bilirubin level normal
No
Would you administer anti-D in this case: Rh -ve mother ABO compatible Rh + baby Coombs test +ve Infant bilirubin level increased
Yes and no
Mother already sensitized so anti-d antibodies already formed
Need to monitor future pregnancies very carefully to assess foetus for anaemia and hydrops
Would you administer anti-D in this case: Rh +ve mother ABO incompatible Rh -ve baby Coombs test +ve Infant bilirubin level increased
No; infant increased bilirubin due to ABO incompatibility not rhesus
Monitor baby; keep hydrated
Can offer phototherapy for jaundice
What are routine components of antenatal care routine?
Weeks pregnant Height of uterus/ fundal height BP Urinalysis Oedema Fifths palpase Foetal lie and presentation FHR Foetal movements FBC
What changes occur normally in the maternal CV system?
Increased CO
Increased HR
Decreased BP in 2nd trim
