W27 - Obstetric haem Flashcards
During normal pregnancy…
- Less iron is required
- There is an increase in haemoglobin concentration
- The platelet count falls
- The neutrophil coutn falls
- The platelet count falls
FBC in pregnancy - what happens to red cell mass, plasma volume, red cell size, neutrophil count, platelet count
FBC in pregnancy - what happens to red cell mass, plasma volume, red cell size, neutrophil count, platelet count
- Red cell mass rises (120-130%)
- Plasma volume rises (150%)
= net dilution so mild anaemia
- Macrocytosis (normal, or may be folate/b12 def)
- Neutrophilia
- Thrombocytopaenia (reduced count, size increased)
Iron requirments in pregnancy
- foetus, maternal, total RDA
300 mg for foetus
500 mg for maternal increased red cell mass
RDA 30 mg
Daily iron absorption goes from ______ to ____ in pregnancy
Daily iron absorption goes from 1-2mg to 6mg in pregnancy
folate requirements in pregnancy
needed for additional growth and cell division
–Approx additional 200mcg/day required
Folic acid dose & duration for pregnancy
& why?
–Dose 400μg / day supplement before conception and for ≥ 12 weeks gestation
(5mg dose for those who are high risk)
to avoid neural tube defects
Anaemia in pregnancy - definition by trimester
–Hb < 110 g/l 1st trimester
–Hb < 105 g/l 2nd and 3rd trimester
–Hb < 100 g/l postpartum
Treatment of (mild) iron deficiency anaemia in pregnancy
- Trial of oral iron, continue at least 3 months beyond correction of Hb to replenish iron stores
- If not corrected, consider haemoglobinopathy screens
4 causes of thrombocytopaenia in pregnancy
- Gestational/incidental thrombocytopaenia
- Pre-eclampsia
- ITP
- Microangiopathic syndromes
other causes: BM failure, leukaemias, hypersplenism, DIC, etc.
nPhysiological decrease in platelet count during pregnancy is roughly… %
~ 10%
Platelet count sufficient for delivery is….
Platelet count sufficient for epidural is….
>50 x109/L sufficient for delivery
>70 x109/L sufficient for epidural
Mechanism of gestational thrombocytopaenia
Mechanism poorly understood, likely:
Dilution + increased platelet consumption
___% of women with pre-eclampsia develop thrombocytopaenia, and this is proportionate to _____
50% of women with pre-eclampsia develop thrombocytopaenia, and this is proportionate to severity
Immune thrombocytopaenia (ITP) in pregnancy:
- % of thrombocytopaenia in pregnancy
- treatment?
- effect on baby?
Immune thrombocytopaenia (ITP) in pregnancy:
- % of thrombocytopaenia in pregnancy = 5%
- treatment = IVIG + steroids
- effect on baby = unpredictable, but may affect baby as IgG abs can cross placenta. Tend to avoid ventous delibery and invasive foetal monitoring methods
Coagulation changes in pregnancy…
A) increse the likelihood of bleeding
B) Result in a hyperfibrinolytic state
C) Are mediated by BHCG hormone
D) Result in a leading cause of maternal mortality
D) Result in a leading cause of maternal mortality
Venous thromboembolism during pregnancy….
A) Has a higher incidence than during postnatal period
B) Is more common in women with high BMI
C) Is more likly to occur following vaginal delivery than elective C-section
D) Usually affects the right leg
B) Is more common in women with high BMI
VTE has more or less remained a leading cause of mortality in pregnancy, accounting for about 30% of all deaths - T or F?
True
Summarise coagulation changes (6) in pregnancy
- Factor VIII and vWF => x 3-5 fold
- Fibrinogen => x 2 fold
- Factor VII => x 0.5 fold
= hypercoagulable
- Protein S => falls to 1/2 basal
- PAI-1 => x5 fold
- PAI-2 priduced by placenta
= hypofibrinolytic
What is the net effect of coagulation changes in pregnancy? and why is it like this?
A procoagulant state (increased risk of thrombosis)
This is evolved so that the body can reduce the risk of bleeding at the time of placental separation and uterine contraction.
At what time is VTE most common in pregnancy times?
Postpartum (about 1-6weeks post delivery)
Most significant RF for VTE identified in maternal deaths due to PE?
High BMI
Incidence of thrombosis in pregnancy?
1 per 1000 <35 years
2 per 1000 >35 years
DVT in pregnancy - which side is more common?
Left DVT (85%) - much higher compression on left side
Age and VTE correlation in pregnancy?
Increase together
