HOW Collaborative position paper on thrombocytopenia in pregnancy

HOW Collaborative position paper on the management of thrombocytopenia in pregnancy

Position paper published in ANZJOG Jan 2021.

https://doi.org/10.1111/ajo.13303

Causes

• Gestational (70-80%)
• Primary immune thrombocytopenia (ITP) (1-2%)
• Secondary ITP, eg due to human immunodeficiency virus (HIV), hepatitis C, systemic lupus erythematosus
• Congenital
• Drug-induced
• Type IIb von Willebrand’s disease (VWD)
• Antiphospholipid syndrome
• Splenic sequestration, eg liver disease, portal hypertension
• Bone marrow disorders
• Nutritional deficiency, eg vitamin B12/folate
• Pregnancy-associated microangiopathy
  • Preeclampsia/haemolysis, elevated liver enzymes, low platelets syndrome (HELLP)
  • Thrombotic thrombocytopenic purpura (TTP)
  • Haemolytic uraemic syndrome (HUS)
• Acute fatty liver of pregnancy
• Sepsis
• DIC
• Spurious/Pseudothrombocytopenia (clumping)

Initial investigations (if platelet count <70)

• Full blood count and reticulocyte count
• Peripheral blood film
• Optical platelet count (if available)
• Coagulation screen
• Renal and liver function tests
• Thyroid function tests
• Direct Coombs test
• Antiphospholipid antibodies: lupus anticoagulant, anticardiolipin antibodies, beta 2 glycoprotein 1 antibodies
• Antinuclear antibody (ANA)
• Hepatitis B/C and human immunodeficiency virus (HIV) serology
• Helicobacter pylori
• Vitamin B12/folate
• Immunoglobulins

Management

• Monthly platelet count in pregnancy, fortnightly if <100 from 36 weeks
• Withhold aspirin if platelets <50
• IM injections contraindicated if platelets <50 (Give IV Rhophylac instead of Anti-D)
• Treatment indications: Platelets <20, Bleeding attributed to low platelets, Platelets <50 and pre-procedure (surgery/CVS)/birth imminent/planning neuraxial anaesthesia with platelets <70

Regimens

• IVIG and prednisone are equally effective first-line treatments
  • Start with 20-25 mg prednisone PO daily
  • 40-50 mg prednisone PO daily for platelets <20 or acute bleeding
  • Response takes 4-28 days
  • Prednisone side effects: GDM exacerbation, hypertension, poor sleep, gastritis, mood disturbance
• IVIG indicated for life-threatening haemorrhage around delivery
• 1-2 g/kg as single or divided dose
• Response 2-7 days
• Adverse effects: transfusion reaction, headache, aseptic meningitis, thrombosis

Labour and birth

• Platelets <100: MDT approach, Birth in hospital, Induce at term
• Target platelets >50 for: Vaginal birth, Instrumental, Caesarean, Clexane use
• Target platelets >70 for allow regional anaesthesia (spinal is less traumatic than epidural)
• Stress steroids in labour: IV hydrocortisone 50 mg Q6H from established labour to 6 hours after birth. For caesarean, give 100 mg IV hydrocortisone at time of anaesthesia, then 6 hours post-birth
• Mode of birth: Lack of data to inform instrumental risks. ITP is associated with a small increase in neonatal thrombocytopaenia.

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