Thrombocytopenia in Pregnancy (ASH 2013 guideline)

Definition: Plt Count <100 x109/L (International Working Group)



2nd most common haematologic abnormality in pregnancy, after anaemia

6-11% of women have plt count <150 in third trimester


Haematologist’s role:

-       Determine the cause, advise on management, estimate risk to mother and fetus


Common Scenarios

1.     Pre-existing thrombocytopenia

2.     Decreasing platelet count or newly discovered thrombocytopenia in pregnancy, which may or may not be related to the pregnancy

3.     Acute onset thrombocytopenia in the setting of severe pre-eclampsia, HELLP or AFLP


Causes (% relative incidence)


Isolated thrombocytopenia

-       Gestational Thrombocytopenia                                           70-80%

-       Primary ITP                                                                           1-4%

-       Secondary ITP -Hep C, HIV, H. pylori                                  1%

-       Drug-induced

-       Type IIb VWD

-       Congenital thrombocytopenias


Thrombocytopenia associated with systemic disorders

-       Severe pre-eclampsia                                                           15-20%

-       HELLP                                                                                     <1%

-       AFLP                                                                                       <1%

-       TTP / aHUS

-       SLE

-       Antiphospholipid Syndrome

-       Viral infections

-       Nutritional deficiency

-       Splenic sequestration (liver disease, portal vein thrombosis)

-       Thyroid disorders


Basic Investigations


FBC, reticulocyte count, blood film


Viral Screening


Also consider if indicated:

-       ANA, TFT, H. pylori, PT/APTT/FGN, DAT, Immunoglobulins


Gestational Thrombocytopenia


Platelet Count >70 + No neonatal thrombocytopenia + spontaneous maternal resolution


5-9% of pregnancies, 70-80% of all thrombocytopenias in pregnancy



-       Occurs in mid-second to third trimester

-       Resolves within 6 weeks post-partum, may recur with subsequent pregnancies

-       Not associated with neonatal thrombocytopenia



-       Unknown, ?dilution + accelerated clearance


Management of Mother

-       Exclude other causes

-       If plt count <70, question diagnosis

-       Repeat FBC 6 weeks post-partum


Management of baby

-       If suspicious, Cord FBC and repeat at day 4 to exclude ITP


Immune Thrombocytopenia (ITP)


Platelet Count <100 +/- symptoms



-       Onset at any time



-       Initial response: 2-14 days

-       Peak response: 4-28 days

-       Prednisolone preferred to dexamethasone (which crosses placenta)

-       Dose

o   ASH 2011 recommend 1mg/kg prednisolone

o   But other experts recommend 0.25-0.5mg/kg and titrate to effect



-       Initial response: 1-3 days

-       Peak response: 2-7 days

-       Dose: 1g/kg


Other treatments

-       Splenectomy

-       Relatively contra-indicated: Anti-D Ig, Azathioprine

-       Not recommended, but case resports: Cyclosporin, Dapsone, TPO agonists, Rituximab

-       Contraindicated: MMF, Cyclophosphamide, Vinka alkaloids, Danazol


ITP Pregnancy Management Plan



Plt count >30 and no bleeding symptoms

- No treatment until 36 weeks, or sooner if early delivery

Plt count <30 or clinically significant bleeding

- First line: Prednisolone 0.25 - 1mg/kg or IVIg 1g/kg

- Second line: Combination treatment or splenectomy


Mode of delivery determined by obstetric indications

- Very low risk of ICH (<1.5%) or mortality (<1%)


- Platelet count >50 prior to labour as C-section is a risk with any pregnancy

- Platelet count >80 required for neuroaxial anaesthesia


Plt count <80 but not required treatment during pregnancy

- Start 10-20mg prednisolone 10 days prior to expected delivery and titrate


Plt count <50 and delivery is imminent

- Platelet transfusion combined with IVIg



No scalp monitoring / percutaneous umbilical cord blood sampling (PUBS)

Cord blood FBC & hold Vit K until result known

If cord FBC normal, Repeat FBC at day 4

Expect spontaneous rise above nadir by day 7

Consider cranial USS if plt <50. Consider single dose IVIg if plt <20 or bleeding



Increased risk of VTE, ensure prophylaxis arranged


Severe Pre-Eclampsia / HELLP / AFLP


Severe Pre-eclampsia

-       Pre-eclampsia affects 5-8% of pregnancies

o   Sys >140 or Dys >90 + >0.3g/24 hour proteinuria after 20 wks gestation

-       Severe pre-clampsia

o   Several different criteria, one of which is plt count <100

o   Thrombocytopenia may precede the other manifestations

o   Can present postpartum


Haemolysis, Elevated Liver enzymes and Low Platelets (HELLP)

-       Variant of pre-eclampsia, in some cases HTN and Proteinuria not present

-       70% in late second to third trimester, 30% postpartum

-       MAHA + Raised AST + Thrombocytopenia


Acute Fatty Liver of Pregnancy (AFLP)

-       Plt count >50

-       Rare but serious condition of third trimester

-       Elevated liver enzymes, conjugated bilirubinaemia, coagulopathy

-       Overlaps with HELLP, differentiation not clearly defined but MAHA unusual


Obstetric Management

-       IV magnesium to prevent seizures, Anti-hypertensives for BP

-       >34 weeks

o   Delivery

-       <34 weeks and maternal/fetal status acceptable

o   Steroids for lung maturation and deliver after 48 hours

-       <34 weeks and maternal/fetal status unacceptable

o   Delivery


Haematology Management

-       Supportive care with platelet transfusion

-       Steroids increase plt count but do not improve outcomes

-       Plasma exchange if plt, haemolysis or renal failure no better 48-72 hours after delivery




Difficult to differentiate severe pre-eclampsia, HELLP, AFLP, TTP and aHUS

-       TTP: ADAMTS13 <5%

When indicated, therapeutic plasma exchange is beneficial in all of these conditions and so diagnostic certainty not required in emergency setting.

See MAHA & TTP section in Coagultation Tab