What happens to cardiac output during pregnancy
Increases by 30-50% between 6-28 weeks gestation
Describe what RBC, WBC and platelets look like on a bloodfilm
RBC - medium round but hollow circles
WBC -Vary but tend to be purple and bigger
Platelets - Small dark dots
What is polycythaemia?
High Hb
How does RBC mass rise in pregnancy in a normal woman and a woman on iron supplementation?
Normal: - 17% (240ml)
Iron - 29% (400ml)
Why is there a relative decrease in RBC mass during pregnancy?
Big increase in plasma volume in first trimester
What happens to RBC mass post-partum?
Falls at delivery due to bleeding
Returns to normal by 3 weeks.
What happens to plasma volume throughout pregnancy?
Increases right from conception - by about 50% (2600ml)
Plateaus around last 8 weeks
What does Hb normally stay above in pregnancy?
11.5 g/gL (115g/l)
Why is their a physiological anaemia of pregnancy?
Although RBC mass increases, plasma volume increases more, resulting in a relative anaemia. Low Hb, haemocrit (Hct), RBC count but no effect on MCV.
Levels return to normal by labour
When does Hb fall to its lowest in pregnancy?
32-34 weeks?
What happens to MCV during pregnancy?
Doesn’t change (76-96 fL)
What is Hemochromatosis?
Iron overload of any cause. Stores excess in major organs (not just liver)
What is excess iron stored as?
Feerritin in liver
Haemosiderin in bone marrow
What is the iron requirements of a pregnant female?
4-7mg/day
What is norma serum ferritin levels?
> 15mcg/l
What blood results indicate iron deficiency in pregnancy?
Hb <105g/l (consider if <115g/l)
MCV - goes up in pregnancy (fresh RBC are bigger) - can’t exclude iron deficiency in normal MCV. (can increase to 105fl)
Check serum ferritin (<15mcg/l) = anaemia
What are the advantages and disadvantages to IV iron?
No advantages
Anaphylaxis in IV iron
What are the side effects of oral iron?
Nausea, Abdo pain, Constipation, Diarrhoea, Black stools
What does a deficiency in cobalamin and folate cause?
Impairs DNA production
Reduces RBC production
If suspecting Folic acid or B12 deficiency, what might you measure?
Homocysteine - can’t recycle it if deficient (will increase)
Do not measure B12 levels in pregnancy unless …
MCV high
Serum B12 falls in pregnancy. May be below 100pmol/l (normally >150)
What is the normal requirement and pregnancy requirement of folic acid?
Normal - 100ug/day
Pregnancy - 300-400ug/day
Why is folic acid deficiency uncommon?
Stores last for 3 months
What is thrombocytosis?
High platelets (>500 x 10^9/l)
What is thrombocytopenia?
Low platelets (<150x10^9/l)
What can cause thrombocytopenia?
Reduced production of platelets (by bone marrow)
Increased consumption
What is aplastic anaemia?
Bone marrow failure - reduced production
What would happen to RBC, WBC and Platelets in blood marrow infiltration/failure/suppression?
Anaemia
Leucopenia
Thrombocytopenia
What cell produces platelets in bone marrow?
Megakaryocytes
Give some in and out of pregnancy causes of increased consumption of platelets
In or out:
- Auto-immune
- Sepsis
- Massive haemorrhage
- Cardiac bypass
- Hyperslenism (more space for platelets)
Pregnancy:
- HELLP
- Pre-Eclampsia
- Gestational thrombocytopenia
What happens to RBC, WBC and platelets in increased consumption of platelets (thrombocytopenia)?
RBC = Normal WBC= NORMAL Platelets = REDUCED
What is normal platelet count in pregnancy?
150-450 x 10^9 / l
Thrombocytopenia
<100 x 10^9 / l
Why are pregnant women more likely to clot in pregnancy?
Virchow’s triad
increased pro-coagulant, Endothelial damage, venous stasis
What vein is likely to compressed in pregnancy and why?
Left common iliac vein
Uterus growns - compresses on right iliac artery which in turn compresses the vein behind it
What pregnancy risk factors increase the risk of Venous thromboembolism?
Hyperemesis Pre-eclampsia Ovarian hyperstimulation syndrome Transfusion Caesarian Instrumental delivery Obesity
What is HELLP syndrome?
Rare liver and blood clotting disorder that can effect pregnant women
H - Haemolysis
EL - elevated liver enzymes
LP - Low platelet count
Which is the universal RBC donor?
O group
What is the platelet and plasma universal donor?
AB group
Does blood group AB have A or B antigens?
NO - can receive any blood group
If a pregnant woman is rhesus positive after her first born. What is the risk with the second born?
She will develop anti-D, it can cross the placenta and destroy the baby is also rhesus positive
What do you do to prevent sensitisation of RhD-negative women during pregnancy?
Give them anti-D after each potentially sensitising even during the pregnancy.
Within 72h or childbirth (if child is RhD+)
How are RBC stored?
4oC - half shelf life of 35 days
How is FFP stored?
-30oC, shelf life of 24 months
What is Cryoprecipitate?
Rich source of fibrinogen
Should you give FFP to a warfarin patient?
NO, give Beriplex (prothrombin concentrate) to reverse its effects in life threatening situations
Give 2 conditions when you would give FFP
DIC and TTP - clotting factors used up so need to be replaced
How are platelets stored?
Room temperature, 5 day shelf life