Haematology 11: Obstetric Haematology Flashcards
Why are pregnant women anaemic despite an average Red cell mass increase of 120-130% ?
Plasma volume increases by 150% causing a net dilution
What is the WHO recommended daily Iron and folate supplementation for pregnant women ?
60mg iron
400mcg folate
What are pregnant women with thrombocytopenia at risk of when receiving epidural anaesthesia?
Spinal haematoma
What happens to platelets in pregnancy ?
They become larger
They are sometimes counted as RBCs by the FBC machine
List 4 causes of thrombocytopenia in pregnancy ?
Gestational thrombocytopenia (physiological)
Placenta praevia
ITP
MAHA
List 4 causes of MAHA ?
TTP- thrombotic Thrombocytopaenia purpura
HUS- Haemolytic uraemic syndrome
HELLP - haemolysis elevated liver enzymes and low platelets
Pre eclampsia
Why does pregnancy induce a net procoagulant state ?
To rapidly control bleeding at the placental site after delivery
Which anticoagulant factor falls to half the normal level during pregnancy ?
Protein S
Which coagulation factors increase the most during pregnancy ?
Factor VIII and vWF (3-5 fold)
Other factors that increase: Fibrinogen (2 fold) and factor VII (0.5 fold)
Which antifibrolytic factors increase during pregnancy ?
PAI-1 and 2
Which antifibrinolytic factor is produced by the placenta during pregnancy ?
PAI-2
During pregnancy the body assumes a ……….coagulant and ………… fibrinolytic state
Hypercoagulant
Hypofibrinolytic
Is D-dimer useful for exclusion of DVT in pregnancy ?
No
D-dimer is physiologically elevated in pregnancy
Which autoantibody is present in APLS ?
Anti-cardiolipin antibodies
Which 2 medications are recommended in APLS ?
LMWH + aspirin
Give 3 indications for testing for APLS ?
- 3 or more consecutive miscarriages <10 weeks gestation
- 1 morphological normal foetal loss > 10 weeks gestation
- 1 or more preterm births before 34 weeks gestation thought to be due to placental disease
What is placenta accreta ?
When the placenta goes through the endometrial lining (becomes difficult to deliver)
What is placenta increta ?
The placenta goes through the uterine wall
What is placenta percreta ?
Placenta goes through the uterine wall and attaches to other organs
What is a risk factor for placenta accreta ?
Previous C section
What is a complication of placenta accreta ?
PPH/ MOH
Define post partum haemorrhage (PPH) ?
> 500ml blood loss in the first 24 hours of pregnancy
What are the 4Ts of causes of PPH ?
Tone - uterine atony
Tissue- placenta accreta
Trauma- instrumental delivery
Thrombin- DIC
How does amniotic fluid embolism present ?
Sudden onset shivers, vomiting, shock and DIC
Which modality is used to diagnose haemoglobin variants ?
HPLC (high power liquid chromatography)
Elevated HbA2 >3.5% suggests which thalassaemia ?
Beta thalassaemia
How are pregnant women with sickle cell disease managed ?
Top up or exchange red cell transfusions
prophylactic transfusions
Alloimmunisation (make sure the blood is matched)
3 blood changes in pregnancy
mild anaemia - RBC mass rises, plasma volume rises, net dilution
macrocytosis
neutrophilia
thrombocytopaenia
when should a pregnant lady take folate
from before conception to > 12 weeks gestation
what platelet counts are sufficient for delivery/pidural
delivery > 50x109/L
epidural >70x109/L
treatment for ITP
IVIG
steroids
anti-D where RhD +ve
what happens in MAHA in pregnancy
deposition of platelet-rich thrombin in small BV
- shearing of RBC - haemolytic anaemia
thrombocytopenia
organ damage (kidney, CNS, placenta)
treatment for TTP
delivery does not affect the course of TTP or HUS
plasma exchange
when do most PE deaths occur in pregnancy
40-46 weeks
what investigations are safe in pregnancy for thrombosis
dopplet and VQ scans
what factors increase the risk of thrombosis in pregnancy
all - changes in blood coagulation, reduced venous return, vessel wall
variable - hypremesis/dehydration, bed rest, obesity, pre-eclampsia. operative delivery, previous thrombosis/thrombophilia, age over 35, parity, other medical problems, IVF (ovarian hyperstimulation)
prevention of thromboembolic disease in pregnancy
prophylactic heparin + TEDs
mobilise
hydration
high risk - LMWH
treatment for thromboembolic disease in pregnancy
LMWH
do not use warfarin as teratogenic
stop anticoagulation before delivery
when can an epidural be given post heparin
24 hrs after treatment dose
12 hrs after prophylactic dose
effects of thrombophilia on the pregnancy
associated with impaired placental circulation IUGR recurrent miscarriage late foetal loss abrupto placenta severe pre-eclampsia toxaemia
define placenta accreta, increta, percreta
accreta - goes trhough endometrial lining
increta - through uterine wall
percreta - through uterine wall and sticks to other organs
three things we screen for in terms of haemoglobinopathies
alpha-0-thalassaemia - death in utero
beta- 0 -thalassaemia - transfusion dependent
HbSS - 43 yr LE
counselling about haemoglobinopathies
all important ones are recessive test partner oprions: proceed prenatal diagnosis - CVS sampling, amniocentesis, Us for hydrops
complications of SCD in pregnancy
foetal GR miscarriage preterm labour pre-eclampsia venous thrombosis
management of SCD in pregnancy
RBC transfusion
prophylactic transfusion
alloimmunisation
iron deficiency vs thalassaemia trait
iron def: Hb normal/low MCH low MCHC low RDW high RC low/normal Hb electrophoresis normal
thalassameia trait: Hb normal MCH low MCHC preserved RDW normal RBC high Hb electrophoresis Hb A1c high in B that, normal in a thal trait
