Pregnancy Flashcards
Physiological changes in coagulation during pregnancy
Increase: fibrinogen, FVIII, VWF, VII, X
Stable: II, IX, XII
Slight fall: XI, XIII
Protein S falls (may be <40%), Protein C is stable
AT levels fall at time of delivery.
Acquired APC resistance due to high FV, FVIII and low protein S
Causes of anaemia in pregnancy
- Increased plasma volume
- Iron deficiency
- Folate deficiency
- AIHA - higher risk
Morphology changes in pregnancy
- May have increased MCV
- Neutrophilia
- Toxic changes
What are 5 reasons why VTE risk is higher in pregnancy?
- Increased clotting factors and fall in protein S
- Acquired APC resistance due to high factor V and VIIII levels
- Reduced fibrinolysis (increased PAI-2 from placenta)
- Compressive effect of placenta (2/3 DVTs occur in left leg)
- Operative delivery
- Inherited thrombophilia (seen in around 30%)
VWD in pregnancy
VWF and FVIII levels increase in pregnancy therefore may not have increased bleeding during pregnancy
BUT precipitous fall post partum ==> PPH
High molecular weight VWF does not increase therefore types 2A, 2B and 3 may have bleeding.
Replace with Biostate (dosing based on FVIII)
Haemophilia A and B in pregnancy
FVIII levels increase therefore haemophilia A is often not a problem
FIX levels are stable/don’t increase therefore haemophilia B carriers may need factor replacement when levels fall below 40%
Management of delivery in women who have haemophilia or severe VWD
- Confirm disorder and severity
- Preconception counselling
- Close monitoring during pregnancy, particularly 3rd trimester to allow for delivery plan.
- Assess risk to:
1. Mother
2. Fetus (sex determination is essential) - Avoid instrumental delivery if fetus might have VWD or haemophilia
- Biostate given for VWD, avoid DDAVP
- Avoid IM vitamin K to neonate if possible risk baby has haemophilia.
Methods to confirm fetal blood sample (5)
- MCV (fetal RBCs larger - occ unreliable if mother has macrocytosis or fetus has been transfused adult RBCs)
- BhCG - most reliable test, should be absent in fetal blood but high in maternal blood
- Apt and Downey (alkaline denaturation occurs with maternal blood but not fetal blood)
- Kleihauer Betke (acid denaturation of maternal cells but not fetal RBCs)
- I antigen - present on maternal cells but not fetal cells
Methods of intrauterine blood sampling
- Cordocentesis
- Intrahepatic vein sampling
- Cardiocentesis (high risk, last resort)
* *give steroids, perform close to theatre, experienced person
5 Features of Gestational Thrombocytopenia
- Onset during late 2nd/3rd trimester
- Mild to moderate thrombocytopenia (usually >80, rarely <50)
- Not present prior to pregnancy
- Resolves post partum
- No risk of neonatal thrombocytopenia
Features of ITP in pregnancy
- Usually onset earlier in pregnancy, progressively worsens
- May be difficult to treat
- Thrombocytopenia often more severe than gestational thrombocytopenia
- 15% risk of neonatal thrombocytopenia (nadir 2-5 days, usually resolves by 2 weeks, low risk of ICH, doesn’t correlate with maternal platelet count)
