Pregnancy Flashcards
What are increased haematological maternal demands in pregnancy?
- increased iron requirement (plus 200mg for foetus + 500mg for increased red cell mass)
- increased folate requirement
What is the recommended dose for folic acid supplementation in pregnancy
400 microgram/day
Why is the anaemia threshold in pregnancy?
Lower than ususal (due to increased
1. Hb <110 in 1st trimester
2. Hb <105 in 2nd +3rd
3. Hb <100 postpartum
What is the physiological change in platelet count during pregnancy?
Thrombocytopenia (~ 10% decrease mainly 3rd trimester)
Due to Increased turnover and clearence of platelets (dilution + increased consuption)
Normalises 2-5 days post-delivery
What are pathological causes of thrombocytopenia in pregnancy?
Especailly in low platelet counts (e.g. <100, <70)
- pre-eclampsia
- ITP (immunosuppression makes worth)
- Microangiopathic syndromes
- Other non-pregnancy specific reasons, e.g. leukaemia, BM failure
What are safe levels for pt count for delivery?
- <50 sufficient for delivery
- > 70 for epidural (spinal haematoma)
What are the characteristics of MAHA on blood film?
Microangiopathic haemolytic anaemia
- schistocytes (due to platelet rich clots in small vessels)
What are the coagulation changes in pregnancy?
Generally increase in coagulation (to limit blood loss during delivery)
Increase - Hypercoagulable
1. Factor VIII and vWF (3-5x)
2. Fibrinogen (2x)
3. Factor VII
Decrease - Hypofibrinolytic
Protein S
(increased D-dimern normal in pregnancy)
Placental
PAI 1 and PAI 2
Why is there are higher incidence of VTE in pregnancy?
When is the highest risk?
Highest risk in 6 weeks post-partum period
All parts of Virchows triad effected
1. Hypercoaguable state
2. Change in Flow (reduced venous return, 85% of DVT in left side)
3. Hormonal changes in vascular wall
What is the leading cause of maternal deaths in the UK?
PEs
What is the highest risk factor for maternal mortality due to PE?
High BMI
(+ 2x likely in <35)
How can Thromboembolic diseases be prevented in pregnancy?
Depending on risk asessment for VTE
1. Prophylactic hepatin + TED stockings
2. Very high risk: dose asjusted LMWH
2. Early mobilisation
3. Hydration
What is the management for VTE in pregnancy?
- LMWH (OD/ BD) - no placental crossing
- NOT warfarin (crosses placenta)
- After 1st trimester: monitor Xa
What are the effects of warfarin during pregnancy?
- Chondrodysplasia Punctata
Very severe, absoloute contraindication
What are the factors that will make Antiphospholipid syndrome more common?
Recurrent miscarriage
>3
What are major risk factors for fatal maternal bleeding?
Placenta praevia
Placenta accreta
Other causes of PPH usually aren’t fatal
What are th causes of postpartum haemorrhage
4Ts
1. Tone - less uterine contraction
2. Trauma
3. Tissue
4. Thrombin - usually more minor (e.g. dilutional coagulopathy after resuscitation, DIC in abruption, anmiotic fluid embolism)
What haematological screening tests are done during pregnancy?
For
1. alpha (Hb barts) thalassaemia –> death in utero+ hydops fetalis)
2. ß thalassaemia major : transfusion dependant)
3. Sickle Cell
How are haematological screening in pregnancy done?
- Family origin quessionaire
- Parental teting
- Foetal testing
- don’t have to do
5.
How can you differentiate between Iron deficiency and Thalassaemai trait on lab resultsß
What are physiological changes on an FBC in pregnancy?
RBC/ HB
- Red cell mass rises (120 -130%)
- Plasma volume rises (150%)
- –> Dilution and fall in Hb (NR 115-130)
Platelets
- thrombocytopenia with increased pt size
Mild
- Neutrophilia
- Macrocytosis
What is the clinical presentation of n amniotic fluid embolism?
1 in 20000-30000 births
* Sudden onset shivers, vomiting, shock. DIC
n 86% mortality (16 deaths in last triennium)
- almost all >25 years, usually in 3rd trimester
- Presumed due to Tissue Factor in amniotic fluid entering maternal bloodstream
What is HELLP syndrome?
What are some lab findings?
HELLP syndrome = life-threatening complication that can develop 2nd to pre-eclampsia
- Haemolysis (MAHA - reduced HB, increase LDH, increase bilirubin)
- Elevated Liver Enzymes (↑↑AST, ↑↑ALT)
- Low Platelets (but normal APTT, PT)
What are differentials for a suspected HELLP syndrome?
DIC (↑APTT, ↑PT, ↓fibrinogen),
AFLP (marked transaminitis) - acute fatty liver of pregnancy
How would haemolytic disease of the newborn present?
Haemolysis due to maternal antibodies (IgG crossing the placenta)
–> anaemia + Jaundice
How is prevention of haemolytic disease of the newborn done in rhesus negative mothers?
Generally
1. Establish rhesus status of fetus (based on bloods)
2. If Mother -ve, fetus +ve: Give Anti-D
Give Anti-D at
* 28+34 weeks
* at delivery
* any event with hight risk of fetal blood entering maternal circulation (haemorrhage, miscarriage etc. )