Obstetric Haematology Flashcards by Georgia Leggett

What is the normal full blood count in pregnancy?

Mild anaemia: Red cell mass rises (120 -130%), plasma volume rises (150%)- net dilution

Macrocytosis: Phsyiological (+/- folate or B12 deficiency)

Neutrophilia

Thrombocytopenia: Increased turnover + platelet size

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What is the blood iron requirement of pregnancy?

Fetus: 300mg

Maternal increased red cell mass: 500mg

RDA 30mg

Increase in daily iron absorption: from 1-2mg to 6mg

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What is the folate requirement of pregnancy?

Increases for growth + cell division

~ additional 200mcg/day

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What may iron deficiency in pregnancy cause?

IUGR

Prematurity

Postpartum haemorrhage

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What is the importance of folic acid in pregnancy? What is the normal supplementation of folic acid in pregnancy?

Reduces risk of neural tube defects

Supplement before conception + for ≥ 12w gestation

Dose 400μg/day

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What is the definition of anaemia in each trimester and postpartum?

1: Hb < 110 g/l

2 + 3: Hb <105 g/l

Postpartum: <100g/l

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What is defined as major haemorrhage during labour?

Blood loss 1L

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What happens to platelets during pregnancy? What must be considered?

Platelet count falls due to increased turnover

Automated counter may not recognise giant platelets

Be aware of clumping- use film

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What are 5 causes of thrombocytopaenia in pregnancy?

Physiological: ‘Gestational’/ incidental thrombocytopenia

Pre-eclampsia

Immune thrombocytopenia (ITP)

Microangiopathic syndromes

Normal causes: BM failure, leukaemia, hypersplenism, DIC

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What is the likely cause of thrombocytopenia at each of the following platelet counts:

<150

<100

<70

<150: majority gestational, little preeclampsia, few ITP

<100: ½ gestational, ¼ ITP, ¼ preeclampsia

<70: ¼ gestational, majority ITP + Pre-eclampsia

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What is gestational thrombocytopaenia?

Physiological decrease in platelet count ~ 10%

>50x10^9/l sufficient for delivery (>70 for epidural)

MOA: Dilution + increased consumption

Baby not affected

Platelet count rises 2–5d post delivery

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What is the association between pre-eclampsia and thrombocytopenia?

50% with pre-eclampsia get thrombocytopenia

Proportionate to severity

MOA: Increased activation + consumption

A/w coagulation activation: incipient DIC

Usually remits following delivery

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Why is a greater platelet count required for epidural?

Small risk of spinal haematoma when sticking needles around spine

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What is the epidemiology of ITP?

Accounts for. 5% of thrombocytopenia in pregnancy

TP may precede pregnancy

Early onset

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What are treatment options for bleeding or delivery in ITP?

IV immunoglobulin

Steroids etc.

Vontouse delivery/ certain forceps avoided

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How are babies affected with maternal ITP?

Unpredictable effects (causes platelets <20 in 5%)

Check cord blood + then daily

May fall for 5d after delivery

Bleeding in 25% of severely affected (IVIG if low)

Usually normal delivery

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What occurs in MAHA in pregnancy?

Deposition of platelets in small blood vessels- thrombocytopenia

Fragmentation + destruction of RBCs

Stress on BM to produce more RBCs- nucleated RBC on film

Can lead to organ damage

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In which MAHA syndromes does delivery not alter the course?

TTP

HUS

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Coagulation changes in pregnancy…

A. Increase the likelihood of bleeding

B. Result in hyperfibrinolytic state

C. Are mediated by BHCG hormone

D. Result in a leading cause of maternal mortality

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Venous Thromboembolism during pregnancy…

A. Has a higher incidence period during the postnatal period

B. Is more common in women with high body mass index

C. Is more likely to occur following vaginal delivery than elective C section

D. Usually affects the right leg

B. Is more common in women with high body mass index

85% of clots in pregnant women in left leg

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What is the direct leading cause of maternal death in the UK?

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Which coagulation factors increase in pregnancy creating a hypercoaguable state?

Factor VIII + vWF x 3-5

Fibrinogen x 2

Factor VII x 0.5

Factor X

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Which coagulation factors change in pregnancy creating a hypofibrinolytic state?

Protein S falls to ½

PAI-1 increases 5-fold

PA-2 produced by placenta

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What do the coagulation changes in pregnancy result in?

Study These Flashcards

Hypercoaguable hypofibrinolytic state

Rapid control of bleeding from placental site (700ml/min) at time of delivery

Why can D-dimers not be used in pregnancy?

D dimers rise in pregnancy due to inflammation Pregnancy: hypercoaguable + HYPOfibrinolytic D dimers in non-pregnant are used as markers of fibrinolysis

Summarise the net effect of coagulation changes in pregnancy

Procoagulant state: Increased thrombin generation Increased fibrin cleavage Reduced fibrinolysis Increased rate of thrombosis

Which tests are used to identify VTE in pregnancy?

VQ perfusion or Doppler | (NOT D-Dimer)

What are factors which increase risk of VTE in all pregnant women? (Virchows triad)

Blood changes: hypercoagulable Developing gravid uterus presses down, reduced venous return- venous stasis Changes in vessel wall related to hormones

Why does 85% od DVT occur in the left leg in pregnancy compared to 55% in the left leg in the non pregnant state?

Anatomy: compression of left common iliac vein by right common iliac artery is accentuated by enlarging uterus More pressure on left side

When is risk of VTE highest in pregnancy?

Postpartum Up till 6w after birth

What has a ‘dose dependent’ effect on risk of PE death in pregnancy?

BMI

What 11 variable factors which increase risk of VTE in pregnant women?

**Hyperemesis/ dehydration** **Bed rest** **Obesity:** BMI\>29 3x risk of PE **Pre-eclampsia** **Operative delivery** **Previous thrombosis/ thrombophilia** **Age** **Parity (\>4)** **Multiple pregnancy** **Other medical problems:** HbSS, nephrotic syndrome **IVF:** ovarian hyperstimulation

Which women are identified to seek advice before becoming pregnant to reduce risk of VTE?

Overweight FH VTE PMH VTE

Give 4 symptoms of VTE in early pregnancy

Chest pain SOB Tachycardia Leg pain

What preventative measures are recommended for women with risk factors for VTE during pregnancy?

Prophylactic LMWH: either throughout or in peri-post-partum TED stockings Early mobilisation Maintain hydration

What is the treatment for VTE in pregnancy?

LMWH as for non-pregnant; does not cross placenta. RCOG recommend OD/ BD Do not convert to warfarin (crosses placenta) After 1st trimester monitor anti-Xa: 4 hour post 0.5-1.0u/ml

How long before an epidural should LMWH be stopped?

Wait 24h after tx dose 12h after prophylactic dose

Give 7 signs of chondrodysplasia punctata

Abnormal cartilage + bone formation Early fusion of epiphyses Nasal hypoplasia Short stature Asplenia Deafness Seizures

Why should warfarin not be given?

Warfarin is teratogenic in the 1st trimester Can cause Chondrodysplasia Punctata

What is antiphospholipid syndrome?

Recurrent miscarriage + persistent Lupus anticoagulant (LA) +/- antiphospholipid antibodies

What are the three potential presentations of antiphospholipid syndrome?

**Adverse pregnancy outcome:** \>,3 consecutive miscarriages before 10w gestation. \>,1 morphologically normal fetal losses after 10w gestation. \>,1 preterm births before 34w gestation owing to placental disease.

What is the potential treatment of antiphospholipid syndrome?

Aspirin + heparin | (Better than aspirin alone)

What are the 4 Ts of postpartum haemorrhage?

Tone: **Uterine atony** **Trauma:** Laceration/ Uterine rupture Tissue: Retained placenta/ site of placenta Thrombin: Coagulopathy

What amount of blood loss defines post party haemorrhage?

\>500ml

All haematological factors are minor variables for post-partum haemorrhage except:

Dilutional coagulopathy after resuscitation DIC caused by infection, placental abruption, amniotic fluid embolism etc.

What is the relationship between Disseminated Intravascular Coagulation (DIC) and pregnancy?

Coagulation changes in pregnancy predispose to DIC.

What is decomposition for DIC in pregnancy precipitated by?

Amniotic fluid embolism Abruptio placentae Retained dead fetus Preeclampsia (severe) Sepsis

List 3 signs/ symptoms of amniotic fluid embolism

Sudden onset shivers Vomiting Shock

Give 4 facts about amniotic fluid embolism

86% mortality Presumed due to Tissue Factor in amniotic fluid entering maternal bloodstream Majority \>25y Usually 3rd trimester: drugs used to induce labour e.g. Misoprolol increase risk

The aims of haemoglobinopathy screening are to avoid birth of children with…

Alpha thalassaemia: death in uteru, hydros fetalis Beta thalassaemia: Transfusion dependent HbSS (sickle cell disease): Life expectancy 43y Compound HbS syndromes: symptomatic, stroke Compound thalassaemias: transfusion dependent, iron overload

What elements are used for haemoglobinopathy detection?

Universal screening in areas with high background prevalence Family origin questionnaire in less prevalent areas FBC: Red cell indicies HPLC Molecular analysis Aim to complete by 12/40w

What should be considered in haemaglobinopathy counselling?

Important disorders are all recessive Therefore if mother is heterozygous, partner should be tested

Describe the following parameters in iron deficiency: Hb MCH MCHC RDW RBC

Hb: Normal/ Low MCH: Low (in proportion to Hb) MCHC: Low RDW: Increased RBC: Low/ normal Hb electrophoresis: Normal

Describe the following parameters in thealassaemia trait: Hb MCH MCHC RDW RBC Hb electrophoresis

Hb: Normal (rarely low) MCH: Lower for same Hb MCHC: Relatively preserved RDW: Normal RBC: Increased Hb electrophoresis: HbA2 in b thal trait, Normal in alpha thal trait

What key difference in parameters distinguish thalassaemia trait from iron deficiency?

RBC cannot be increased in iron deficiency but is ALWAYS increased in Thal trait

Which of the following statements is correct? A. In gestational thrombocytopenia the baby's platelet count is usually affected B. Thrombocytopenia is rarely found in association with pre-eclampsia C. Thrombotic Thrombocytopenic purpura remits spontaneously following delivery D. The platelet count may fall following delivery in baby's born to mothers with ITP

D. The platelet count may fall following delivery in baby's born to mothers with ITP

A reduction in pregnancy-associated thrombosis mortality rate can be attributed to: A. Lower obesity rates B. Improved targeted thromboprophylaxis C. Rising maternal age D. Increase in prevalence of gestational thrombocytopenia

B. Improved targeted thromboprophylaxis

Which of the following statements is correct? A. ~1L blood loss can be considered normal following vaginal delivery B. Uterine atony is a common cause of post partum haemorrhage C. Post partum haemorrhage is often caused by the changes in coagulation factors in pregnancy

B. Uterine atony is a common cause of post partum haemorrhage

Obstetric Haematology Flashcards

(58 cards)